AMERICAN JOURNAL OF CLINICAL PATHOLOGY
Special Article
Laboratory Turnaround Time
PAUL VALENSTEIN, MD
"Well done is quickly done."—Augustus Caesar
The virtue of speed, recognized by Caesar almost two
millennia ago, infuses contemporary values. Currently,
consumers can have their photographs developed within
1 hour, meals served within 1 minute, or bank funds
transferred in less than 1 second. We view the speed with
which a service is delivered as a desirable quality in and
of itself, even when the service in question is not needed
immediately.
The importance society attaches to speedy service extends to the clinical laboratory. In some situations short
laboratory turnaround time may impact a patient's clinical course more than achieving a high level of accuracy.'"3 The physician taking care of a comatose patient
in the emergency room will make more use of a serum
glucose level of 30 mg/dL reported after 5 minutes than a
more accurate report of 36 mg/dL reported after 1 hours'
delay.
The speed with which laboratory results are reported
impacts the institution as well as the patient. When results of routine laboratory tests are delayed, physicians
show a tendency to reorder the same test.45 In a randomized trial, McDonald and colleagues6 studied the effect of
furnishing an immediate computer-generated summary
of patients' previous laboratory results on physician testordering in an emergency room. When a computer-generated summary was provided, internists ordered 16%
fewer tests in the emergency room than when they had
to wait for the medical records department to retrieve the
patient's medical chart, and total laboratory costs were
reduced by 14%. Laboratory delays also increase the
lengths of some hospitalizations. Selker and colleagues7
reported that problems obtaining laboratory test results
caused 9% of medically unnecessary hospital delays in a
tertiary care teaching hospital.
In the commercial laboratory marketplace, speed assumes special importance because laboratory customers
demand it. The manager of a typical commercial laboratory will review and post daily reports summarizing turnaround time from the previous evening. Whether or not
faster turnaround time is likely to make any medical
difference, patients and their physicians want reports as
rapidly as possible. The women who has a Papanicolaou
smear wants her report back in 3 days, although she may
be screened once every 3 years.
Thus, rapid laboratory turnaround is important from
a cultural, medical, logistical, and commercial perspective. When turnaround time does not meet customers'
expectations, they frequently let laboratory management
know about their problem. More than four fifths of hospital-based laboratories receive complaints about test
turnaround time.8 Pressure to discharge inpatients as
quickly as possible, and intense competition in the outpatient testing marketplace, are likely to heighten clinicians' demands for more rapid laboratory turnaround
time in the future.9
This paper will review major issues in the measurement of laboratory turnaround time, summarize benchmark turnaround data from inter-institutional surveys,
and highlight approaches that have been used (with varying success) to shorten laboratory turnaround.
MEASURING TEST TURNAROUND TIME
To determine whether performance is meeting clinical
expectations, whether turnaround time in an institution
is improving or deteriorating, or how performance in a
particular laboratory compares with other institutions, it
is necessary to measure turnaround time in a systematic
manner. Although this would seem to be an easy undertaking, there is no consensus within the laboratory
community about how best to go about measuring turnaround time. More than half of surveyed laboratories report that they prepare regular turnaround time reports.I0
Yet, institutions differ significantly in the way they define
turnaround time, which tests and patients are included,
and the descriptive statistics used to summarize laboratory
performance.
From the Department ofPathohgv, St. Joseph Mercy Hospital, P.O.
Box 995. Ann Arbor, MI 48106.
Intervals in the Testing Cycle
A moment's reflection reveals that the period between
the time a test is ordered and the time the result is noted
Manuscript received December 28, 1995; accepted January 4, 1996.
Address reprint requests to Dr. Valenstein: Department of Pathology,
St Joseph Mercy Hospital, P.O. Box 995, Ann Arbor, MI 48106.
676
VALENSTEIN
677
d Time
can be divided into a number of distinct intervals. 1 " 1 2
Most broadly, the testing cycle can be divided into three
phases. The "pre-analytic" interval extends from the
time a test is ordered until the time the specimen reaches
the testing facility. The "analytic" interval extends from
the time the specimen is received to the time the result is
verified in a computer or printed for distribution. The
"post-analytic" interval extends from result verification
or printing to the time a physician actually sees the result.
Each of these intervals can be further subdivided. Some
years ago, Barnett and colleagues4 identified 10 different
intervals in the testing cycle. The Quality Assurance (QProbes) Committee of the College of American Pathologists recognizes 14 different milestones in the testing cycle, which are detailed in Table 1. Turnaround time can
potentially be measured between each milestone, although the College uses only some of the intervals in its
interinstitutional turnaround time surveys.
To avoid confusion, it is helpful to specify the interval
of interest when reporting turnaround time performance. Thus, it is desirable to speak of order-to-receipt
turnaround time, or collection-to-verification turnaround time, rather than use the term "turnaround
time" without any modifiers. It hardly needs noting that
the reported performance of two laboratories is not directly comparable if they are not measuring the same interval.
Laboratory managers often equate turnaround time
with the interval between a specimen's arrival in the laboratory and the time the result is issued. 21314 This interval is most directly under control of the laboratory
manager, but represents only a part of the testing process
perceived by the laboratory's customers. Three important components of the testing cycle in outpatients that
are often overlooked are order-to-collection time, patient phlebotomy waiting time, and verification-to-report-delivery time. The three intervals most commonly
reported in inpatient and emergency department turnaround surveys are collection-to-verification, collectionto-receipt, and receipt-to-verification turnaround. Only
the last interval, receipt-to-verification, corresponds to
what is called "within laboratory" or "analytic" turnaround time—the interval with which laboratory managers have traditionally concerned themselves.
Turnaround Time as a Distribution
Figure 1 shows the receipt-to-verification turnaround
time of 11,070 stat prothrombin times performed by a
single laboratory during a calendar year. Receipt-to-verification turnaround time is quite variable. In this laboratory, some tests take less than 20 minutes to complete,
whereas others take several hours. The distribution
shown in Figure 1 departs in several respects from the
familiar Gaussian or "normal" distribution. The distribution is positively skewed, having a longer tail on the
right than the left. It is also more peaked (leptokurtotic)
than a normal distribution. Skewness and kurtosis can
be expressed quantitatively. Most turnaround time distributions that the author has examined have skewness
in the range of 2 to 8. Laboratories with turnaround time
problems generally have more skewed turnaround time
distributions. The degree of kurtosis usually ranges from
15 to 150 and is of uncertain significance.
The receipt-to-verification turnaround time distribution can be broken down into three segments, designated
in Figure 1 as A, B, and C. The first segment consists of a
short interval during which no tests are completed. This
interval represents the minimum amount of time required to complete a test. In the case of stat coagulation
tests in the laboratory that supplied data for Figure 1,
it includes the minimum time required to accession the
specimen, separate the plasma, run the specimen
through an automated analyzer, transmit the results
from the analyzer to the laboratory information system,
and verify the results in the computer. The second segment extends from the time the first test was reported to
the mean turnaround time. This segment includes most
specimens that were analyzed when all processes were
working reasonably well. The length of this segment relates most closely to the amount of specimen batching
that is taking place. When technologists wait for several
specimens to accumulate before running an assay, the
second segment is longer. The third segment in the turnaround time distribution includes all specimens that
took longer than the mean turnaround time to be processed. The length of this segment is most closely related
to the frequency of laboratory mishaps that affect turnaround time. A long third segment may indicate that too
many specimens are being temporarily misplaced, specimens are arriving in the laboratory when an analyzer is
not functioning properly, that too many tests have to be
rerun, or that the laboratory staff is frequently unable to
handle the specimen workload.
Summary Statistics
When laboratory turnaround time is measured in
practice, the distribution of turnaround times is typically
summarized with descriptive statistics. Four statistics are
commonly used: the mean, the median, the 90th percentile, and the proportion of tests that are processed within
a pre-defined limit. This last statistic is sometimes referred to as the proportion of acceptable tests (PAT).
Different descriptive statistics serve different purposes.
The mean is the best measure of turnaround time for
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AMERICAN JOURNAL OF CLINICAL PATHOLOGY
Special Article
TABLE 1. STEPS BETWEEN ORDERING AND OBTAINING TEST RESULTS
Order
The date and time a test or procedure is requested by a physician. This request is usually evidenced by a written order on an order sheet or
laboratory requisition. For verbal orders it is the date and time the verbal order was given, as recorded by the individual who took the verbal order.
An order normally occurs before a specimen is collected. However, so-called "add test" orders may be added to an already collected specimen to
request additional tests. For reflexively ordered tests, which are ordered on the basis of a rule or algorithm, the date and time of order is the time in
which all information became available to evaluate and execute the rule or algorithm used to order the procedure.
Order Entry
The date and time an order is entered into thefirstcomputer system that is used to electronically communicate the request to a testing facility or
clinical laboratory. This may involve entry of an order into a laboratory-based computer system, a hospital-based computer system, or an officebased computer system. When no computer system is used at any step in the process, the order entry time becomes synonymous with the order
time. Note that after "order entry," communication of the test request to the clinical laboratory may not involve a manual transfer step between
computer systems. Thus, if an order is entered into a "stand-alone" office-based computer system which causes a requisition to print, and
information on the requisition is later entered into a laboratory computer system by hand, the "order entry" time is the time the information was
entered into the laboratory system, not the office-based system.
Patient Presentation
The date and time in which a patient presents for specimen collection. For outpatients, this is the date and time a patient arrives at a specimen
collection facility or area of a clinic or physician's office designated for specimen procurement. For inpatients scheduled for specimen collection,
this is the time the patient becomes available for specimen collection after the scheduled collection time. For example, if the patient is scheduled
for collection at 6:00 a.m. and is not available until 6:05 a.m., patient presentation is at 6:05 a.m. For unscheduled inpatient collections, and
collections that take place in the emergency department or operating theater, thisfieldhas no value.
Registration Begins
The date and time the registration process starts. Registration consists of obtaining patient information necessary to perform the ordered test
(minimally, patient identification, age, and sex) and any additional historical information required to perform the procedure. It is most commonly
tracked for computing turnaround time in the outpatient setting, where patients must wait for registration (sometimes in a separate computer
system) before the test can be order entered.
Registration Ends
The date and time the registration process is completed.
Collection
The date and time the specimen is collected. For specimens that take more than one minute to collect, such as surgical specimens or, often, urine
specimens, this is the date and time the specimen is inserted into a transport device, labeled, and is available for transport.
Courier N Pick up
This is the date and time the Nth courier picked up the specimen. The term "courier" refers to a driver, runner, or mechanical transport system
used to move a specimen from one location to another. N is given a value of 1 for thefirstcourier system to pick up a specimen. Specimens may be
carried by a number of couriers and courier systems before they reach a testing site.
Courier N Delivery
The date and time the specimen is delivered by the Nth courier.
Receipt in Testing Laboratory
The date and time a specimen is received in the laboratory that houses the testing site. "Laboratory" refers to a building or set of interconnected
buildings that contain the testing site. Buildings that are not connected are considered separate laboratories in this definition, even if they have the
same corporate ownership or provide services under the same provider license.
Received in Testing Site
The date and time a specimen is received at the section of the laboratory in which it is to be tested. The site may be a microbiology section or
histopathology accessioning area. Alternatively, it may be a particular work station within the microbiology section or histopathology section. The
definition of a testing site will accordingly vary from institution to institution.
Intermediate Testing Milestone N
The date and time an intermediate testing milestone is completed. Different procedures may have different milestones that are normally
completed in sequence. The different milestones are designated with an integer in the "N" position. For example, for a routine surgical pathology
specimen, intermediate testing milestone 1 may be defined as entry of the specimen into an electronic or paper log book, while intermediate
testing milestone 2 may be defined as completion of the gross examination.
Verification of Result
The date and time a result passes all internal laboratory checks and is ready for communication/distribution/release to a patient's physician or
other provider. This is the point at which the result, for legal purposes, is considered to have been "released" from the laboratory. A physician or
other authorized provider inquiring on a test result would normally not be provided with the result prior to its verification, and would be allowed
to obtain the result after it had been verified.
Delivery to Provider N
The date and time that a result is delivered to a provider of class "N" in oral, written, or electronic form. "Delivery" here refers to the routing of a
result to a location at which the provider is expected to be found, unless he or she has indicated that the result should be delivered to an alternate
destination. Results delivered to an incorrect location are not considered delivered.
Seen by Provider N
For results delivered in written or electronic form, this is the time that thefirstprovider of class "N" actually saw the result.
A.J.C.P.-Junc 1996
VALENSTEIN
Turnaround Time
A B
C
Roc«ipMo-Vor1fication TAT [Hounl
FlG. 1. Within laboratory (receipt-to-verification) turnaround time of
11,070 stat partial thromboplastin times at a single institution. Turnaround time distribution is divided into three segments.
laboratories with poor performance that are following
turnaround for signs of improvement.5 However, when
the sample size is small (fewer than 25 tests), the median
is preferred to the mean.
The mean and median are not good statistics for laboratories with normally good performance that are interested in improving further, because the mean and median are not significantly influenced by outliers—tests
that take longer than normal to process because of a
breakdown in standard procedures. Mean laboratory
turnaround time may be within acceptable limits,
whereas 25% or more specimens have unacceptable delays. For laboratories with normally good performance,
the turnaround time of the 90th percentile test or the
PAT are the best measures for summarizing the frequency of mishaps and tracking further improvement.
Most laboratories should track turnaround time using
at least two different measures. The mean or median
should be used to track "average" laboratory performance, whereas the 90th percentile or PAT should be
used to identify the frequency of outliers. The author recommends that laboratory performance be plotted regularly, on a daily, weekly, or monthly cycle. The two summary statistic should be charted separately.
Turnaround Time Statistics and Quality Control
Turnaround time summary statistics can be plotted
and analyzed like other quality control data. When the
mean is used to summarize turnaround time, daily or
679
weekly turnaround time performance can be plotted using a Shewart quality control chart." The same Shewart
rules used by laboratories to identify when a chemistry
or hematology analyzer is "out of control" can be applied to a series of turnaround time means. The quality
assurance division of the McDonald's restaurant corporation uses a variant of this approach when monitoring
the amount of time customers spend waiting in line or at
a counter. Field consultants periodically measure customer waiting time at individual restaurants, and response time is said to be in control if the mean wait plus
3 standard deviations (SD) decreases below a ceiling that
has been established (R. Julseth, McDonald's corporation, personal communication).
When the PAT is being used to follow the frequency
of outliers, turnaround time is expressed as a proportion
or percentage of acceptable tests.16 In this case a type of
control chart called a P chart, which is used in industry
to track the fraction of acceptable product, can be used
to determine when performance is out of control.17 The
Dominoes Pizza Corporation uses this approach to monitor delivery of their product. Turnaround performance
is expressed as the proportion of pizzas delivered within
the promised turnaround time, and is followed using a P
chart.
Measuring Turnaround Time of Open-Ended Tests
Certain types of tests, by their nature, leave the laboratory with a good deal of latitude in deciding what to do
with a specimen. For example, a pathologist studying a
liver biopsy might report some cases after examining
only hematoxylin-and-eosin-stained sections, while delaying other cases for additional stains. Many microbiology tests can also be considered open-ended tests. Depending on what grows on a plate after 24 hours, a urine
culture might be signed out as negative or might demand
identification and susceptibility testing that require an
additional day or longer. Preliminary reports or addendum reports may be issued for anatomic pathology and
microbiology tests as new information becomes available.
An analysis of turnaround time for open-ended tests is
necessarily more complicated than for tests where every
specimen is treated identically, and an entirely satisfactory approach has not been developed. When the proportion of specimens that require extra processing time
is small, it may be expedient to group all specimens together. However, when a substantial number of specimens require extra effort, it is usually necessary to stratify
specimens by the amount of work they required before
computing turnaround time. The author examined the
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AMERICAN JOURNAL OF CLINICAL PATHOLOGY
Special Article
turnaround time of 22,564 urine cultures from a single
institution using both a stratified and unstratified analysis. In an unstratified across-the-board analysis, there
was considerable specimen-to-specimen variation in
turnaround time (coefficient of variation = 81%) and no
identifiable turnaround time problems. Specimens were
then stratified into eight groups by computer, on the basis of test results (no growth, growth of rapidly growing
micro-organisms, growth of slowly growing microorganisms, etc). Specimen-to-specimen variation in turnaround time within strata was reduced by 44%, and a
laboratory problem processing positive cultures on
weekends was revealed.
Sample Size
The number of specimens required to make an accurate assessment of laboratory turnaround time depends
on the reason turnaround time is being measured. 5
When directors of a laboratory with good overall turnaround time wish to know if performance has fallen below standards, at least 500 specimens should be analyzed. When mean turnaround time in a problem facility
is being followed for signs of improvement, 100 to 200
specimens are usually adequate. Sample size requirements place a practical limit on how often turnaround
time ,can be monitored, and may make it difficult to
monitor turnaround time of low volume tests or of individual clinics or wards, because it is likely that the number of requests emanating from a particular location will
be too small to yield acceptable precision. The turnaround time of procedures that are processed on the
same analyzer may be lumped together to increase the
size of a sample. When quality control charts are used to
follow turnaround time, smaller sample sizes are typically required, but sampling is more frequent.
Computing Turnaround Time From Electronic
Databases
Collection and transportation time may be calculated
from data in a hospital or laboratory information system,
or by placing observers on wards or in the laboratory to
note the time milestones in the testing cycle are completed.4 The large databases found in modern medical
information systems often contain enough information
to generate laboratory turnaround time reports. 1318
These reports are easy to produce and typically include
large sample sizes, but they must be interpreted cautiously. Information relating to cancelled tests—which
may account for as many as 10% to 15% of records in the
database of large teaching hospitals—is often incomplete
and may produce nonsensical turnaround times that
skew summary statistics. In addition, computer databases do not generally contain accurate information
about tests that were ordered or completed while the
computer system was not functioning. Tests performed
during periods of computer downtime are often ignored
in automated reports, although turnaround time is apt to
be significantly lengthened. McConnell 12 studied blood
counts and electrolyte panels ordered from an emergency department, and found that average turnaround
times when the hospital computer was down were 47%
longer than when the computer was functioning properly.
In many hospital information systems, the time a test
report was issued is updated whenever the test result is
updated, erasing from the database any record of the
time the original report was completed. This can create
the impression that the test had an unusually long turnaround time, although the essential medical information
may have been communicated in a timely manner with
the report being modified to correct something as minor
as a spelling error or the initials of a technologist. As a
general rule, it is prudent to examine a histogram of computer-generated turnaround times for outliers and nonsensical values before relying on automated throughput
reports.
Consideration should also be given to the accuracy of
the information captured by the computer. The author
compared the accessioning time recorded in hospital information system to the time recorded by an observer
with a synchronized watch stationed in the accessioning
area. In one of the two hospital studied, stat electrolyte
and complete blood count specimens physically arrived
in the laboratory an average of 32 minutes before they
were accessioned into the computer. I9
Test Priorities
Normally, the turnaround time of "stat" tests is measured separately from tests ordered with other priorities.
Even within the priority called "stat," not all test requests carry the same medical urgency." Ambulatory
outpatients are typically not critically ill, and a stat request from an outpatient setting usually carries less urgency than a stat request from an inpatient setting. To
further complicate matters, some stat tests are ordered
for medical emergencies, while others are ordered for logistical convenience.I3-20"26 The implications of a delay
in completing "medical" and "logistical" stat testing are
quite different. Failure to rapidly report the result of tests
ordered in a medical emergency can cause patients
harm. These lapses properly fall within the purview of a
medical quality assurance program. In contrast, failure
to rapidly report results of stat tests ordered for logistical
A.J.C.P. -June 1996
VALENSTEIN
681
\d Time
reasons do not, by definition, threaten patients' welfare.
Yet they may compromise the efficiency with which care
is delivered, which may have important financial consequences in this competitive era. When monitoring turnaround time, it would be desirable to separate stat requests ordered because of clinical urgency from stat tests
ordered for logistical considerations. Unfortunately, this
is not practical.
Most hospital-based laboratories offer at least two priority categories ("routine" and "stat") for common hematology and chemistry tests, and many offer an intermediate level of urgency, which is variously called
"today," "rush," "priority," "as soon as possible," etc.
Gambino27 has divided turnaround time requirements
into four levels of urgency: immediate feedback, 15 minutes to 1 hour, same shift, and several days. Except in the
commercial sector, there has been relatively little interest
in monitoring turnaround time of non-stat tests. The
lack of attention to non-stat turnaround time is unfortunate, because there is compelling evidence that slow
turnaround time of routine tests increases the frequency
of stat and duplicate testing.45 The high proportion of
stat tests ordered in large hospitals may be due to the slow
turnaround time of routine tests in the same institutions.
Although emergency testing still represents less than 10%
of requests at community hospitals with fewer than 300
beds,28 stat specimens account for a substantial proportion of the total laboratory workload in large teaching
hospitals. In the late 1980s, stat requests accounted for
30% of hematology and chemistry tests at the University
of Alabama Medical Center in Birmingham,29 32% at
University Hospital in Stony Brook, NY, 36% at the
Hospital of the University of Pennsylvania,20 41% at
University of Western Ontario Hospital in London,30
and 45% at UCLA Medical Center.18 Currently, the proportion of tests that are ordered stat at teaching institutions is even higher.31
provement has led some facilities to concentrate on continually shortening their turnaround time, rather than
on where their current performance stands relative to expectations or peer institutions.
Expectations of Providers
Several surveys of clinicians and laboratory managers
have dealt with the question of how long a physician
should reasonably have to wait for test results32"34 (Table
2). Lundberg2 described the results of a series of meetings
between laboratory directors and clinicians that were designed to provide a consensus about appropriate turnaround time for commonly ordered tests at a single institution. Barnett and colleagues35 surveyed directors of 38
laboratories and found wide variation in turnaround
time standards for stat tests. Acceptable turnaround time
for stat serum electrolyte testing, for example, ranged
from 10 minutes to 2 hours. They also noted that criteria
for acceptable turnaround time were more stringent in
small hospitals, a relationship that has been observed by
others.8 This trend is surprising, because patients hospitalized in small institutions tend to be less ill than their
counterparts in large facilities, and presumably are less in
need of rapid reporting. Because laboratories in smaller
institutions do appear to be able to deliver faster turnaround time, it seems likely that clinicians' goals are influenced by the performance of their local laboratory.
Different types of providers appear to have different
turnaround expectations. In Murphy's survey of clinicians, minimally acceptable turnaround times were
found to be in close agreement with goals reported by
laboratory directors.36 However, Hallam reported that
internists' view of reasonable turnaround time for routine tests was much more demanding than that of laboratory directors, and that nurses wanted test results back
more rapidly than either of the two groups.
Medical Necessity
T U R N A R O U N D TIME GOALS
Five approaches have been used to establish turnaround time goals. Some facilities set their sights on customer expectations—the demands of physicians, nurses,
and, in a few instances, their patients. Other institutions
define goals in terms of medical necessity—responsiveness that is required by a patient's medical condition.
Some facilities focus on logistical necessity—the turnaround time required to move patients through emergency departments or intensive care units expeditiously.
Still others define goals in terms of what other laboratories are achieving—either the "average" laboratory,
"best performers," or the performance of major competitors. Finally, the concept of continuous quality im-
Vol. I
The disparity between physician's expectations and
laboratory performance in large teaching hospital raises
a central question: Is turnaround time too slow, or are
the expectations of physicians unreasonable? Several examples from the published literature and the author's experience illustrate how this question might be answered
in practice. A microbiology laboratory in a 500-bed
teaching hospital performed daily testing for Clostridium
difficile toxin on weekdays, but specimens that arrived
between Friday afternoon and Sunday evening were processed the following Monday. A review of specimens
with significant toxin titer showed that patients who sent
stool specimens on a weekend had longer delays before
•No. 6
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
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TABLE 2. MINIMALLY ACCEPTABLE TURNAROUND TIME REPORTED BY CLINICIANS
Hallam »
Hallam 8
Test Priority
Survey Group
AM Routine
Laboratory Directors
AM Rout ne
Internists
Turnaround Time Interval
Not Specified
Not Specified
Author
Enzymes (min)
CBC/Basic Hematology (min)
Crossmatch (min)
Glucose (min)
Gram Stain (min)
Coagulation (min)
Serum Electrolytes (min)
Author
Test Priority
Survey Group
Turnaround Time Interval
Enzymes (min)
CBC/Basic Hematology (min)
Crossmatch (min)
Glucose (min)
Gram Stain (min)
Coagulation (min)
Serum Electrolytes (min)
131
143
125
124
219
116
108
123
122
130
Murphy'6
Barnett4
Barnett"
Routine
House staff
Stat
Clinicians outside
of Laboratory
Receipt to
Reporting
150
100
Ordering to
Reporting
60
Stat
Directors of
Small
Laboratories
Collection to
Reporting
25
15
60
15
10
20
20
Stat
Directors of
Large
Laboratories
Collection to
Reporting
45
20
45
30
20
30
30
Hilborne34
30
120
140
60
Lundberg1
Howanitz32
Howanitz32
Howanitz33
Hilborne34
Stat
Clinicians and
Laboratory
Directors
Receipt to Report ng
Stat
Clinicians of
selected
specialties
Collection to
Reporting
Stat
Laboratory
Directory
Stat
Laboratory
Directors
Stat
House staff
Collection to
Reporting
Receipt to
Reporting
10-20
60
Receipt to
Reporting
50
15
20-30
60
60
60
60
60
50
60
60
60
10-20
therapy was instituted, longer intervals of diarrhea, and
more lower gastrointestinal procedures than patients
who were tested on weekdays, all suggesting that clinician demands for more rapid weekend testing were justified.
A different picture was obtained in the author's review
of cerebrospinal fluid testing for bacterial antigens. These
tests are typically reported 1 to 2 hours after specimens
arrive in the laboratory. In none of the cases with positive
antigen tests did physicians change from empiric to specific antibiotic therapy before culture and susceptibility
results became available. A similar lack of physician response to rapid bacterial antigen test results has been reported by others.37 Because positive antigen test results
were not influencing therapy, there was no medical need
for rapid reporting. It is axiomatic that a test that is not
worth doing is not worth doing quickly.
For some tests, published reports on the benefits of
rapid reporting are contradictory. A recent randomized
study of rapid bacterial identification and susceptibility
testing showed that patients randomized to rapid testing
had shorter hospital stays and lower mortality than patients randomized to traditional testing.38 However, a
second study observed no significant differences in out-
60
30
30
come between patients who were randomized to rapid
versus traditional susceptibility testing.39
Logistical Necessity
The increased costs of rapid testing may be offset if
rapid reporting makes medical care as a whole more
efficient. The previously cited study by Doern and colleagues38 suggested that rapid microbiology reporting reduces the lengths of some hospitalization. Improving the
turnaround time of routine testing has been reported in
two studies to reduce the proportion of tests that are ordered on a stat basis.10'29 Rapid reporting of myocardial
injury markers is generally believed to result in more
efficient use of intensive care units. Even performing
tests stat for the convenience of clinicians—a practice
widely viewed in the laboratory as unnecessary and
wasteful—may in fact make overall economic sense if
it allows highly productive physicians to function more
efficiently.40
What are the relative costs and savings associated with
shortening turnaround time? From a cost-per-test perspective, rapid testing is expensive. Stat serum glucose
determinations processed individually are more than
three times as expensive to perform as glucose determi-
A.J.C.P.-Junc 1996
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Turnaround Time
nations run in batches of 10 specimens. 4 ' Although the
College of American Pathologists workload recording
system does not assign different weights to stat and routine testing, time-motion studies in the author's laboratory have shown that stat testing takes 30% to 200% more
technologist time per specimen than routine testing. The
cost of staffing a laboratory section at a level that will
guarantee stat reporting within a given time frame is
difficult to calculate, because laboratory workload is in
constant flux. Staffing a laboratory to accommodate
peak loads creates inefficiencies when workload is light.
Westlake41 has suggested that queuing theory provides a
conceptual framework for balancing the requirement to
provide timely service against the need to use employees
efficiently. Unfortunately, the theory is difficult to apply
in practice.
The incremental savings engendered by speeding turnaround time are as difficult to calculate as the incremental costs. Because neither the savings nor the costs are
likely to be known with much accuracy, it is rarely practical to explicitly compare the costs of providing more
rapid reporting with the savings achieved by making results available sooner to caregivers. To complicate
matters, the increased costs of speeding throughput are
likely to be reflected in the laboratory's or courier service's budget, whereas savings are likely to be reflected in
lower physician and nursing costs, which are typically
assigned to other departments or divisions.
benchmark contemporary laboratory performance, because the particular turnaround time interval being measured was frequently not specified. Reported turnaround
times vary dramatically depending on whether the postanalytic component of turnaround time is included. In
one institution that manually distributed outpatient reports, it took an average of 4.4 days to deliver results of
complete blood counts to outpatient clinics, and 27.3
days before the results were filed in patient charts. 43 Another study showed variation in reporting time for outpatients of 22 to 122 hours, with a median lag of 50
hours.
In 1990, the College of American Pathologists reported the first of several large multi-institutional studies
of laboratory turnaround time, as part of their Q-Probes
quality assurance program. The College's landmark
effort, led by Howanitz, Steindel, Zarbo, and others, enlisted the support of hundreds of laboratories that agreed
to systematically measure turnaround time using a common data collection instrument and set of definitions.
To date, Q-Probes turnaround time studies have examined responsiveness for chemistry, hematology, microbiology, autopsy, and surgical pathology procedures.45"51
Blood banking and cytopathology turnaround time studies are in development. Published results have provided
unparalleled information about turnaround time performance of many United States and some foreign laboratories. Selected findings are summarized in Tables 4-6.
Turnaround Times Observed in Practice
IMPROVING TURNAROUND TIME
Before 1990, there were few published studies of turnaround times achieved by hospital-based laboratories.
The editors of Medical Laboratory Observer conducted
regular surveys of turnaround time in selected institutions for a number of years.42 The intervals used to define
turnaround time in these studies varied between the surveyed institutions, with as many as nine different definitions being used by laboratories in the same survey.
Nevertheless, survey results supported several conclusions: (1) During the 1980s, laboratory turnaround time
improved in most institutions; (2) turnaround time in
larger hospitals (>300 beds) was slower than in smaller
institutions (< 150 beds); (3) the turnaround time expectations of clinicians and laboratory directors in large and
small hospitals paralleled laboratory performance—better laboratory responsiveness is expected in smaller institutions; and (4) turnaround times, achieved in practice
were usually longer than the expectations of clinicians
and laboratory directors.
Table 3 shows laboratory turnaround performance
reported in selected studies published before
1990.4J Il2-28-34 it is difficult to use data from the 1980s to
The current state of knowledge about how to improve
turnaround time is rudimentary. Much of our information is anecdotal, and a large proportion is unpublished.
To complicate matters further, the factor that appears to
be the single most important predictor of turnaround
time in every published study—institution size—is not
easily changed. Large hospitals consistently show poorer
responsiveness than their smaller brethren, yet reducing
hospital size to speed turnaround time is hardly practical. Nevertheless, some direction can be sought from
published studies and unpublished data that have come
to the author's attention.
Preparation of Turnaround Time Reports
The act of monitoring turnaround time appears, in
and of itself, to improve performance. Bloch13 described
a computer program that calculated mean laboratory
throughput for every hour of the day, and reported that
posting the report on a regular basis reduced overdue stat
tests by 45% in one institution. Significant reductions in
the proportion of overdue tests were also reported by Pel-
Vol. 105-No. 6
684
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
Special Article
TABLE 3. TEST TURNAROUND TIMES REPORTED IN STUDIES PUBLISHED BEFORE 1990
Hilborne'"
Kull28
Valenstein"
McConnell'2
Institution
UCLA inpatients
Several institutions
Turnaround time interval
Receipt-toverification
42000
Computer
Median
Stat: 89
Routine: 141
Stat: 39
Routine: 71
Varied among
institutions
Not specified
Not specified
Mean
Stat: 35
Routine: 180
Stat: 23
Routine: 150
Stat: 50
Routine: 165
Stat: 24
Routine: 160
Stat: 26
Routine: 120
Stat: 28
Routine: 155
SUNY Stony
Brook
Receipt-toVerification
39000
Computer
Median
University of New
Mexico
See Below
Author
Number of procedures
Data source
Summary statistic
Enzymes (min)
CBC/Basic hematology (min)
Crossmatch (min)
Glucose (min)
Coagulation (min)
Serum electrolytes (min)
Stat: 100
Routine: 122
Stat: 38
Routine: 122
lar and colleagues15 as a result of monitoring. Biweekly
feedback of a section by section turnaround time report
from a radiologic information system improved turnaround time in a radiology department.52 In the author's
laboratory, surgical pathology turnaround time reports
are circulated monthly to all pathologists. Reports show
aggregate and individual pathologist performance. After
the reports were circulated, collection-to-verification
turnaround time improved by 32%, and variation in performance between pathologists (standard deviation) was
reduced by 52%. Some of the improvement that comes
with posting turnaround time performance may be attributable to the Hawthorne effect.53 However, much of
the improvement is sustained over periods of many
501
Observation
Mean
Patient arrival to
collection: 78
Collection to lab
receipt: 13
Analytic: 57
Stat: 66
Barnett4
Community
Hospital
Collection-toReceipt
135
Observation
Median
Chemistry: 78
Hematology: 28
Post-analytic: 5.5
Stat: 48
months, when changes due to the Hawthorne phenomenon would normally begin to show extinction.
Total Quality Management
Total quality management refers to a process of analyzing components that contribute to product quality
and making systematic and progressive improvements in
each element.54 Seltzer and colleagues55 used a total
quality management approach to improve turnaround
time in a radiology department. After identifying factors
that were contributing to turnaround delays, the authors
began providing home computer terminals for case signout, implemented a buddy system for proxy signing,
TABLE 4. EMERGENCY DEPARTMENT TURNAROUND TIME PERFORMANCE (613 Laboratories)
Bottom 10% of laboratories
Median potassium completed in
90% of potassium tests completed in
Median hemoglobin completed in
90% of hemoglobin tests completed in
Median laboratory
Median potassium completed in
90% of potassium tests completed in
Median hemoglobin completed in
90% of hemoglobin tests completed in
Top 10% of laboratories
Median potassium completed in
90% of potassium tests completed in
Median hemoglobin completed in
90% of hemoglobin tests completed in
Order-toVerification (min)
Collection-toVerification (min)
Collection-toReceipt (min)
60
101
48
91
53
63
39
78
16
45
15
44
44
70
31
56
36
60
23
45
7
20
7
18
30
50
19
36
24
40
13
27
4
8
4
8
Adapted from Steindel and Howanitz (ref. 46).
A.J.C.P.-June 1996
VALENSTEIN
685
Turnaround Time
TABLE 5. TURNAROUND TIME OF SELECTED MICROBIOLOGY PROCEDURES
Percentile Rank of
Institutions
Characteristic
Number ot
Institutions
10th
50lh
90th
492
534
534
87
190
61.9
45
60
24.8
24
16
6.8
534
32
16
6
534
43
25
14
12
Cerebrospinal fluid gram stain, receipt-in-laboratory-to-verification (median, minutes)'
Respiratory specimen for mycobacteriology, collection-to-receipt (median, minutes)45
Mycobacterial smear, receipt-to-verification (median, hours)45
Mycobacterial culture, initial positive report, collection-to-verification (smear-positive
cases, median, days)45
Mycobacterial culture, initial positive report, collection-to-verification (smear-negative
cases, median days)45
Higher percentiles indicate better relative performance. For example, the number in the column labelled "10th percentile" indicates median turnaround time of the institution at the bottom
10th percentile. See individual references for descriptions of included and excluded cases.
eliminated the requirement for a cosignature from a fellow or resident, and teamed groups of radiologists with
specific transcriptionists. The mean time required to sign
reports decreased 59% from 26.0 ± 8.4 hours (mean ±
SEM) in the baseline period to 10.6 ± 2.9 hours. Bluth
and colleagues56 used total quality management techniques to reduce stat outpatient laboratory turnaround
time. They divided turnaround time into seven components, and used a Pareto diagram to highlight the components that were responsible for the largest fraction of
total turnaround time. Acknowledgment of results was
reported to be the longest single component (41 minutes), followed by specimen collection (36 minutes) and
transit time for the patient to travel to the laboratory
phlebotomy area (22 minutes). Interestingly, the analytic
phase of testing was reported to be the shortest of the
seven intervals (8 minutes). Process improvement led to
significant reductions in patient transit time (11 minute
reduction), laboratory check-in (11 minute reduction),
specimen transport to testing area (15 minute reduction), and acknowledgment of results (36 minute reduction). Overall, preanalytic delays were reduced by 76%
and the postanalytic delays by 88%. Waiting time for patients was reduced by an average of 62%.
Automated Specimen Transport
Two types of automated transport systems used in
clinical laboratories have been reported to improve test
turnaround time. Computer controlled pneumatic tube
systems are capable of carrying payloads up to 15 pounds
at speeds of 25 feet per second. The use of a pneumatic
tube system decreased the median collection-to-verification turnaround time for potassium and hemoglobin
results on specimens from the emergency department by
25%. 57 Steindel and Howanitz 46 compared emergency
department collection-to-verification turnaround time
of 21 institutions before and after the addition of a pneumatic transport system. Median turnaround time decreased by 8 minutes, and the 90th percentile specimen
turnaround time decreased by 11 minutes. Adding or
improving an existing mechanical transport system was
responsible for more improvement in turnaround time
than any other change examined, including moving the
stat laboratory closer to the emergency department. In
the same study, the particular location of the tube station
appeared to be an important predictor of turnaround
time. The 146 laboratories that reported having conveniently located stations had median turnaround time
that was 10% faster than the 27 facilities that reported
having inconveniently located stations.
Within some laboratories, commercially available automated track-based systems transport racks of specimen tubes at speeds of 10 feet per second. When combined with specimen bar code labelling and robotic
stations, track-based systems have been reported to significantly reduce within-laboratory processing time. AC-
T A B L E 6. TURNAROUND TIME OF SELECTED ANATOMIC PATHOLOGY PROCEDURES
Percentile Rank of
Institutions
Characteristic
47
Surgical pathology routine specimen, collection-to-case sign-ofFturnaround time (median, days)
Surgical pathology routine specimen, collection-to-report delivery, small hospitals (median, days)41
Surgical pathology complex specimen, collection-to-case sign-offturnaround time (median, days)4'
Autopsy, time of death to beginning of prosection (median, hours)50
Autopsy, start of prosection to preliminary report release (median, days)5'
Vol. 105-No. 6
Number ot
Institutions
I Oth
50th
90th
525
144
489
452
418
2
4
3
17.1
3
1
2
1
3.5
1
1
1
1
1
0
686
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
Article
counts to date have been anecdotal. Fully automated
track-based/robotic transport systems are expensive,
typically costing in excess of $ 1 million per installation.
The high cost makes the systems most suitable for high
volume commercial or reference laboratories.
Regional, Decentralized, and Point-of-Care Testing
The transfer of testing out of centralized hospital laboratories and into decentralized "stat" laboratories or
bedside analyzers has, to a large measure, been driven by
demand for more rapid test results. The improvement in
turnaround time afforded by decentralized and point-ofcare testing has been reviewed elsewhere. The opposing
trend—movement of tests into regional and state laboratories—is being driven by a desire to reduce costs, and
the adverse impact of this trend on turnaround time has
received less attention. Schifman and colleagues45 studied the consequences of regional testing on the turnaround time of mycobacterial test results. Concentrated
smear results were reported a median of 24 hours after
laboratory receipt when performed in an on-site testing
facility, but after 48 hours when performed in private
commercial laboratories and 91 hours when performed
in state-owned public health laboratories. Similarly, positive cultures were reported after a median of 20 days
when performed on-site, but 28 days when performed
by public health laboratories. Laboratory managers who
aim to reduce test turnaround time should carefully scrutinize the responsiveness of their reference facilities.
Computer-Eased
Interventions
The impact of computers on turnaround time has
been mixed. There is general consensus that the post-analytic phase of the test cycle—distributing clinical information to providers—has been revolutionized by clinical information systems. The impact of hospital and
laboratory information systems on pre-analytic and analytic turnaround time has not been uniformly positive.
In a large study of pre-analytic and within-laboratory
turnaround time of emergency department testing, institutions that used hospital and/or laboratory computer
systems had longer median and 90th percentile turnaround times than their counterparts without information systems. Interpreting this observation is problematic. Larger hospitals, as a group, tend to have longer
turnaround time, but are also more likely to use hospital
and laboratory information systems.
Several anecdotal reports suggest that one computerbased intervention has had a consistently positive effect
on within-laboratory turnaround time: autoverification.
The term autoverification refers to a process in which a
laboratory computer system automatically verifies and
releases laboratory results sent from an interfaced automated analyzer, when the results meet certain parameters. Most commonly, results are autoverified when they
fall within a normal or near-normal range. Autoverification has been reported to reduce median stat intra-laboratory turnaround time by 5 to 10 minutes in several
institutions, and has been reported to reduce the 90th
percentile within-laboratory stat turnaround time by 10
to 15 minutes.
Another computer-based development that has been
reported to reduce turnaround time is automated tracking of overdue results. Several anecdotal, unpublished
reports suggest that on-screen reminders of overdue stat
results and printed lists of overdue routine results will
significantly shorten 90th percentile turnaround time.
Overdue test reminders generally do not shorten median
turnaround time.
Managing
Expectations
One approach to dealing with turnaround time deficiencies is to modulate demand for faster service. Because most physicians' turnaround time expectations are
not grounded in clinical necessity, it may be expedient to
try to change clinicians' expectations as well as laboratory performance. Along these lines, approximately half
of surveyed laboratories reported that they distribute
guidelines to physicians about how long particular tests
should take to complete. I0 Benzra58 asked a panel of laboratory managers to name the intervention that had the
most positive impact on turnaround time complaints,
and 27% indicated that communicating with doctors,
nurses, and clerks about reasonable turnaround expectations was the change that produced the most impact.
CONCLUSIONS
From the forgoing discussion, it is apparent that laboratory turnaround time can be measured in various
ways, and that different methods for measuring turnaround time produce a different picture of laboratory
performance. Early measurements of turnaround time
focused on different intervals of the testing cycle, used
different summary statistics, and were not directly comparable to one another. In the past 5 years, turnaround
time performance has been measured at a large number
of institutions using a standardized approach promulgated by the College of American Pathologists, and we
currently have a reasonable idea how long institutions of
varying size take to collect, transport, process, and report
test results. In both early and recent studies, the perfor-
A.J.C.P. •June1996
VALENSTEIN
Turnaround Time
mance of most laboratories has not met the expectations
of clinicians.
The disparity between clinicians' turnaround time expectations and actual performance, particularly in large
teaching hospitals, suggests either that laboratories are
failing to meet their responsibilities to patients or that
expectations have been developed without a critical appraisal of the performance necessary for good care. Our
limited knowledge about the relationship between turnaround time and patient outcome prevents us from
choosing the correct explanation, and should serve as a
warning to those who would plunge too quickly into setting turnaround time standards for laboratory accreditation.
The assumption that faster laboratory turnaround
leads to more efficient care is equally problematic. In
some settings this relationship undoubtedly holds true,
but in many cases the costs of providing faster service
and the savings resulting from faster service are not
known. We can reasonably expect this area to receive
sustained attention in the future, as the increasingly
competitive medical marketplace drives institutions to
critically examine the efficiency of their operations. Presumably, within the next 5 years, we will have a better
understanding of how much improvement in turnaround time can be expected from automated transport
systems, point-of-care testing, and other technological
advances, how much these improvements are likely to
cost, and whether efficiencies in patient care will result.
As we learn more about the costs and benefits of shortening laboratory turnaround, we can expect to discover
settings in which the cost of speeding laboratory throughput is greater than the derived benefit. We recognize that
increasing analytic accuracy beyond certain limits does
not increase the clinical usefulness of a laboratory result.59 Similarly, increasing the speed of laboratory turnaround beyond certain thresholds probably has little
effect on clinical decision-making, and may in fact increase the frequency of laboratory errors. Augustus Caesar, whose quotation opened this review, recognized the
risks of recklessly pursuing speed at all costs. Although
he extolled the virtue of being swift, he also cautioned his
contemporaries to "make haste slowly" (festina lente).
The laboratory community should keep this admonishment in mind.
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