A Computerized Word-processing and Data System for
Histology in a Private Medical Laboratory
CHARLES T. ASHWORTH, M.D., THOMAS H. McCONNELL, M.D., CARL NIELSEN, B.A.,
ROBERT D. ASHWORTH, PH.D., AND JAYE SANFORD, H.T.(ASCP)
Ashworth, Charles T., McConnell, Thomas H., Nielsen, Carl,
Ashworth, Robert D., and Sanford, Jaye: A computerized
word-processing and data system for histology in a private
medical laboratory. Am J Clin Pathol 71: 257-262, 1979.
This report describes the use of a word-processing microcomputer, the Lanier Text Editor, for preparation of surgical
tissue reports. Gross and microscopic description formats
are stored on floppy disks, which may easily be completed
and edited on a cathode-ray tube (CRT) for rapid computerized printing. Also described is the use of a PDP 8/E minicomputer for entry, storage, and manipulation of historic,
demographic and diagnostic data, printing of numeric and
alphabetic listings, cross-indexing of cases by diagnosis, and
the accumulation of data for direct patient or physician billing.
(Key words: Word processor; Text editor; PDP 8/E minicomputer; Histology; Tissue historic files; Tissue reports;
Private laboratory.)
BECAUSE OF the increasingly large volume of results
that it generates, the clinical laboratory (compared
with, for example, the anatomic pathology laboratory)
has been a major target for computerization in the
medical laboratory.7 In another report we described
a computer software package for data handling and
report generation in diagnostic cytology,1 and in this
report a computer system for histology is described.
The number of individual tissue reports issuing from
a department of surgical pathology may be small compared with that from the clinical pathology laboratory.
However, their greater length and complexity, the need
for descriptive and interpretive verbalization, and the
necessity for filing and cross-indexing of data for ready
accessibility are some of the problems that must be
faced in undertaking the application of the computer
to histology. One of the first efforts toward solving
these problems was the development of a coding system for diagnosis, providing uniformity in terminology.
This culminated in the development of the Standardized
Nomenclature of Pathology (SNOP)3 and more recently
the Standardized Nomenclature of Medicine (SNOMed)4
under the auspices of the College of American Pathologists. A few reports of computer filing and listing of
Received February 3, 1978; received revised manuscript and
accepted for publication May 25, 1978.
Address reprint requests to Dr. Ashworth: 3434 Swiss Avenue,
Dallas, Texas 75204.
Diagnostic Pathology Laboratory and Department of
Pathology, University of Texas Southwestern
Medical School, Dallas, Texas
coded diagnoses followed the development of SNOP.3"
Computerization of work-load record keeping has also
been described, after the introduction of a laboratory
work-load recording system by the College of American Pathologists.2 The memory typewriter* has been
used extensively for stored specimen descriptions in
the last few years. More recently, microcomputers
dedicated to word processing have become available
for report preparation. The combined use of such a
word-processing minicomputer and a PDP 8/E computer)" for handling the data load in the tissue department of our private laboratory is the subject of this
report.
Methods
The presentation consists of (1) a description of the
word-processing facility for report preparation and
(2) a description of the software package for historic
filing of surgical pathology reports, case listings, and
the compilation and printing of work activity data and
statistics in the department of surgical pathology.
Tissue Report System
Tissue reports are prepared with the LTE-2D (Text
Editor). This is a microcomputer and printer that functions as a word processor.:): It consists of a central
processing unit, a cathode-ray tube (CRT) for data
entry and display, a twin-disk drive with interchangeable "floppy disks" for data storage, and a "Daisy
Print" wheel printer (Fig. 1). A word-handling and
formating program is permanently installed in "read
only memory" (ROM). Data are entered by keyboard
onto the CRT for display, editing, and storage. The
user is enabled to store formated word compositions
* IBM, 909 Third Avenue, New York, N. Y.
t Digital Equipment Corporation, Maynard, Mass.
t Lanier Business Products, Inc., Atlanta, Ga.
0002-9173/79/0300/0257 $00.80 © American Society of Clinical Pathologists
257
258
A S H W O R T H ET AL.
FIG. 1. The Lanier Text Editor (LTD-2): keyboard for data entry,
CRT for viewing text, printer, and microprocessor unit with twin
drives for floppy disks.
on floppy disks. The text of each composition is stored
in one of 128 segments of a disk, each segment having
a storage capacity of approximately one single-spaced
typewritten page. These stored text units are instantly
recallable for review, additions, deletions, and reformating. For these purposes, upon keyboard entry signal, the stored text is displayed on the CRT screen.
After revision, the composition may be printed out or
reassigned to storage for later printing or other reuse.
The storage capacity for descriptive formats is essentially unlimited, because any number of the easily
changed and inexpensive floppy disks may be used.
Storage capacity and text manipulation of stored data
are enhanced by the use of two disk drives, but one
disk drive may be sufficient for some situations.
Word, letter, sentence, or paragraph deletions or
corrections are easily achieved by keyboard operation
while the composition is under view on the CRT screen.
A cursor, which is under keyboard control, facilitates
additions, deletions, and alterations in the text. Reformating of the data, including shortening or lengthening of the print line, and single or multiple line spacing are also functions that may be accomplished readily
by keyboard manipulation. The right margin of the
text can be justified instantly prior to final printing.
The printer is a "Daisy Print" wheel type, with typewriter-quality print. A wide variety of print styles is
available by use of exchangeable print wheels. It prints
A.J.C.P. • March 1979
at the rate of 540 words per minute, operating with
precision, low noise, and minor vibration. The printer
can handle individual paper forms, or with a line-feeder
device it prints on continuous interfold paper. The
delivery of typed characters is precise, and there is
complete freedom from irregular letter spacing and
letter overlap, which may occur with high-speed manual
typing. Editing of text on the CRT screen compjetely
eliminates erasure problems on both original and copy
sheets.
Our tissue reporting system is based upon the integrated use of (1) the Text Editor; (2) a permanently
installed network dictation system^ with three central
storage tapes, each of which is connected to the gross
examination area, two pathologists' offices, and two
secretarial stations; (3) the availability of an unlimited
number (currently approximately 150) disk-stored
gross and microscopic description formats that are
available on the Text Editor. These descriptions can
be displayed on the CRT for additions, deletions, and
revisions (Figs. 2 and 3). The description formats were
prepared by two of us, using our previous surgical
pathology descriptions for reference. Each description contains "stops" at designated locations, which
are readily accessible by cursor control for revision of
text. However, revisions can also be made at any location in the text. The secretary-operator simultaneously
manipulates the CRT keyboard, receives by earphone
the additions or corrections dictated by the pathologist,
and executes their application to the designated stored
description formats.
Provisional printouts of gross descriptions are prepared by the secretary-operator on one-part continuous interfold paper. This expendable copy is available to the pathologist when microscopic slides are
studied. After microscopic study and changes or additions to the stored microscopic descriptions are made
and dictated by the pathologist, the secretary-operator
recalls the gross description, which was stored earlier,
and appends and edits the microscopic description,
comment, if any, diagnosis, and SNOP codes. The
completed description is then stored at a designated
location on a floppy disk in the Text Editor. After one
or several cases have been stored, printing of the final
reports is begun on continuous interfold report forms
37-1
GROSS DESCRIPTION:
I t measures
The tumor mass from the breast i s f i r m , encapsulated and s p h e r o i d .
I.
The outer surface of the mass i s smooth and sharply demarcated. Sections
reveal homogeneous, g l i s t e n i n g f i b r o u s - l i k e t i s s u e which i s rubbery in c o n s i s t ency and n o n f r i a b l e . Small punctate pink nodular f o c i and small c l e f t s are
v i s i b l e in the tumor t i s s u e . 8 .
FIG. 2. Example of stored gross description for fibroadenoma of breast. The symbol "<8>" indicates presence of tab stops in the description
at which locations additional descriptive text may be added. Words, phrases, sentences or the entire paragraph can be easily deleted and
replaced at any location in the description.
COMPUTER SYSTEM FOR HISTOLOGY
Vol. 71 . N o . 3
259
37-3
MICROSCOPIC EXAMINATION:
Sections show the nodular l e s i o n to have a f i b r o u s composition and i t c o n t a i n s
numerous e p i t h e l i u r n - l i n e d ducts and t u b u l e s . The l i n i n g c e l l s are doublelayered and cuboidal to columnar-shaped. The c e l l s are w e l l - d i f f e r e n t i a t e d and
no a t y p i c a l i t i e s are found. The ductal s t r u c t u r e s c o n t a i n i n t r a - c a n a l i c u l a r
p r o t r u s i o n s of the surrounding f i b r o u s t i s s u e producing i r r e g u l a r p a t t e r n s . The
f i b r o u s component of the l e s i o n i s moderately c e l l u l a r and c o n t a i n s looser
areas of myxoid c o m p o s i t i o n . The outer margin of the l e s i o n i s w e l l - d e f i n e d
i n d i c a t i n g encapsulation of the l e s i o n . 8 .
DIAGNOSIS:
EXCISION OF TUMOR MASS FROM 9 BREAST:
FIBROADENOMA.
A-M:dkm
T0401 M9010
Drs.
Ashworth and McConnel 1
P i c . 3. Example o f stored microscopic description for fibroadenoma o f breast w i t h diagnosis, topographic and morphologic codes and
signature are included for editing. The location of the symbol " ® " at the end of the microscopic description provides an opportunity to
append additional microscopic description, enter a new paragraph of description, or add a comment after the description.
and continues automatically. While printing is going
on, processing of other reports on the CRT screen
proceeds concurrently. As many as ten carbon copies
may be clearly reproduced in the printed report. Dictation-reception, CRT data manipulation and editing,
recall and storage of report formats from computer
memory, and printing of reports are an integrated operation that the skillful secretary, after a brief period,
is able to organize and execute quickly and efficiently.
Our medical secretary, who had had no prior experience with computers, achieved a high degree of efficiency after a week of instruction and experience.
Condensed as well as the complete versions of the
stored gross and microscopic description formats are
available for reference at the pathologists' work stations. After a brief period of adjustment, descriptive
comments by the pathologist become easier, and an
efficient pattern of examination coordinated with dictation is quickly established.
Each of the stored descriptions contains one or more
"stops" where site, measurements, color, consistency,
extent of specific lesions, etc., or variations in microscopic features may be added to the descriptions. Microscopic descriptions may be varied in composition or
eliminated completely according to the philosophy
of the pathologist. Comments relating to extent of
disease, completeness of surgical removal, prognosis,
suggestions for diagnostic procedures, etc., can be
incorporated in the stored formats, substituted for or
added to the microscopic descriptions as desired. An
example of a completed tissue report is shown in Figure 4.
Use of the Technicon Ultra®,§ by rapid tissue processing under vacuum, enables tissues to be reported
twice daily in our laboratory. Use of the Text Editor
in the manner described above facilitates a rapid turnaround schedule for tissue-report generation twice daily.
§ Technicon C o r p . , T a r r y t o w n , N . Y .
In addition to the use of modified stored descriptions
as the source of reports, the Text Editor has proven
effective for transcribing de-novn descriptions, which
are necessary in those cases for which stored description formats are not available or applicable.
Data Storage and Listings
The second component of the procedure for handling
tissue data is the establishment and maintenance of
PATIIOLOCr RtPORT
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A.26
PATIENT NAME
Doctor Name
tutm %-• S77-08567
S^K/mtm StdmOtd.- cervical biopsy
€t&£*tTXmfm*4U
class
m
papi
C 77-*4787
The cervical biopsy consists of three snail tan mucosal tissue pieces. These
•easure fron 3 to 5 mm. In maximum dimension. The mucosal surfaces are smooth
and grayish white to tan. The cervical stroma Is firm and fibrous. Mo focal
lesions nor f r i a b l e areas are found. The entire specimen Is submitted for step
sections and histological study. A-H:dk»
MICROSCOPIC EXAMINATION:
The cervical biopsy M t e r l a l reveals covering s t r a t i f i e d squamous epithelium
over most surfaces. Focal areas of atypical squataous epithelium are noted In
which epithelial thickening, hyperplasia In the basal cell layer and nuclear
enlargement with pleonorphism can be seen. The atypical H i e s are most marked
In the deeper layers, but the c e l l s mature and cornlfy at the surface. No
stromal Invasion Is present In the leslonal tissue. The lesion f u l f i l l s the
c r i t e r i a of mild precancerous dysplasia of the kollocytotlc atypla type.
Slight chronic Inflammation Is present In the cervical stroma.
COjtCNT: Comparison of the c e l l s of the atypical lesion wl th the abnormal
c e l l s of the recent cervical cytology show the atyplsm to be of similar
nature and the atypical cytology findings are adequately explained by the
demonstrated lesion.
DIAGNOSIS:
CCRVIGAL PUNCH BIOPSIES: »ALL FOCAL AREA OF HILO PRECANCEROUS SQUAMOUS
EPITHELIAL DYSPLASIA. KOILOCYTOTIC ATYP1A TYPE. MODERATE CHRONIC
CERVICITIS.
A-M:dkm
T8300
M7601 M4300
Drs. Ashworth and McConnel 1
FIG. 4. Example of completed report typed by the Text Editor.
Stored gross and microscopic examinations with comments were
used in the preparation of this report.
260
A.J.C.P. • March 1979
ASHWORTH ETAL.
TISSUES PROCESSED
BY TECHNOLOGIST
WITH TECHNICON
ULTRA, AM AND PM
ACCESSION
OF CASES
MICROSLIDES TO
PATHOLOGIST,
AM AND PM
GROSS DESCRIPTION
BY PATHOLOGIST,
AM AND PM
GROSS EDITED
BY SECRETARY WITH
TEXT EDITOR, AM
AND PM
REPORTS
DELIVERED
MICRO DESCRIBED
BY PATHOLOGIST,
AM AND PM
MICRO EDITED
AND ADDED TO
REPORTS
-) PRINTED
GROSS BY
AM AND PM
SECRETARY WITH
TEXT EDITOR
DISPOSABLE COPY
3I OF EDITED GROSS
TO PATHOLOGIST
BILLS PRINTED
AND SENT
COPY OF REPORT
TO CRT FOR
ENTRY IN PDP 8
CHARGE DISK
7TC
DAILY NUMERIC
LISTING OF CASES
ALPHABETIC
LISTING OF CASES
CURRENT MONTH,
DAILY UPDATE
COMPUTER PROGRAM
TRANSFERS DATA
TO STORAGE DISKS
ALPHABETIC
LISTING OF ALL
CASES, MONTHLY
UPDATE
HISTORICAL DISK
DATA ENTERED
IN PDP 8E VIA
CRT BY CLERKOPERATOR
COPY OF
REPORT FILED
PERMANENTLY
IN DEPARTMENT
FIG. 5. Flow chart showing integration of the various activities of the computer program for histopathology.
alphabetic and numeric computer files of patients with
availability of cross reference by diagnosis, tissue site,
or referring physician. This portion of the computer
program is also integrated with charging, statement
printing, and activity summary reports for the tissue
laboratory (Fig. 5). A PDP 8/E computer has been
programmed in DIBOL language by one of us to handle
data on tissue reports. Data are entered daily via CRT
using file copies of the reports as the source of information. This entry provides data to the PDP 8/E for historic
data filing, activity summary reports, and for charging.
Figure 6 reveals the CRT screen format on which these
P a t i e n t ' s Name:
Doctor's Name:
P a t i e n t ' s Age:
Doctor's Account Number:
Tissue Number:
Charge Code:
Pathologist's Code No:
Amount Charged:.
Topographic Code:
Morphological Code:
P a t i e n t ' s Address ( I f Charged):
FIG. 6. CRT format for entry of tissue data. The data are entered
into a foreground mode for later computer transfer to historic
storage disks and charging disks.
data are entered. At the present time, the Text Editor
and PDP 8/E are entirely independent units, and data
from one cannot be transmitted to the other except
by re-entry on the CRT. Eventually, by interfacing
the Text Editor with the PDP 8/E computer, we hope
to be able to transfer data for billing directly from the
word processor to the PDP 8/E, eliminating the need
to re-enter demographic data on the computer's CRT.
Patient data with SNOP codes for topography and
morphologic diagnosis are entered daily by a foreground
entry program. Entry time is about 15 min for an average
of 40 cases each day. The data from the foreground
are transferred to the "tissue historic" storage disk
and then to "charge disks" for direct patient billing
and for doctor or hospital charges. Statements are compiled and printed from the storage disks. The information on the historic disk is stored for one year (the
capacity of the storage disk). From the historic disk
daily numerical listings of all of each day's cases with
complete patient data, anatomic sites and morphologic
diagnoses are printed on a line printer (Table 1). The
daily numeric lists are filed consecutively in a "Daily
Entry Ledger for Tissues" and are kept permanently.
An alphabetic listing of all cases from the first of the
current month, with anatomic sites and morphologic
diagnoses, is also printed daily for updating from the
historic disk. At the end of each month, all previous
tissue cases on the historic disk (one year) are printed
261
COMPUTER SYSTEM FOR HISTOLOGY
Vol. 71 . No. 3
in a monthly updated alphabetic listing. The daily
"month-to-date" and monthly "year-to-current month"
alphabetic listings serve as the main sources for historic
search, which is carried out in newly accessioned
cases. Previous year's files are consulted also as indicated in individual cases. The computer-produced
files and the carbon copies of tissue reports, which
are kept in book-bound form in numeric order, are
the only historic and cross-index files that are maintained in ourtissue laboratory. The computer-produced
files have effectively replaced all previous card index
files.
From the charge disks, our DIBOL software also
accumulates data on the numbers and types of tissue
examinations and CAP work units2 that are performed
each month in the department of histology. A year-todate summary of these figures is also accumulated.
The data are printed out monthly as part of an activity
summary for all departments of the laboratory. The
program also determines and prints increases or decreases in volumes of individual tests and the percentages of changes from the preceding months.
Results
Introduction of the Text Editor in our laboratory
has produced a major impact upon work flow and capacity. Report generation has been significantly facilitated and speeded up; total man-hours necessary for
report preparation have been decreased by approxi-
mately 50%; the meeting of deadlines for report delivery is much improved. Using the Text Editor, one
secretary-operator can produce 60-70 reports daily
(peak loads in our laboratory) without undue strain.
The requirement of seemingly incessant dictation
and transcription has been almost abolished, and the
atmosphere of work under the pressure of volume,
time, and deadlines changed favorably and dramatically almost immediately when the system was activated. For the pathologist, gross and microscopic
descriptions are much easier and take less time, and
examination can be carried out more reflectively without the harassments of voluminous dictations, grammar, and punctuations. In our tissue practice approximately 85% of all cases can be reported using edited
stored descriptions in both gross and microscopic
study. At least 50% of the cases are sufficiently predictable that a preliminary total (gross and microscopic)
description may be ventured, pending confirmation on
microscopic examination. Since the entire text of a
ventured microscopic description can be extensively
revised or entirely deleted and replaced with ease on
the CRT screen, there is no disadvantage in venturing
a completed gross and microscopic description on such
lesions as lipomas, epidermoid cysts, dermatofibromas, vas deferens segments, fallopian tube segments,
hemorrhoids, intradermal nevi, skin tags, acute appendicitis, normal appendix, and chronic cholecystitis
with or without cholesterolosis and cholelithiasis,
among numerous examples.
Table I. Portion of a Daily Numerical Listing of Tissue Entries with Patient and Doctor Data
and SNOP-coded Diagnoses*
TISSUE H I S T O R I C --1977—NUMERIC
Tissue #
Dale
NAME OF PATIENT
NAME OF DOCTOR
S08426
10/27/77
INGER, MARTIN
RUSSELL GRAHAM, M.D.
67
SKIN OF FACE
KERATOSIS. SOLAR
S08427
10/27/77
QUEAT, JEANNE C.
DR. SYD JACKSON
33
SKIN OF BACK
NEVUS, INTRADERMAL
NEVUS, INTRADERMAL
NEVUS. INTRADERMAL
S08428
10/27/77
BILDERBALD, JUANITA
DR. P. C. BURR
49
TOOTH, NOS
CARIES, NOS
TOOTH, NOS
INFLAMMATION, CHRONIC
S08429
10/27/77
SANTOZ, ENCARNACION
B. J. QUEEN. M.D.
42
FALLOPIAN TUBES. NOS
NORMAL MORPHOLOGY
S08430
10/27/77
McDOUGLAS, JO ANN
G. HALBERT, DO
21
APPENDIX, NOS
ACUTE INFLAMMATION
S08431
10/27/77
RIPPLE, MARTHA
T. F. ABBEY, M.D.
45
ENDOMETRIUM
HYPERPLASIA, CYSTIC, NOS
ENDOMETRIUM
HYPERPLASIA, ADENOMATOUS
* This listing is printed daily and filed in a binder to constitute the daily entry ledger for
tissues. Names of patients and doctors have been altered for publication. An alphabetic
AGE
TOPOGRAPHIC DESCRIPTION
MORPHOLOGIC DESCRIPTION
listing is also prepared for the historic data with frequent updating lo serve as the major
source of patient data retrieval.
262
A.J.C.P. • March 1979
ASHWORTH £7//iL.
Discussion
There is a trend toward more concise descriptive
surgical tissue reports. This is partly due to increased
numbers of surgical tissues, resulting in difficulties in
maintaining rapid turnaround of transcription and
typing. While pragmatism and directness in descriptive tissue reports are to be commended, the inclusion
of all clinically pertinent data is an irreducible minimum for acceptable pathology reporting. Carefully
designed computer-stored descriptive formats to be
completed with specified observations can, we believe,
effectively aid in fulfilling these requirements. The
content of the stored comments can, of course, and
should be designed by the pathologist-user to reflect
his own concepts of effective descriptive tissue reporting. The system we have described can be adapted
to eliminate microscopic descriptions if desired; or
comments on clinically pertinent aspects of the lesion
can be substituted for the microscopic description.
In our use of the system, where indicated, we have
included a comment section to follow the microscopic
description. Comments readily lend themselves to
stored formats, which save time by containing bibliographic references and established clinicopathologic
concepts that otherwise may require searching through
files or texts.
The system produces concise but complete descriptions that are typed with precision, grammatically
correct with proper punctuations and correctly spelled
words, and their content is lucid and readable because
of their premeditated and edited composition. Compared with the memory typewriter, which we had previously used, the Text Editor provides a considerably
greater flexibility, has wider applicability, and produces an edited report of higher quality.
The computer program for historic files has eliminated any need in our laboratory for an alphabetic card
index, which heretofore has been so time- and spaceconsuming in upkeep, difficult to use, and frustrating
because of frequent inability to locate records. The
daily printout of current month-to-date alphabetic
listings has kept us up to date, so that even in cases
of re-excision of a cutaneous lesion a few days after
the primary excision or biopsy, the patient's name and
record may be readily found and correlated with the
current tissue study. Since the tissue historic disk contains all pertinent patient demographic and diagnostic
data and can be sorted in a variety of ways, the problem of cross-indexing of tissues has been greatly alleviated. The historic disk can be sorted at any time to
produce a printout of any type of lesion at any topographic site. This printout contains all patient demographic and diagnostic data.
We are currently exploring, from the standpoints
of cost, efficiency, and convenience, the possibility
of filing the complete text of surgical tissue reports
on floppy disks or other forms of storage disks. Temporary or permanent storage by this means may prove
effective and would eliminate the costly and spaceconsuming bound volumes of surgical tissue reports.
It would also avert periods of time when report copies
are not available while they are at the bindery. Reports
could be reprinted from this disk-stored form in minutes, or they could be almost instantly viewed on the
CRT screen.
The system we have described has been completed
and in operation for only a few months at this time
and is still in the formative stages of development.
However, we are already convinced that it has increased the efficiency of operation and the quality of
reports prepared in our histopathology department.
Acknowledgments. Mary Lee Bryant, business manager, and
Diana K. Mitchell, medical secretary were responsible for development of the operational program of the Text Editor. Sherry Hoskins,
of the Lanier Corporation, provided instruction.
ADDENDUM
After submission of this manuscript, a description of a
computer program for preparation of reports and data retrieval in anatomic pathology was published by R. D. Aller
and others (Aller RD. Robboy SJ, Poitras JW, et al: Computer-assisted pathology encoding and reporting system
(CAPER). An on-line computer system developed at the
Massachusetts General Hospital. Am J Clin Pathol 68:715720. 1977).
References
1. Ashworth CT, McConnell TH, Ashworth RD, et al: A computer
program for cytology in a private laboratory using a PDP
8/E minicomputer. Am J Clin Pathol (in press)
2. College of American Pathologists. Laboratory Workload Recording Method. College of American Pathologists, Skokie,
111., 1977
3. College of American Pathologists. Systematized Nomenclature
of Pathology. College of American Pathologists, Chicago,
111., 1969
4. Cote RA: The SNOP-SNOMED concept: Evaluation towards
a common medical nomenclature and classification. Pathologist 31:383-389, 1977
5. Enlander D, Durbridge TC: Evaluation of SNOP coding of
pathologic data for computer retrieval. Lab Med 10:400401. 1969
6. GantnerGE: History of coding. Pathologist 31:390-397. 1977
7. J. Lloyd Johnson Associates, Achieving the Optimum Information System for the Laboratory. J. Lloyd Johnson Associates,
Northbrook, III., 1975