THK AMERICAN JOURNAL OF CLINICAL PATHOLOGY
Vol. 43, No. 5
Copyright © 1965 by The Williams & Wilkins Co.
Piintei in
U.S.A.
T H E STATUS OF ROUTINE BLOOD TYPING WITH T H E AUTOANALYZER
PHILLIP STURGEON, M.D., AND DOROTHY T. McQUISTON, M.T.(ASCP)
National Research Laboratory, The American National Red Cross, Los Angeles 6, California
The original report by McNeil and coworkers2 and subsequently those from this
laboratory demonstrated the applicability
of the continuous flow principle of the AutoAnalyzer* to the automatic detection of
hemagglutination reactions. 3 ' 4 Specific cell
and serum reactions were obtained with
bloods of types A, B, and 0 , as well as with
the weakest A2B. Similarly, with the use of
enzyme treatment and the addition of
inacromolecular media to the agglutinating
system, D-positive, including the lowest
grade D" types, yielded positive reactions
without the antiglobulin technic.3 This remarkable sensitivity has been amply confirmed in Kidd and Duffy typing by Allen
and associates.1
In the AutoAnalyzer, hemagglutinating
circuit streams of antiserum and of cell suspension are brought together and mixed.
As the mixture progresses through the circuit, reaction takes place, and agglutinates,
if formed, sediment and are selectively removed by decantation. A stream of distilled
water is then introduced to hemolyze the
remaining cells; the resultant hemoglobin
concentration is measured in a continuous
flow colorimeter and recorded automatically
as a (racing. The extent of the reaction is
determined by reduction in peak height in
the case of cell typing, and in plasma typing
by the extent of valley formation in a continuous tracing.
In the first report from this laboratory 3 it
was concluded that the continuous flow
AutoAnalyzer system had the serologic
capabilities to perform all routine blood
typing procedures, and from the D u reactions it was evident that it had the sensitivity to go much further. It was also mentioned that application to a routine operation would have to await the development
of a multichannel machine which could reReceived, November 14, 1964.
* Technicon I n s t r u m e n t s Corporation,
cey, New York.
Chaun-
cord simultaneously the results of several
tests from a single sample of blood.
In a subsequent report4 a detailed description was given of the mechanical and
serologic modifications involved in the development of a prototype 8-channel machine for routine use. The most critical
problem this machine solved was that of
obtaining a simultaneous recording of the
tests from each sample of blood in order that
10 to 20 samples receiving 80 to 160 tests
could be in the system at the same time;
that is, to insure that the 8 sets of tests
from a single sample were in phase at the
end of their transit through the system.
This was accomplished by changing from a
capillary to a large bore manifold. The consequent reduction in pressure within the
system permitted relatively uniform flow
rates in all 8 channels. In addition, to reduce
the machine's complexity and number of
components, a special 200-place sampler
was constructed, a single compound colorimeter and a 4-pen recorder were incorporated, and a programmer was devised to
coordinate the sampling, sensing, and recording sequences.
A diagrammatic representation of the 8channel system is shown in Figure 1. The
dual probe aspirates plasma and cells from
the sample which has been taken into anticoagulant and separated by centrifugation.
Each stream is then subdivided into 4; 3 are
tested with reagents and 1 serves as a control
or blank. A programmer takes the outputs
from the 4 plasma circuit cuvets of the
multichannel colorimeter and translates
these to the 4-pen recorder for 1 min.; then,
during the second minute, it does the same
for the cell typing circuits. The programmer
also coordinates the 2-min. sampling and
wash cycles so that the samples arrive at the
colorimeter at the precise time the output of
the colorimeter is being sensed by the recorder. The prototype machine also incorporates a special sampling system de-
454
May 1965
455
BLOOD TYPING WITH AUTOANALYZER
FLOW DIAGRAM OF 8 CHANNEL SYSTEM
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COLORIMETER
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DIRECT TYPING
(ON CELLS)
(2 SETS OF 4 CIRCUITS AS SHOWN ABOVE)
F I G . 1. Schematic drawing of AutoAnalyzer hemagglutination system for routine blood typing
signed to reduce the problem of plugging
attendant with the use of whole blood
samples.
Details of sampling, backwashing, and
cell dilution are illustrated in Figure 2.
During the first minute both solenoid valves
are positioned as shown in the plasma circuit;
that is, the sample is aspirated directly into
the subdivided portion of the circuit and the
wash-saline is being returned to the reservoir. At the end of the first minute the probe
lifts from the sample tube, swings to the side
of the sampler, and drops into the wash
" U " tube {inset), and both solenoid valves
shift to the position shown for the cell
typing circuit. In this position the washsaline is directed into the sample line through
a " T " fitting for the second minute. The
direction of flow is thus reversed from the
" T " to the tip of the probe. This latter
mechanism serves to dislodge plugs and increases the efficiency of separation of the
sample. During the wash phase the sample
tray brings the next sample into position
for sampling, and the cycle is repeated.
In the cell dilution circuit the packed
cells are joined by a large stream of 0.1 per
cent bromelin in saline solution which has
been segmented with air. This is mixed, and
a small portion of the dilute stream is resampled for subdivision into the 4-cell typing circuits. Immediately prior to this, a
major proportion of the whole is pumped out
through a debris removal " T " to eliminate
particulate matter, thus contributing further
toward elimination of the plugging problem.
Air bubbles are also removed prior to resampling.
With the incorporation of the above
mechanical modifications to overcome problems of phasing and plugging, the first production model of a compound machine was
used in a comparative study of machine
with manual results. This was done in col-
456
STURGEON AND McQXJISTON
Vol. 48
SAMPLER
TO PLASMA CIRCUITS
DEBUBBLING
(TO WASTE)
•*
TO CELL CIRCUITS
DEBRIS REMOVAL
PLASMA CIRCUIT
BLOOD CIRCUIT
WASH CYCLE
F I G . 2. Sampling, baokvvashing, and cell dilution circuits. T h e inset illustrates the position of the
sample probe in the wash " U " tube. T h e solenoid valves are in the sample position for t h e plasma circuit
and the wash position for the cell circuit.
laboration with the Laboratory of the
Regional Blood Center for the Los Angeles
and Orange Counties Chapter of The
American National Red Cross. It is the
purpose of this paper to report the findings
of this study.
MATERIALS AND PROCEDURE
Commercial anti-A and anti-B sera without the dye but otherwise meeting N I H
specifications were used, diluted to 1:4 with
saline solution. The anti-D reagent was
prepared by diluting raw serum obtained
from a type AB donor to 1:32 with saline
solution and 10 per cent acacia to a 1.7 per
cent gum acacia concentration. The raw
serum had a titer, as determined by the
indirect antiglobulin technic, of 1:512. For
plasma typing, reagent cells of type A1; B,
and 0 , Rh-positive, were prepared in a 4 to
6 per cent concentration in saline solution
containing 1 Gm. of bromelin per liter. The
latter was also used as diluent for the packed
LEGEND
cells in the cell typing circuit. Saline solution was prepared by dissolving 9.0 Gm. of
NaCl in a liter of distilled water. To each
liter of saline solution 2 drops of Tween-20
were added. The activity of the bromelin
solution deteriorated rapidly; hence it was
freshly prepared every day. A stock gum
acacia solution was prepared by dissolving
10 Gm. of reagent gum and 1 Gm. of
Na 2 HP0 4 in 100 ml. of distilled water. It
was found that the enhancement of the D
reactions, and particularly D", by gum
acacia diminished greatly when the stock
preparations had been stored in the refrigerator for more than 3 to 4 months.
The unknown blood samples were collected into specially prepared evacuated
pilot tubes which contained 3 ml. of sterile
ACD solution as anticoagulant.f A liquid
anticoagulant in relatively large volume was
found to be the most effective in preventing
f Bee ton, Dickinson and Company,
ford, New Jersey.
Ruther-
May 1965
BLOOD TYPING WITH AUTOANALYZER
clotting of the sample. Seven milliliters of
blood were taken into the pilot tubes by
nurses during routine blood collection at the
Center; no special precautions were taken
to mix the blood and anticoagulant. The
tubes were labeled with the donor's blood
number and stored in a refrigerator.
Twelve to 24 hr. later the samples were
centrifuged and loaded into the sample tray.
The sample numbers were then copied in
sequence onto a standard form; opposite the
sample number the machine results of each
test were later recorded, and from these the
interpretation of final blood type was indicated. In a column parallel to the latter, the
manual results were transcribed and a final
comparison was made.
Comment on Procedures
Usually, the samples were tested within
24 hr. of the time of their collection. On occasions, when the tests were delayed for more
than 3 days, a significant incidence of plugging of the cell sample probe occurred, resulting in a "no sample tracing" for that
particular sample. The backwash system
served to dislodge the great majority of such
plugs; hence only 1 sample was lost. It was
also found that forceful centrifugation frequently resulted in plugging of the cell
sample probe. On the other hand, sedimentation of the sample held overnight in the refrigerator often resulted in inadequate
packing, leaving the cell layer above the tip
of the plasma probe. A solution to both
problems is provided by centrifuging the
samples for 10 min. at 906 X g (2250 r.p.m.;
radius to tip, 16 cm.).
As the number of specimens tested serially
approximated 50, the need for a routine
cleansing schedule of the machine became
apparent. The adherence of agglutinates to
the glass and plastic tubing of the manifolds
was a source of considerable trouble, particularly in the anti-D circuit. The adsorbed
agglutinates attain large size, break off, and
obstruct the decanters; then phasing is upset,
sensitivity is diminished, and the cuvets are
clogged. In order to overcome this, after
every 50th specimen, the sampling sequence
is interrupted by a series of 4 tubes containing cleansing solutions. The first contains
457
saline solution, the second a 30 per cent
solution of saponin, and finally 2 saline
specimens to wash out the saponin.
As the number of specimens tested without
interruption reaches 200 or more, there is a
tendency for a fine white precipitate to adsorb to the glass surfaces; this clouding is
particularly troublesome to the flow cells. A
gradual rise of the optical density setting of
the reagent bases to as much as 1.0 may
occur in the course of a day; the amplitude
of weak reactions becomes too small to be
detected. Therefore, after every 200 specimens of blood, a solution of N/10 sodium
hydroxide and 5 per cent urea has to be
introduced through all of the reagent lines,
as well as the water addition lines. The
return of all tracings to "saline base," that
is, an optical density of zero, indicates that
this phase of cleansing is adequate. A minimal period of 40 min. is required for the
operation. First, distilled water should be
run for 10 min. to clean out any substances
which may be denatured by the cleaning
solution. This is followed by 20 min. of
cleaning solution and another 10 min. of
saline solution to remove the last traces of
the cleaning solution.
Finally, each day in preparation for the
operation of the machine, steps should be
taken to insure that the results of all 8 tests
on each sample are being recorded simultaneously; that is, the "phasing" should be
adjusted. Although this is a difficult operation whenever pump tubings are replaced
and will not be described here, fine adjustments can be made by consulting the tracings from the preceding run. The removal or
addition of a few centimeters of the plastic
tubing in the phasing coils accomplishes this
end.
During the course of operation the various
components of the blood typing machine
require periodic inspection. In the sampler
the alignment of the sample probe with the
sample and rinse tubes, the position or
depth of the 2 probes relative to red cell and
plasma, and the satisfactory functioning of
the backwash system must be monitored. In
the cell dilution stage occasional inspection
of the bubble pattern, of the pump tubing
for tortuousness, and of the bubble removal
458
Vol. 43
STURGEON AND McQUISTON
TABLE 1
AUTOANALYZER BLOOD T Y P I N G
MACHINE;
ABBREVIATED MONITORING L I S T
I. Sampler
A. Probe alignment, samples and rinse
B . Probe depth, cells, plasma
C. Backwash, discharge during wash
I I . Cell dilution circuit
A. Enzyme solution
B. P u m p tubings
C. Bubble p a t t e r n
D . Obstruction
I I I . Cell and plasma circuits
A. P u m p tubings
B . Bubble p a t t e r n s
C. Reagents; a d e q u a t e ; lines in place;
mixing and flow
D . Agglutinates, none escaping decanter
IV. Miscellaneous pumps
A. Decanters
B . Colorimeters
C. Water addition
D . Saline addition
V. Recorder
A. P e n s : ink supply, lifting, torque
B . P a p e r : supply, movement, and alignment
C. Phasing
system to determine that air is not being
drawn into the dilute cell suspension sample
lines is required. Similar observations are
necessary for like components of the cell and
plasma typing manifolds. In addition, the
supply of reagents must be kept adequate,
the reagents cell beakers must be immersed
in ice water, and proper mixing of these cell
suspensions must be maintained.
The recorder should be checked periodically, and adjustments in the programming
should be made if both plasma and cell
typing results are not being recorded at the
critical part of their curves. The mechanisms
of the recorder require inspection; adequacy
of the supply of ink and paper should be
noted; electrical adjustments are necessary
if the pens are over- or undersensitive. The
need for minor positioning of the pens relative to the surface of the paper is indicated
by failure of the pens to write at certain
portions of the tracings, or their writing at a
time when they are supposed to be lifted
off of the paper. A monitoring list has been
prepared to insure regular inspection of all of
these facets of the machine. Table 1 is an abbreviated sample of such a list.
When the testing of all the samples in a
tray (maximum 200, less positions used for
saponin-saline washing) has been completed,
the record is removed, and the results for
each sample are numbered by beginning with
the first set of 8 tracings, according to the
sequence of samples in the tray. The pattern
of the saline-saponin wash sequence is distinctive and fixes the position of the 49th
through 52nd specimens. The results from
the plasma typing are recorded in appropriate columns of the interpretation form,
and the plasma type is set down. Those of
the cell typing circuits are handled similarly,
and the final ABO and Rh types are recorded. In the event of an inconsistency between the final machine and the manual
results, or an uninterpretable record, appropriate signs are made and, if indicated,
the sample is held out for retesting or further
evaluation.
RESULTS
Comparative studies were made with the
8-channel prototype machine based on the
standard cell typing manifold illustrated in
Figure 3 and on the procedures indicated
above. In the course of running several
thousand tests it became apparent that the
results of machine cell typing, for the most
part, agreed with the manual tests. It also
was evident, although the plasma typing
circuits had sufficient sensitivity to detect
a- and /3-antibody, that there was a high
proportion of false-positive reactions. This
necessitated the redesign of the manifold
for plasma typing in order to stabilize the
tracings made by negative plasma samples.
Comparison of the plasma typing circuit
with the cell typing circuit in Figure 3 illustrates the changes. The mixing coil, after
the addition of saline solution, was brought
into close proximity to the first decanter.
This served to resuspend cells immediately
prior to decantation and thus overcome the
nonspecific plasma sedimentation, and yet
allow sufficient specific sedimentation of agglutinates to detect weak reactions. Elimination of the settling coil and the substitution
of a mixing coil similarly positioned between
the first and second decanters contributed
May 1965
459
BLOOD TYPING WITH AUTOANALYZER
C E L L T Y P I N G CIRCUIT
MIXINOCC*.
PHASING C O L 2ND DECANT
SETTLINGCOCL
1ST OECANT
PULSE CHAMBER f
WATER TO HEMOLYZE CELLS
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MIX1NGCOIL
REACTION COt.
MIXING C O L
" PlA.SE CHAMBER
AGGLUTINATED CELLS TO WASTE
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SALTSOUmON
AIR
REAGENTS i
PLASMA TYPING C R C U I T
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F I G . 3. Hemagglutinating mnnifolcls for routine blood typing. Modifications for plasma typing include elimination of settling coil, substitution of mixing coil, and repositioning of mixing coils in close
proximity to decanters.
to the same objective. In addition to the
importance of proximity of the coils to the
decanters, the whole system is highly sensitive to their positioning in various planes.
In addition to the nonspecific (falsepositive) effects with plasma typing, the
formation of excessively large agglutinates
in cell as well as plasma circuits continued
to cause many of the troubles, as mentioned
previously. These difficulties were overcome
by modifications which retarded the rate of
flow through the decanters and increased the
diameter of the aspirating portion, thus
enabling them to handle even the largest cell
masses. This type of decanter is shown in
Figure 3.
With the modified plasma circuits and
decanters comparative studies once again
were made with the prototype machine. In
light of the knowledge gained with these
earlier experiences a system for classification
of AutoAnalyzer blood typing results into 5
categories relative to manual results was
evolved. These are listed in Table 2. In the
first category there is complete agreement
between manual and automatic results. In
the second there is also complete agreement
between manual and automatic results, but
additional serologic information is computed
by the machine. For instance, an irregular
antibody or a weak variant such as an A2B,
TABLE 2
CLASSIFICATION OF AUTOANALYZER
BLOOD T Y P I N G
RESULTS
I. Automatic and manual results equivalent
I I . Automatic results give additional serologic
information
A. Irregular antibody
B. A 2 B, A3B
C. D "
D . Other
I I I . Automatic results internally inconsistent
A. False-positive or false-negative plasma
or cell typing result
B . Results requiring subjective interpretation, usually due to minor mechanical
problems, faulty adjustments, etc.
IV. Gross technical failure
A. Routine operating procedures not followed
B . Major mechanical or electrical failure,
breakdown of AutoAnalyzer component
V. Automatic and manual results in total
disagreement
A. Automatic results in error
B. Manual results in error
A 3 B, or perhaps a type D u , may be found.
The third category includes all internally
inconsistent results, that is, those in which
machine plasma and cell typing results do
not confirm each other. It also includes those
460
Vol. 48
STURGEON AND McQTJISTON
AUTOMATIC BLOOD TYPING:
RECORD, INTERPRETATION AND CLASSIFICATION SHEET
Blood
C o l l e c t i„o „n
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FIG. 4. Form used in the interpretation of machine results, the comparison of manual results, and
classification of accuracy. The examples given are hypothetical results illustrating the 5 classification
categories.
results which require a special understanding
of some of the deficiencies of the AutoAnalyzer to be interpreted correctly. Of
particular importance in this connection is
an appreciation of carry-over from a strongpositive plasma to a following negative
plasma. In addition, the slight disrupting
action of the saponin wash on immediately
preceding and following samples must be
understood.
In the fourth category are included missed
records, as the result of mechanical failure
or lapses in operating procedure. For example, most of the data were collected by
allowing the machine to run unattended for
several hours after the end of the working
day. On occasions, the supply of record paper
or reagents was inadequate or occlusions
developed in reagent or sample lines that
could have been detected had there been a
person monitoring the machine. Included in
this category would be failures resulting
from placing an inadequate specimen in the
sample tray; it also includes interpretive
errors, that is, failure to read and interpret
the tracings correctly.
The fifth category (Table 2) is that in
which the manual results do not confirm the
final decision based on the machine results;
that is, instances in which the machine results lead to an erroneous blood typing
without giving any suggestion of an inconsistency. An example of the form used to
insure a systematic collection of the data
from the machine results is illustrated in
Figure 4. The form includes a column for
transcription of the manual results and a
final column for classification of the machine
results according to the above 5 categories.
This form of analysis has been applied to
May 1965
461
BLOOD T Y P I N G W I T H A U T O A N A L Y Z E R
TABLE 3
ANALYSIS OF AUTOANALYZER BLOOD T Y P I N G
Day
Classification
No. of
Samples
I
1
2
3
4
5
102
185
180
184
200
RESULTS
92
183
177
180
189
(57%)
(99%)
(95%)
(98%)
(95%)
II
2
2
2
1
6
(1%)
(1%)
(1%)
(0.5%)
(3%)
the results from each full sample tray of
bloods tested daily over a recent 1-week
period (Table 3). The combined categories
I and II include from 58 to 100 per cent
of the results; that is, they were in complete
agreement with the manual results. The 1
to 3 per cent of the results in category II
include 4 instances of irregular antibodies,
7 examples of A2B or A 3 B, and 2 Rh 0 variants. There were 13 samples which gave
category III results. Six of these were falsenegative plasma reactions resulting from
lack of sensitivity; however, on retesting in
the machine, 2 had positive results. One of
the 13 in category III was a weak A3B that
yielded a negative anti-A reaction. The
remainder in category III were the results
of minor mechanical difficulties. On the first
day there was a major mechanical failure,
hence the 42 per cent of results in category
IV on that day; this was caused by occlusion
of a reagent cell line. The 2 results in category V represent blood specimens which
gave peculiar but nevertheless distinctly
positive tracings. They were found manually
to be Rh-negative; this was confirmed by
further tests, including tests for D" by antiglobulin and elution technics. The 2 blood
specimens were subsequently retested in the
machine and yielded typical Rh-negative
tracings; for the present the reasons for this
erratic behavior remain inexplicable. This
is the only time in the testing of several
thousand bloods that there has been such an
occurrence.
Assuming the type of difficulty encountered in the run of the first day (Table
3) can be overcome, the average of the last
4 days may be taken as indicative of the accuracy of the existing machine. Strictly
III
IV
V
OS (42%)
5 (3%)
3 (1.5%)
5 (2%)
2 (1%)
objective readings give complete agreement
with manual results in 97 per cent of the
tests. For the most part, the remaining 3
per cent can be correctly interpreted subjectively; or, in doubtful cases, the correct
result is obtained on rerunning the sample
through the machine or by supplemental
manual tests. Should there be any further
false-positive or false-negative Rh typing
results (category V), as observed on day 3
above, allowance will have to be made for a
duplicate Rh testing circuit.
DISCUSSION
At present the automation of routine blood
typing procedures based on the continuous
flow principle has reached an advanced stage
of development, albeit not perfected. There
seems to be little doubt (1) that adequate
sensitivity for cell and plasma typing without significant number of false-positive
signals from negative plasma or cell samples
has been developed, (2) that the problems
resulting from overgrowth of agglutinate size
have been overcome, and (3) that routine
procedures have been defined for relatively
large volume operations. From our most
recent experience there remain, however,
3 major sources of difficulty; namely, plugging, phasing, and cleansing.
Throughout the developmental stages the
serious consequences of plugging, particularly by small clots in the cell sample lines,
were recognized. The debris removal device
was installed and, on suggestion to the manufacturer, the solenoid-activated valve system for backwashing was developed. This
prevented single plugs from obstructing
subsequent samples. In addition, a standard
sample collection and preparation procedure
462
STURGEON AND McQUISTON
based on the use of a relatively large volume
of liquid as anticoagulant, centrifugation
at a specific relative centrifugal force to
separate the cells from the plasma, and the
testing of samples within 1 to 3 days of collection has to all intents and purposes
eliminated plugging at the sample probe.
The solution to the remaining problem of
plugging of reagent lines should be relatively simple. A device in the reagent lines
for preliminary filtration or by modification
of reagent line diameters could overcome this
problem.
At present the 8 circuits remain in relatively good phase for periods of hours but,
with continuous use, adjustments are required at least daily, during which time
operation must be interrupted. These are
time consuming, require the attention of 2
people, and can be quite frustrating. It
would be greatly simplified if, rather than
having to remove segments of the phasing
coils, the procedure could be performed
while the machine is in operation. A system
of bypasses that could be opened or closed
as circumstances dictate should make this
possible; this would permit minor adjustments to be made while unknown samples
are being tested.
The present system necessitates cleansing
after every 50th sample to dislodge agglutinates adsorbed to the glass and the
plastic tubing of joints. The use of saponin
preceded and followed by saline solution
was evolved empirically; it introduces complications. First, the 4 sample positions lost
to the cleansing tubes represent an 8 per
cent loss in over-all sampling rate. The
viscosity or flow characteristics of the
saponin are such that flow rate disturbances
are created which upset phasing for preceding and trailing samples. This has led
to occasional misinterpretations. The reactivity of the anti-D circuit is also impaired
in the first specimen after the last saline
wash. The elimination of agglutinate adsorption, perhaps through modification of
the glass or plastic surfaces or of the suspension medium for cells and antiserum,
would constitute a valuable contribution
toward perfecting the entire device.
The cleansing after each 200 samples is
dictated primarily because of clouding of
Vol. 43
the flow cells by a fine white precipitate.
Under present circumstances this cleansing
also can be done only when the machine is
not in operation; it consumes about 1 hr. of
operation and technician time. Cleansing
could be done automatically through the
incorporation of an ancillary reservoir of
cleaning solution and a pumping system
that would introduce the solution through
" T ' s " into the saline and water addition
lines; it could be activated automatically
at the end of each sample tray of 200 specimens.
In addition to the major problems, a few
minor mechanical difficulties need to be
overcome in order to gain the maximal
efficiency from the present device. Not all of
the recorder pens clear the paper in the
shifting phase toward the end of the 200sample series. A more efficient system is
needed for centrifuging the samples and for
loading them in the tray. Interpretation of
results could be expedited if the record paper
were folded rather than rolled up. A mechanical cooling and improved mixingsystem for the reagent cells and other reagents would save technician time and give
greater reliability and reproducibility to the
plasma typing results, especially if the machine is to be operated unattended for
several hours at a time.
Of the total technician time devoted to
operating the present machine, a majority
is required to cope with the above problems.
Time is also needed for the tabulation of
sample numbers on the interpretation sheets.
In addition, the reading, recording, and
interpretation of results consume X% hr.
Thus, the 8-hr. working day is spent in
preparation for a run of 200 samples (less
14 lost to cleansing) and the interpretation
of the previous day's output. The machine
is then allowed to operate unattended during
the night. For this amount of production,
\Yi technician days are required. If the
existing deficiencies of the present machine
were corrected, and 2 technicians were to
stagger their work days, it should be possible to make 2 runs of 200 (400 specimens
of blood) per 24 hr.
Much greater efficiency should be possible
in the future with the incorporation of electronic devices to give a printed interpreta-
May 1965
BLOOD T Y P I N G W I T H
tion of the results and to sense the number
of the pilot tube and apply it to the interpretation. It would seem, with such future
developments, that the productivity of the
system should be in the order of 400 specimens of blood tested with properly identified
labels printed per technician per day with a
maximum of 600 tests per machine per 24 hr.
It is also possible that the sampling rate
could be increased from 30 per hr. to 40 per
hr. with a gross output then of 800 samples
per machine clay.
SUMMARY AND
CONCLUSIONS
This has been a report on progress in development of a fully automated system,
based on the continuous flow principle and
decantation of agglutinates, for the routine
typing of blood. A description has been given
of a backwash system to overcome plugging
of the sample lines and modifications of the
manifold which facilitate the maintenance
in phase of the set of 8 tests from each
sample of whole blood.
Upon performing the serial testing of the
large numbers of specimens of blood, as
would be done in a routine blood bank setting, numerous additional problems have
been encountered. There was a tendency for
agglutinates to adhere to the glass and
plastic tubing and to break off after reaching
unusual size, with subsequent occlusion of
decanters and occlusion of the light path
through the flow cells. Enlargement of the
bore of the decanters effectively solved this
problem. The problem of frequent falsepositive signals from negative plasma
samples having enhanced sedimentation
characteristics was solved by repositioning
a mixing coil and by substituting a mixing
coil for the sedimentation coil between
decaliters.
In spite of these modifications, continuous
ATJTOANALYZER
463
faultless operation of the device has not been
achieved because of plugging in reagent
lines, changes in phase over several hours'
use, and the necessity for frequent cleansing
of manifolds and flow cells. Solution to these
problems appears quite possible, and, with
the incorporation of automatic interpretation and labeling systems, the productivity
of the system should be in the order of 400
to 600 specimens of blood tested for a, j3,
irregular antibodies, A, B, and D per technician per day.
The ultimate definition of accuracy of
blood testing by the continuous flow principle, therefore, awaits further experience
based on the careful collection of a large
body of data. This should be done in a manner that allows interpretation of the serologic as well as the mechanical performance
of the machine. Pending such information,
the prospects seem to be good for the complete automation of large-scale routine
blood typing procedures.
Acknowledgments.
Miss Lucile S. Freeman,
Chief Nurse of the Los Angeles-Orange Counties
Blood Center, and her stall provided the great
numbers of specimens which made this s t u d y
possible. Mr. Nick II. Maverakis provided technical assistance.
REFERENCES
1. Allen, F . H., Jr., Rosenfielcl, R. E., and Adebahr, M. E . : Kidd and Duffy blood typing
without Coombs serum. Adaptation of t h e
Auto-Analyzer hemagglutination
system.
Vox Sang., 8: 698-706, 1963.
2. McNeil, C , Helmick, W. M., and Ferrari, A.:
A preliminary investigation into automatic
blood grouping. Vox Sang., 8: 235-241, 1903.
3. Sturgeon, P . , Cedergren, B., and McQuiston,
D . : Automation of routine blood typing procedures. Vox Sang., 8: 43S-451, 1963.
4. Sturgeon, P . : Un systcme completement a u t o matism pour elTectuer simultanement tous les
tests de routine pour ^identification des
groupes sanguins. Transfusion, Paris, accepted for publication.