Unit Placement Errors: A Potential Risk Factor for ABO and Rh

Unit Placement Errors: A
Potential Risk Factor for ABO
and Rh Incompatible Blood
Transfusions
Policy at our institution requires the
hospital whole blood and packed RBC
inventory (approximately 400 units)
to be stored in an orderly arrangement
without crowding, with units of the
same ABO/Rh grouped together and
each group of units clearly segregated
from the others. In spite of this policy,
over a 38-month period, 112 of 96,581
units (0.12%) were placed into the inventory incorrectly (so called unit
placement errors). Thirty-seven of
these unit placement errors (0.04%)
could have resulted in ABO incompatible crossmatches or transfusions,
and an additional 20 errors (0.02%)
could have resulted in Rh incompatible transfusions. These data demonstrated the need for our laboratory
personnel to routinely perform a systematic check of the blood inventory
to detect incorrectly located units and
to carefully check the group and type
From the Los Angeles County+University of
Southern California Medical Center, Los Angeles, Calif.
Reprint requests to the Los Angeles County*
University of Southern California Medical Center, 1200 N State St, PO Box 771, Los Angeles,
CA 90033 (Dr Shulman).
194
Laboratory Medicine
on each unit at the time of its selection.
Although these data were collected at
a large and busy transfusion service
laboratory, they may be representative
of what occurs at small as well as at
other large facilities. It might be prudent for hospital transfusion services
to have a policy that both minimizes
the occurrence of unit placement errors
and allows for their routine detection,
should they occur.
O
ne of the most feared complications of blood component therapy is an ABO incompatible
transfusion. In one large study, approximately 1 in every 17,000 transfusions
resulted in an ABO incompatible transfusion reaction.1 While most (approximately 90%) ABO incompatible transfusions are not fatal,2 it has recently
been estimated that approximately one
in every 100,000 transfusions results
in a fatal hemolytic transfusion reaction, most of which are caused by
ABO incompatible transfusions.3
Currently, the Food and Drug Administration (FDA) requires that all fatal
transfusion reactions be reported to
the Director, Office of Compliance,
Vol. 22, No. 3 March 1991
Center for Drugs and Biologies as soon
as possible by telephone or telegram,
and in writing within 7 days after the
fatality.4 A recent review of fatal transfusion reactions reported to the FDA
between 1976 and 1985 revealed 158
deaths from acute hemolysis, of which
131 (83%) were ABO transfusion errors.5 In most instances, the fatal ABO
incompatible transfusions involved the
transfusion of group A packed cells to
group O recipients. While the majority
of these ABO transfusion fatalities involved nurses and/or physicians, several errors were made by laboratory personnel, including errors in serologic
testing (20), confusing samples or records (16), and/or releasing the wrong
units for transfusion (9).
Although none of the fatal transfusion errors reported to the FDA between 1976 and 1985 followed an Rh
incompatible transfusion,5 these transfusion errors carry the risk of alloimmunization and hemolytic transfusion
reaction and can predispose to hemolytic disease of the newborn.6,7
At our institution, a large county
facility servicing the metropolitan Los
Angeles area, we have observed several reasons why laboratory workers
inadvertently select ABO or Rh incompatible blood for patients. For exam-
Downloaded from http://labmed.oxfordjournals.org/ by guest on October 13, 2016
Ira A. Shulman, MD, and Donald Kent, MTASCP
B
ackground and Description of
Source of Error
As recommended by the American
Association of Blood Bank's Committee on Inspection and Accreditation,
the policy at our institution requires
the hospital whole blood and packed
RBC inventory (approximately 400
units) to be stored in an orderly arrangement without crowding,' with
units of the same ABO/Rh grouped together, and each group of units clearly
segregated from the others. Prior to
1987, the blood inventory was checked
once daily for incorrectly located units
(eg, group A units placed with group
O units). In spite of this policy, we experienced an ABO incompatible crossmatch in 1986 because a technologist
selected a group A/Rh-positive unit
that had been placed among the group
O/Rh-positive blood units. Although
the technologist failed to notice initially that the unit was labeled as A/Rh
positive, the immediate-spin major
crossmatch test was incompatible,
alerting the technologist to the ABO
incompatibility. The blood was not
transfused to the patient.
The aforementioned blood selection
error was of concern for several reasons. First, the ABO incompatible unit
of blood might have been issued. Although the crossmatch was incompatible in this case, the major crossmatch
does not always show agglutination
15
10
5
l
l
ill
lU lll-.ll i.lll. i. .. Ill1 .1
J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F
1987
1988
1989
90
Unit placement errors January 1, 1987, to February 28, 1990.
and/or hemolysis when ABO incompatibility is present.10-15 Second,
an immediate-spin crossmatch is not
performed on all units at our institution prior to issue. Uncrossmatched
units are released when blood is needed in critical situations when the clinician is unwilling to wait for an immediate-spin test to be performed.16 If an
ABO incompatible blood selection
error occurred in such an emergent
circumstance, the blood could be
issued and transfused without detecting the incompatibility. Furthermore,
we found by surveying some of our
technologists that inventory errors of
this kind were not considered to be
rare occurrences, although objective
data were unavailable to us in 1986 to
quantify the problem.
These observations suggested to us
that if experienced technologists could
inadvertently select ABO incompatible
units for potential transfusion recipients, and if a major crossmatch might
be either falsely negative or not done
at all, sooner or later an ABO incompatible transfusion would occur. Thus,
we thought a corrective action plan
was necessary.
C
orrective Action Plan
To reduce the likelihood that
another incorrectly located unit
might potentially jeopardize a patient's
care, we instructed our technical staff
to check the blood inventory at the beginning of each shift for units that might
be in the wrong location. Each incorrectly located unit was to be placed in
its correct location, and each so called
unit placement error was to be documented so that the magnitude of the
problem could be determined.
R
esults
From January 1, 1987, to March
1, 1990, 73,835 units of red cell
components were received from blood
collection centers and placed into the
hospital blood inventory. An additional 22,746 units of blood were removed
from the inventory, crossmatched but
not transfused, and then placed back
into the inventory. Thus, the total number of units placed into the inventory
was 96,581. These units were placed
into the inventory by the night shift
(38%), day shift (46%), and evening
shift (16%); 112 units were discovered
to have been placed in the wrong inventory location (0.12%). Forty-one
(37%) of these units were discovered
by the night shift, 35 (31%) were discovered by the day shift, and 36 (32%)
were discovered by the evening shift.
The number of unit placement errors found per month during the study
are shown in the Figure. During 9 of
38 months there were no errors discovered. However, in 1 month 12
errors occurred. A workload productivity analysis failed to show any obvious explanation why more unit placement errors occurred in some months
compared with others.
Of the 112 units discovered in the
wrong inventory locations, 37 (0.04%)
might have resulted in ABO incompatible crossmatches or even ABO incompatible transfusions, and 20 units
(0.02%) might have resulted in Rh incompatible transfusions. Since most
Laboratory Medicine Vol. 22, No. 3 March 1991
195
Downloaded from http://labmed.oxfordjournals.org/ by guest on October 13, 2016
pie, technologists have selected blood
for one patient when it was actually
intended for another patient with an
identical or similar-sounding name.
ABO or Rh incompatible blood has
been selected for transfusion following
technical or clerical errors in ABO or
Rh testing.8 Errors like these may result
from insufficient time or attention devoted to required tasks, from human
fatigue, from excessive workload, from
failure to follow established procedures, and/or from inadequate training. Fortunately, these kinds of errors
are sporadic and do not commonly
occur. However, we recently discovered a relatively common error that
has the potential to place some
patients at risk for receiving ABO
and/or Rh incompatible blood. This
article describes that source of error
and our attempts to eliminate it.
Unit Placement Errors Discovered
During a 38-Month Study That
Potentially Set Up ABO Incompatible Crossmatches and/or Transfusions
No. and Blood Group
of Incorrectly Located
Units
Kind of Unit Placement Error*
19, group A
6, group B
1, group AB
Unit put with
group 0 units
2, group B
1, group AB
Unit put with
group A units
3, group A
5, group AB
Unit put with
group B units
Rh-negative individuals do not have
anti-D, errors in which Rh-positive
blood is selected for Rh-negative recipients would not be detected by the
major crossmatch. One of the misplaced units could have caused both
an ABO and Rh incompatible transfusion since the unit was group AB/Rh
positive and was placed with the group
B/Rh-negative units. The Table contains the various combinations of ABO
incompatibility that were potentially
set up by unit placement errors.
Fortunately, all of the 112 misplaced
units were discovered to be misplaced
before they were transfused. Although
no ABO incompatible transfusions
occurred as a result of laboratory error,
unfortunately, misidentification of patients and/or their specimens at the
time of phlebotomy and errors in patient identification at the time transfusions were started did result in some
nonfatal ABO incompatible transfusions.
r
omment
In the current study, one of
every 862 units was incorrectly
placed into the blood inventory. Although each technologist is aware of
the importance of placing units in the
correct inventory locations, one in
196
Laboratory Medicine
Vol. 22, No. 3 March 1991
the risk that an ABO or Rh incompatible unit will be issued by our blood
bank. Other busy blood bank laboratories may wish to modify their existing policies (or create new policies) if
their data are similar to oursQ
References
1. Mayer K: A different view of transfusion safety-type and screen, transfusion of Coombs incompatible cells, fatal transfusion-induced graft vs
host disease, in Polesky HF, Walker RH (eds):
Safety in Transfusion Practices. College of American Pathologists, Skokie, 111, 1982.
2. Barton JC: Noninfectious transfusion reactions, in Dutcher JP (ed): Modern Transfusion
Therapy, vol 1. Boca Raton, Fla, CRC Press,
1990.
3. Office of Medical Application of Research,
National Institutes of Health: Perioperative red
cell transfusion. JAMA 1988;260:2700-2703.
4. Title 21 Code of Federal Regulations 606.170,
June 1990.
5. Sazama K: 355 reports of transfusion-associated fatalities: 1976-1985. Transfusion
1990;30:583-590.
6. Mollison PL, Engelfriet CP, Contreras M:
Blood Transfusion in Clinical Medicine, Eighth
Edition. Boston, Mass, Blackwell Scientific Publications, 1987.
7. Petz LD, Swisher SN (eds): Clinical Practice
of Transfusion Medicine. Churchill Livingstone,
New York, 1989.
8. Meyer EA, Shulman IA: The sensitivity and
specificity of the immediate spin crossmatch.
Transfusion 1989;29:99-102.
9. Rosvoll RV (ed): Accreditation Requirements
Manual, ed 3. Arlington, Va, American Association of Blood Banks, 1990.
10. Berry-Dortch S, Woodside CH, Boral LI:
Limitations of the immediate spin crossmatch
when used for detecting ABO incompatibility.
Transfusion 1985;25:176-178.
11. Judd WJ, Steiner EA, O'Donnell DB, et al:
Discrepancies in reverse ABO typing due to prozone: How safe is the immediate-spin crossmatch? Transfusion 1988;28:334-338.
12. Lamberson RD, Boral LI, Berry-Dortch S:
Limitations of the crossmatch for detection of
incompatibility between A2 red blood cells and B
patient sera. Am J Clin Pathol 1986;86:511513.
13. Mintz PD, Anderson G: Limitation of polybrene to detect ABO incompatibility. Vox Sang
1986;51:318-320.
14. Shulman IA, Meyer EA, Lam H-T, et al:
Additional limitations of the immediate spin
crossmatch to detect ABO incompatibility. Am J
Clin Pathol 1987;87:667.
15. Shulman IA, Nelson JM, Lam H-T, et al:
Unreliability of the immediate spin crossmatch
to detect ABO incompatibility. Transfusion
1986;25:588.
16. Shulman IA, Morales J, Nelson JM, et al:
Emergency transfusion protocols. Lab Med
1989;20:166-168.
Downloaded from http://labmed.oxfordjournals.org/ by guest on October 13, 2016
"Error rate-ABO incompatible unit placement ••
37/96,581=0.04%.
every 2,610 units was placed in a location that could have contributed to an
ABO incompatible transfusion, and 1
in every 4,829 were misplaced for Rh
incompatibility. The present policy of
checking the blood inventory three
times daily, adopted to minimize the
likelihood of selecting a misplaced
unit for a patient's transfusion, showed
the importance of routinely performing a systematic check of the blood
inventory for incorrectly located units
that may have remained undetected
for more than 8 hours (one work shift).
In fact, if a check were done only once
daily, (as was our previous policy),
37% might not have been discovered
for up to 16 hours, and 32% of the
incorrectly placed units might not have
been discovered for up to 24 hours.
Shortening the time interval between
the placement error and its detection
reduces the risk of inadvertently selecting a unit of the wrong ABO/Rh.
Although we were unable to totally
prevent unit placement errors, other
institutions might be more successful
using other problem-solving approaches. For instance, at our institution, over
80% of inventory units are shipped to
us from a regional center and are labeled with black-and-white printed
labels. It is possible that the use of color-coded unit labels might reduce the
frequency of placing units in the wrong
location. The use of a computer-assisted inventory control system might also
reduce unit placement errors.
The error rate reported in this study
(0.12%) might seem excessive to some
individuals; however, it is possible that
the error rate observed may actually
be average or low relative to other facilities. Only with the publication of
data will objective comparisons between facilities be possible. Even if our
error rate is average or low, that is no
consolation, since any error, no matter
how infrequent, is unacceptable if it
can predispose to incompatible blood
transfusions. Because we were unable
to completely eliminate unit placement
errors, we conclude that frequent inventory inspection to detect the unit
placement errors should continue. Furthermore, each technologist must carefully check the group and type on each
unit label at the time of its selection.
We hope that this policy will reduce