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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5565_Библиотеки_им_академика_М_И_Перельмана.pdf
24 PRACTICAL SELF-ASSESSMENT FOR TRANSFUSION MEDICINE PROFESSIONALS
A. The reagent RBC panel is smaller and more focused (ie, contains fewer types of
group O RBCs) than the RBC panel used for the antibody detection test.
B. The method used for antibody identification is similar to that of antibody detec-
tion, and neither test requires an autocontrol using the patient’s red cells and
serum.
C. If the autocontrol is positive, then a repeat antibody detection test should be
performed.
D. If the DAT is negative, the patient’s red cells can be phenotyped for the corre-
sponding antigen.
E. If the DAT is negative, the autocontrol needs to be repeated.
D. If the DAT is negative, the patient’s red cells can be tested to ensure that the cor-
responding antigen is absent (thus, the patient is capable of making that alloanti-
body).
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夝
Question 7: Which of the following statements regarding the crossmatching of RBCs
is true?
A. Crossmatch testing involves mixing donor serum with the patient’s red cells.
B. Abbreviated crossmatching (immediate-spin phase only) should not be per-
formed under any circumstances.
C. Agglutination and/or hemolysis must occur during at least two of the three
phases for the unit to be considered crossmatch incompatible.
D. If crossmatch testing is performed, there is no need to do antibody screening on
the potential recipient.
E. AHG crossmatching detects antibodies directed against low-incidence antigens
on donor red cells that may not have been present on the red cells used in anti-
body identification testing.
E. Crossmatching involves mixing patient serum with donor red cells. Abbreviated
crossmatching (or electronic crossmatching under specific conditions) can be used if
the patient has no evidence of a current antibody or history of an antibody. If there is
agglutination or hemolysis at any of the crossmatch phases, the unit is considered
crossmatch incompatible. Antibody screening is performed along with crossmatch-
ing to detect weak antibodies that may not react when the donor cells have weak
antigen expression. Screen cells with strong antigen expression may detect this anti-
body that would not otherwise be detectable by crossmatching.
________________________________ _______________________________
夝
Question 8: Within how many days before transfusion should repeat testing be per-
formed for pregnant patients or patients transfused within the past 3 months?
PRETRANSFUSION COMPATIBILITY TESTING 25
A. 1
B. 3
C. 5
D. 7
E. 14
B. 3 days. If there is no evidence of an antibody being present currently or previ-
ously and the patient has not been recently transfused or pregnant, then a longer
period of 30 to 45 days between pretransfusion specimen and transfusion is com-
monly used.
________________________________ ________________________________
夝
Question 9: Which of the following is an indication to perform direct antiglobulin
testing (DAT)?
A. If the autocontrol is negative during antibody identification testing.
B. Possible transfusion reaction workup.
C. Possible neonatal alloimmune thrombocytopenia workup.
D. If both the antibody screen test and autocontrol are negative.
E. All of the above are indications to perform a DAT.
B. The direct antiglobulin test detects the presence of an antibody bound to patient
red cells. A positive autocontrol is an indication to perform a DAT. Other common
indications for DAT are to detect potential hemolytic disease of the fetus and new-
born (HDFN) and to work up a potential autoimmune hemolytic anemia.
________________________________ ________________________________
夝
Question 10: A patient has a positive autocontrol result during antibody identifica-
tion testing. Her DAT result is also positive. Which of the following pieces of infor-
mation is the LEAST helpful in determining the cause of her positive results?
A. Recent transfusion history of the patient.
B. Drug history of the patient.
C. Diagnosis.
D. Medical history.
E. Supplier qualification of the test kit manufacturer.
E. The finding of a positive DAT should trigger the obtaining of additional medical
history, including transfusion history (with particular attention to recent transfusion).
The patient’s drug history should also be examined, because many drugs can cause
a positive DAT.
26 PRACTICAL SELF-ASSESSMENT FOR TRANSFUSION MEDICINE PROFESSIONALS
________________________________ _______________________________
夝
Question 11: Three common types of antiglobulin reagent used to perform the DAT
are anti-IgG, anti-C3d, and polyspecific antiglobulin (a mixture of anti-IgG and anti-
C3d). Which statement about direct antiglobulin investigation is true?
A. If the DAT is not immediately positive after the addition of polyspecific anti-
globulin with anti-C3d an elution should not be performed.
B. The elution procedure is performed only if the DAT is positive with anti-C3d.
C. The elution procedure causes antigen to dissociate from the red cell surface so
that it can be identified in subsequent steps.
D. The elution procedure typically involves the addition of low ionic strength
saline solution to the patient’s red cells.
E. After the eluate is buffered, agglutination cannot be used to identify the anti-
body.
C. Bound IgG is best detected immediately after the addition of antiglobulin
reagents, whereas the 5-minute incubation at room temperature facilitates the detec-
tion of bound complement (C3d). If the DAT is positive with anti-IgG, regardless of
whether there is reactivity with anti-C3d, an elution procedure should be performed
to dissociate the antibody from the red cells and to allow the performance of anti-
body identification on the eluted antibody.
________________________________ _______________________________
夝
Question 12: A patient has broadly reactive antibodies (panagglutinin) during the
antiglobulin phase of antibody identification testing. Regarding the next step in the
patient’s workup, which statement is true?
A. An adsorption procedure is not necessary for this patient.
B. If the patient has been transfused recently, his/her autologous red cells can be
used to remove the autoantibodies.
C. Typically, only one adsorption step is necessary to remove 99% or more of the
autoantibodies present.
D. Polyethylene glycol is typically used to treat red cells before adsorption.
E. For patients who have been recently transfused, allogeneic or differential RBCs
of known antigenic composition must be used for the adsorption.
E. Allogeneic or differential adsorption should be used for patients who have been
recently transfused. The red cells used in this adsorption procedure are of defined
antigenic composition. Adsorption is often performed serially, because a single
adsorption step can be insufficient to remove autoantibodies.
PRETRANSFUSION COMPATIBILITY TESTING 27
________________________________ ________________________________
夝
Question 13: One method that can aid in the identification of an antibody involves
the incubation of panel RBCs with proteolytic enzymes, such as ficin. The net effect
is that some antigens are destroyed/inactivated resulting in no activity, while others
show enhanced activity. Which of the following antigens are destroyed/inactivated
by enzyme treatment?
A. Duffy.
B. Lewis.
C. Rh.
D. Kidd.
E. P1.
A. MNS and Duffy antigens are inactivated by enzyme treatment. Lewis, Kidd, Rh,
and P1 antibody reactivity is enhanced by enzyme treatment.
________________________________ ________________________________
夝
Question 14: Not only can antigens be inactivated, but specific antibody reactivity
can be markedly decreased from the patient’s serum by a process referred to as neu-
tralization. Which of the following is an example of neutralization?
A. Using saliva from a Lewis-positive individual to neutralize Lewis antigens on a
patient’s red cells.
B. Using fluid from echinococcus hydatid cysts to neutralize anti-P
1
in a patient’s
serum.
C. Using avian egg whites to remove HLA Class I antibodies.
D. Using chloroquine to remove Kell and Lutheran antibodies.
E. Using papain to remove ABO antibodies.
B. Neutralization refers to the inactivation of specific antibodies through the use cer-
tain specific neutralizing substances for example, the use of saliva from Lewis posi-
tive individuals to neutralize Lewis antibodies (not antigens as suggested in selection
A)
________________________________ ________________________________
夝
SUGGESTED READING
General
AABB, American Red Cross, America’s Blood Centers, and Armed Services Blood
Program. Circular of information for the use of human blood and blood compo-
nents. Bethesda, MD: AABB, 2008.
28 PRACTICAL SELF-ASSESSMENT FOR TRANSFUSION MEDICINE PROFESSIONALS
Carson TH, ed. Standards for blood banks and transfusion services. 27th ed.
Bethesda, MD: AABB, 2011.
Food and Drug Administration. Code of Federal Regulations, title 42, part 640.
Washington, DC: US Government Printing Office, 2011 (revised annually).
Roback JD, Grossman BJ, Harris T, Hillyer CD, eds. Technical manual. 17th ed.
Bethesda, MD: AABB, 2011.
Abbreviated (Immediate Spin) Crossmatch
Beck ML, Tilzer LL. RBC compatibility testing: A perspective for the future. Transfus
Med Rev 1996;10:118-30.
Heddle NM, O’Hoski P, Singer J, et al. A prospective study to determine the safety of
omitting the antiglobulin crossmatch from pretransfusion testing. Br J Haematol
1992;81:579-84.
Judd WJ. Are there better ways than the crossmatch to demonstrate ABO incompati-
bility? Transfusion 1991;31:192-4.
Meyer EA, Shulman IA. The sensitivity and specificity of the immediatespin cross-
match. Transfusion 1989;29:99-102.
Pinkerton PH, Coovadia AS, Goldstein J. Frequency of delayed hemolytic transfu-
sion reactions following antibody screening and immediate-spin crossmatching.
Transfusion 1992;32:814-17.
Rosen NR, Bates LH, Herod G. Transfusion therapy: Improved patient care and
resource utilization. Transfusion 1993;33:341-7.
Shulman IA, Meyer EA, Lam HT, Nelson JM. Additional limitations of the immediate
spin crossmatch to detect ABO incompatibility (letter). Am J Clin Pathol 1987;87:677.
Shulman IA, Nelson JM, Kent DR, et al. Experience with a cost-effective crossmatch
protocol. JAMA 1985;254:93-5.
Shulman IA, Nelson JM, Saxena S, et al. Experience with the routine use of an abbre-
viated crossmatch. Am J Clin Pathol 1984;82:178-81.
Presurgical Testing
AuBuchon JP. Blood transfusion options: Improving outcomes and reducing costs.
Arch Pathol Lab Med 1997;121:40-7.
Cousins LM, Teplick FB, Poeltler DM. Pre-cesarean blood bank orders: A safe and
less expensive approach. Obstet Gynecol 1996; 87:912-16.
Ransom SB, McNeeley SG, Hosseini RB. Cost-effectiveness of routine blood type
and screen testing before elective laparoscopy. Obstet Gynecol 1995;86:346-8.
Electronic Crossmatch
Butch S for the Scientific Section Coordination Committee. Guidelines for imple-
menting an electronic crossmatch. Bethesda, MD: AABB, 2003.
PRETRANSFUSION COMPATIBILITY TESTING 29
Riccardi D, Giovanetti AM, Parravicini A, et al. Risk of ABO and non-ABO incom-
patibility using type and screen and electronic crossmatch (abstract). Transfusion
1991;31:60S.
Shulman IA, Kent D. Safety in transfusion practice: Is it safe to eliminate the major
crossmatch for selected patients? Arch Pathol Lab Med 1989;113:270-2.
Role of the Autocontrol and DAT in Routine Testing
Judd WJ, Barnes BA, Steiner EA, et al. The evaluation of a positive direct antiglobu-
lin test (autocontrol) in pretransfusion testing revisited. Transfusion 1986;26:220-4.
Judd WJ, Oberman HJ, Steiner EA, Baure RC. The evaluation of a positive direct
antiglobulin test in pretransfusion testing. Transfusion 1980;20:17-23.
Stec N, Shirey RS, Smith B, et al. The efficacy of performing RBC elution studies in
pretransfusion testing of patients with positive direct antiglobulin tests. Transfusion
1986;26:225-6.
Risk of D Immunization in Rh-Negative Recipients of Rh-Positive RBCs
Frohn C, Dumbgen L, Brand JM, et al. Probability of anti-D development in D–
patients receiving D+ RBCs. Transfusion 2003;43:893-8.
Ramsey G, Hahn LF, Cornell FW, et al. Low rate of Rhesus immunization from Rh-
incompatible blood transfusions during liver and heart transplant surgery. Trans-
plantation 1989;47:993-5.
Schmidt PJ, Leparc G, Samia CT. Use of Rh positive blood in emergency situations.
Surg Gynecol Obstet 1988;167:229-33.
Platelet Transfusion: ABO and Rh Issues
International Forum: Transfusion of apheresis platelets. Vox Sang 2006;88:207-21.
Josephson CD, Mullis NC, Van Demark C, Hillyer CD. Significant numbers of
apheresis-derived group O platelet units have “high titer” anti-A/A,B: Implications
for transfusion. Transfusion 2004;44:805-8.
Larsson LG, Welsh VJ, Ladd DJ. Acute intravascular hemolysis secondary to out-of-
group platelet transfusion. Transfusion 2000;40:902-6.
Lin Y, Callum JL, Coovadia AS, Murphy PM. Transfusion of ABO-nonidentical plate-
lets is not associated with adverse outcomes in cardiovascular surgery patients.
Transfusion 2002;42:116-72.
Lozano M, Cid J. The clinical implications of platelet transfusion associated with
ABO or Rh(D) incompatibility. Transfus Med Rev 2003;17:57-68.
Menitove JE. Immunoprophylaxis for D– patients receiving platelet transfusions from
D– donors? (editorial) Transfusion 2002;42:136-8.
In: Leonard G, Licata M.
Practical Self-Assessment for Transfusion Medicine Professionals
Bethesda, MD: AABB Press, 2012
4
Carbohydrate Blood Group
Antigens and Collections
QUESTIONS
Question 1: Which choice below is correctly matched?
A. O gene – encodes a fucosyltransferase that adds a fucose molecule to the pre-
existing oligosaccharide precursor.
B. A gene – encodes a glycosyltransferase that adds an N-acetylgalactosamine to
the pre-existing oligosaccharide precursor.
C. B gene – encodes a glycosyltransferase that adds an N-acetylgalactosamine to
the pre-existing oligosaccharide precursor.
D. H gene – encodes a fucosyltransferase that adds a galactose molecule to the
pre-existing oligosaccharide precursor.
E. Se gene – encodes a glucosyltransferase that adds a glucose molecule to the
pre-existing oligosaccharide precursor.
________________________________ ________________________________
夝
Question 2: Which of the following statements about the ABO system is true?
A. The A and B genes have very little nucleotide sequence homology.
B. Anti-A and anti-B are naturally occurring, and are thought to be produced in
response to maternal poteins early in life.
C. In the absence of red cell exposure, levels of anti-A and anti-B continue to rise
throughout childhood and adulthood, reaching a peak in the sixth or seventh
decades.
D. Hemolytic disease of the fetus and newborn occurs more commonly in group
O mothers of Group A or B fetuses.
E. A
1
individuals have an A antigen that is similar to that of A
2
individuals.
32 PRACTICAL SELF-ASSESSMENT FOR TRANSFUSION MEDICINE PROFESSIONALS
________________________________ _______________________________
夝
Question 3: Which statement is true about ABO typing of patients?
A. A
2
patients have a transferase (enzyme) that is less efficient at adding a sugar
residue than A
1
patients.
B. The vast majority of group A patients belong to subgroup A
2
.
C. About 90% of subgroup A
2
patients produce anti-A
1
.
D. In the event that there is a discrepancy between the ABO forward and reverse
typing, and emergency blood must be issued, group O-positive blood should
be given.
E. H-deficient (Bombay) phenotype is the universal recipient.
________________________________ _______________________________
夝
Question 4: Choose the most likely cause for the ABO forward and reverse typing
discrepancy based on the following information: forward typing indicates group A;
reverse typing indicates the presence of anti-A and anti-B.
A. Acquired B phenotype.
B. Individual is subgroup A
2
.
C. Individual is a newborn or elderly patient.
D. Individual has hypogammaglobulinemia.
E. None of the above could explain these results.
________________________________ _______________________________
夝
Question 5: ABO typing consists of forward (or front) and reverse (or back) typing
reactions. Why are A
1
RBCs used in reverse typing?
A. A
1
patient’s serum may contain anti-A
1
.
B. A
2
patient’s serum may contain anti-A
3
.
C. A
1
RBCs have the strongest expression of A antigen.
D. A
1
RBCs have the weakest expression of A antigen.
E. None of the above.
________________________________ _______________________________
夝
Question 6: Which of the following statements is true about patients with the H-
deficient (Bombay) phenotype?
A. These individuals express the H gene (FUT1), which encodes a fucosyltransfer-
ase.
CARBOHYDRATE BLOOD GROUP ANTIGENS AND COLLECTIONS 33
B. These individuals express the “secretor gene” (FUT2), which encodes a fuco-
syltransferase.
C. These individuals forward and reverse type as group O.
D. These patients should be given group O RBCs if transfusion is needed.
E. Because these individuals do not carry normal A and B genes, their children
can have only group O or Bombay phenotypes.
________________________________ ________________________________
夝
Question 7: Which statement about the Ii blood group system is true?
A. I and i antigens are protein antigens encoded by two different alleles of the
same gene.
B. The i antigen is unbranched and predominates on adult red cells, whereas the I
antigen is branched and predominates on neonatal red cells.
C. Patients with “marrow stress” conditions have increased i antigen on their red
cells.
D. Cold agglutinin disease (cold autoimmune hemolytic anemia) may occur in
patients who lack anti-I.
E. Anti-I autoantibodies are associated with EBV infection; anti-i autoantibodies
are associated with mycoplasma infection.
________________________________ ________________________________
夝
Question 8: Which statement about the Lewis system is true?
A. Lewis antigens are intrinsic to the red cell membrane.
B. The Lewis (Le) gene encodes a fucosyltransferase that adds only fucose to
secreted type I oligosaccharide chains; this same gene is present in Le(a+) and
Le(b+) individuals.
C. The Le
a
antigen can be made only by secretors, whereas the Le
b
antigen can be
made only by nonsecretors.
D. Lewis antigens can be lost from red cells in patients with infectious mononu-
cleosis and pancreatitis, but persist in those with severe alcoholic cirrhosis.
E. The transfused patient cannot assume the Lewis phenotype of the donor.
________________________________ ________________________________
夝
Question 9: A patient who requires a RBC transfusion is found to have anti-Le
a
.
Which of the following statements about anti-Le
a
is FALSE?
A. Le
a
antibodies that are reactive at 37 C and reactive at 4 C may cause severe
hemolysis.
B. Most Le
a
antibodies are not clinically significant.
34 PRACTICAL SELF-ASSESSMENT FOR TRANSFUSION MEDICINE PROFESSIONALS
C. Le
a
antibodies are not associated with hemolytic disease of the fetus and newborn.
D. The transfused RBCs for this patient must be crossmatch-compatible.
E. The transfused RBCs for this patient must be Le
a
antigen-negative.
________________________________ _______________________________
夝
Question 10: Which of the following statements about the globoside (GLOB) blood
group antigen is NOT true?
A. The P
k
antigen is the immediate precursor to the P antigen, which is formed by
the addition of an N-acetylgalactosaminyl residue to the terminal galactosyl
residue of P
k
.
B. The P antigen is a high-incidence antigen in the population; it is absent in only
1 in 100,000 individuals.
C. Although rare, P antibodies are clinically significant IgM antibodies because
they can cause hemolytic transfusion reactions.
D. The P antigen is a receptor for EBV.
E. The P antigen is a receptor for nephritogenic E. coli.
________________________________ _______________________________
夝
Question 11: Which antibody binds to red cells in the colder areas of the body and
then causes hemolysis as the cells circulate to the warmer central areas of the body
(paroxysmal cold hemoglobinuria)?
A. Donath-Landsteiner antibody (auto-anti-P IgG).
B. Anti-Ulex.
C. Anti-PIGA.
D. Anti-HP1a.
E. Paroxysmal cold hemoglobinuria is not antibody-based.
________________________________ _______________________________
夝
ANSWERS
Question 1: Which choice below is correctly matched?
A. O gene – encodes a fucosyltransferase that adds a fucose molecule to the pre-
existing oligosaccharide precursor.
B. A gene – encodes a glycosyltransferase that adds an N-acetylgalactosamine to
the pre-existing oligosaccharide precursor.