Blood Bank BOC 101-200
Based upon Kleihauer-Betke test results, which of the following formulas is used to determine the volume of fetomatemal hemorrhage in mL of Whole Blood?
% fetal cells present*50
The rosette test will detect a FMH as small as
10 mL
A Kleihauer-Betke stain of a postpartum blood film revealed a 0.3% fetal cells. What is the estimated volume of the fetomaternal hemorrhage expressed as whole blood?
15
What is the approximate probability of finding compaitbel blood amoun random Rh positive units for a patient who has anti-c and anti-K? (consider that 20% of Rh positive donors lack c and 90% lack K)
18%
The results of a Kleihauer-Betke stain indicate a fetomaternal hemorrhage of 35 mL of whole blood. How many vials of Rh immune globulin would be required?
2
A fetomaternal hemorrhage of 35 mL of fetal Rh-positive packed RBCs has been detected in an Rh-negative woman. How many vials of Rh immune globulin should be given?
3
An acid elution stain was made using a 1-hour postdelivery maternal blood sample. Two thousand cells were counted and thirty of these cells appeared to contain fetal hemoglobin. It is the policy of the medical center to add one vial of Rh immune globulin to the calculated dose when the estimated volume of the hemorrhage exceeds 20 mL of whole blood. Calculate the number of vials of Rh immune globulin that would be indicated under these circumstances.
4
A patient is group O, Rh negative with anti-D and anti-K in her serum. What percentage of the general Caucasian donor population would be compatiable with this patient?
6.0
What percent of group O donors would be compatible with a serum sample that contained anti-X and anti-Y if X antigen is present on red cells of 5 of 20 donors, and Y antigen is present on red cells of 1 of 10 donors?
68%
Anti-K is identified in a patient's serum. If random crossmatches are performed on 10 donor units, approximately how many would be expected to be compatiable?
9
Which of the following is responsible for the production of blood group antibodies?
B cells
IgG sensitized red cells that activate complement may not complete complement activation to cell lysis. In addition to IgG on the surface of these red cells, what complement component is present?
C3b
The MAC formed during activation of complement via the classical pathway consists of
C5b-C9
Transfusion of which of the following is needed to help correct hypofibrinogenemia due to DIC?
Cryoprecipitate AHF
Which of the following blood group antigens is the most immunogenic, or has the greatest ability to initiate antibody production in an individual who lacks the antigen?
D
The following results were obtained (figure 4). Which of the following is the most probable explanation for these results?
Rh HDFN, infant has a false-negative Rh typing
ABO hemolytic HDFN differs from Rh HDFN in that
Rh HDNF is clinically more severe than ABO NHDF
An obstetrical patient has had 3 previous pregnancies. Her first baby was healthy, the second was jaundiced at birth and required an exchange transfusion, while the third was stillborn. Which of the following is the most likely cause?
Rh incompatability
In a case of cold agglutinin disease, the patient serum would most likely react 4+ at immediate spin with
all cells of a group O cell panel and his own cells
While performing routine postpartum testing for an RhIG candidate, a weaklu positive antibody screening test was found. Anti-D was identified. This antibody is most likely a result of
antenatal administration of RHIG at 28 weeks gestation
The DAT in a suspected case of WAIHA is positive. Which of the following monospecific reagents would be used in further DAT testing?
anti-C3d
RhIG administration would NOT be indicated in an Rh-negative woman who has a
anti-D titer of 1:4096
Polyspecific AHG reagent contains
anti-IgG and anti-C3d
A specimen of cord blood is submitted to the transfusion service for routine testing. The following results are obtained: Anti-A= 4+ Anti-B= 0 Anti-D= 3+ Rh control=0 DAT=2+ It is known that the father is group B with the genotype of cde/cde. Of the following antibodies, which one is most likely cause of the positive DAT?
anti-c
In which of the following is the IAT test utilized
antibody detection (screening) test
Pathologic cold autoantiboies differ from benign cold autoantibodies in
antibody titer
Which of the following is characteristic of anti-i: associated with WAIHA found in the serum of individuals with infectious mono detected at lower temperatures in the serum of normal individuals found only in the serum of group O individuals
found in the serum of individuals with infectious mono
Phagocytosis is a function of
granulocytes
Immunoglobulin classes are differentiated according to the molecular structure of
heavy chains
Anti-Fya is capable of causing
hemolytic transfusion reactions
The purpose of performing antibody titers on serum from an immunizaed, pregnant woman is to
identify candidates requiring additional fetal monitoring
A 4+ positive reaction using gel technology will appear as red blood cells
in a layer at the top of the gel media
The following results are seen on a maternal postpartum sample: anti-D= 0 D control=0 weak D=1+mf weak D control=0 The most appropriate course of action is to
investigate FMH
To prevent GVHD RBCs prepared for infants who have received intrauterine transfusions should be
irradiated
Blood selected for exchange transfusion must:
lack RBC antigens corresponding to maternal antibodies
Which of the following is the preferred specimen for the initial compatibility testing in exchange transfusion therapy?
maternal serum
Which of the following cells is the largest cell in the bone marrow
megakaryocytes
Which of the following would be the best source of platelets for transfusion in the case of alloimmune neonatal thrombocytopenia?
mother
Refer to the following information in Figure 5. What is the best interpretation for the laboratory data given?
mother has a larger FMH than normal
Criteria determining Rh immune globulin eligibility include:
mother has not been previously immunized to the D antigen
In patients who present with bleeding due to low platelet count, the most common type of bleeding is
mucosal bleeding
A false negative DAT can be the result of
neutralization of AHG reagent
Blood typing after a normal labor and delivery showed that the mother is group A, D negative and demonstrates anti-D in her seum. Her slightly gaundiced newborn is anemic and types as group ), D negative iwht a 4+ DAT. Previous lab work showed that the father was grou pO, D-positive. From the information given, which test results is questionable?
newborn D type
A 40 year old man with autoimmune hemolytic anemia due to anti-E has a hemoglobin level of 10.8g/L. The patient will most likely be treated with
no transfusion
What is linkage disequilibrium in reference to HLA haplotype?
occurrence of HLA genes in the same haplotype more often than would be expected based on the gene frequences
A false positive IAT can be the result of
overcentrifugation
monoclonal blood banking reagents have which of the following as a disadvantage
overspecificity
The following ABO results are noted on a sample from a 90 year old male admitted to the ER for possible GI bleeding. Anti-A=0 Anti-B=0 A1 cells=0 B cells=1+ What might be a likely explanation for these results?
patient's age
A newborn demonstrates petechiae, ecchymosis, and mucosal bleeding. The preferred blood component for this infant would be:
platelets
The immune response to red cell antigens with numerous epitopes results in a heterogenous population of antibodies referred to as
polyclonal
Appropriate antigen-antibody ratios are important to avoid an excess of unbound antibody, known as
prozone
Four units of blood are needed for elective surgery. The patients serum contains anti-C, anti-e, anti-FYa, and anti-JKb. Which of the following would be the best source of donor blood?
rare donor registry
Which of the following is characteristic of anti-i often associated with HDFN reacts best at room temperature reacts best at 37'C is usually IgG
reacts best at room temperature
What is the most common clinical incident that results in alloantibody production?
red cell transfusion
LISS acts as an enhancement medium and faicliates antibody uptake by
reducing zeta potential
In the normal adult, the spleen acts as a site for
removal of imperfect and aging cells
One of the advantages of performing antibody screening studies using gel technology is
saline washing is not required
The Kell antigen is
strongly immunogenic
Blood group antigen and antibody hemagglutination reactions are influenced by
temperature
ABO-hemolytic disease of the newborn is seen in
the newborn of group O mothers
The following panel results were obtained with the serum of a paitent from the prenatal clinic (figure 3) To evaluate potential risk to the fetus, what addition studies should be performed?
treat serum with dithiothreitol and repeat panel
Many enhancement media used in the blood bank promote hemagglutination in the presence of IgG antibodies by reducing:
zeta potential
A blood component used in the treatment of hemophilia A is
factor VIII
Which unit should be selected for exchange transfusion if the newborn is group A, Rh-positive and the mother is group A, Rh-positive with anti-c?
A, CDe/CDe
A gropu A, Rh positive infant of a group O, Rh positive mother has a weakly positive DAT and a moderately elevated bilirubin 12 hours after birth. The most likely cause is
ABO incompatibility
Which of the following reagents is used to facilitate hemagglutination following the sensitization of re cells with an IgG alloantibody?
AHG
The addition of antibody-sensitized red cells (check cells) to all negative AHG tests ensure that
AHG reagent was added to each test
Resistance to malaria is best associated with which of the following blood groups?
Duffy
which of the following blood group antibodies will no longer react with its respective antigens once those antigens are treated with proteolytic enzymes?
Duffy, M, N, Xga
A unit of FFP was inadvertently thawed and the immediately refrigerated at 4'C on Monday morning. On Tuesday evening, this unit may still be transfused as a replacement for
Factor 9
which of the following structures of an immunoglobulin molecule is involved in the activation of complement via the classical pathway?
Fc region
Proteolytic enzyme treatment of red cells destroy which antigens?
Fy, M, N, Xga
In which of the following clinical situations will the DAT be positive?
HDFN
Cold agglutinin disease is associated with an antibody specificity toward which of the following?
I
The antibodies of the Kidd system react best at
IAT
Which immunoglobulins cross the placenta?
IgG
macrophages and monocytes have Fc receptors for which of the following?
IgG
fetal neonatal alloimmune thrombocytopenia is caused by which of the following maternal antibodies?
IgG alloantibodies against HPA antigens
The DAT in a patient with WAIHA is most often positive for
IgG and C3
Which of the following pairs of immunoglobulins is most efficient at activating complement via the classical pathway?
IgG1 and IgG3
In a primary immune response, which immunoglobulin class appears first?
IgM
Which of the following immunoglobulins is most efficient at activating complement via the classical pathway?
IgM
Which of the following immunoglobulins is most efficient at causing direct hemagglutination?
IgM
In CGD, granulocyte function is impaired. An association exists between this clinical condition and a depression of which of the following antigen?
Kell
Which of the following antigens is most likely to be involved in HDFN?
Kell
A blood specimen from a pregnant woman is found to be gorpu B, Rh negative and the serum contains anti-D with a titer of 512. What would eb most appropriate type of blood to have availbable for a possible exchange transfusion for her infant?
O, Rh negative
Laboratory studies of maternal and cord blood yiled the following results: Maternal blood= O, Rh negative with anti-E in serum Baby= B, Rh positive, 2+ DAT, and anti-E in eluate. If exchange transfusion is necessary, the best choice of blood is
O, Rh positive, E-
A mother is group A, with anti-D in her serum. What would be the preferred blood product if an intrauterine transfusion is indicated?
O, Rh-negative RBCs, irradiated, CMV safe, HgB-S negative
A 25 y.o Caucasian woman, gravida 3, para 2, required 2 units of red blood cells. the antibody screen was positive and the results of the antibody panel are in Figure 2. What is the most probable genotype of this patient?
R1R1
When the main objective of an exchange transfusion is to remove the infants antibody-sensitized red blood cells and to control hyperbilirubinemia, the blood product of choice is ABO compatible:
RBCs suspended in FFP
A negative result using solid phase adherence assays will demonstrate indicator red cells as
a red blood cell pellet in the bottom of the well
In treating hyperbilirubinemia in HDFN, light phototherapy is used to
breakdown unconjugated bilirubin to a nontoxic isomer
IgG antibody and/or C3b sensitized red blood cells can be phagocytosed by zells in the reticuloendothelial system. This phenomena is clinically recognized as:
extravascular hemolysis
In ABO hemolytic transfusion reactions, complement is activated via which of the following pathways?
classical
In suspected cases of HDFN, what significant information can be obtained from the baby's blood smear?
determination of the presence of spherocytes
In cases where antepartum RHIG has been administered and anti-D is deteccted in the mother's serum at deliver, what laboratory stiduesi may help determine if the anti-D is from the antepartum RHIG, or due to amternal alloimmunization
determine antibody titer of maternal D
What is the most important consideration for a patient requiring red cell transfusion due to severe anemia when their serum contains a warm autoantibody?
determining the presence of underlying autoantibodies
Some blood group antibodies may react stronger with red cells of individuals who have inherited 2 identical alleles for the antigen to which the antibody is directed. This is known as:
dosage effect
Which of the following Rh antigens has the highest frequence in Caucasians?
e
Which of the following cells transports O2 and CO2?
erythrocytes
