Blood bank - serology
a Treating autologous cells with a proteolytic enzyme such as ficin enhances the adsorption of the cold reactive antibody.
In a cold autoadsorption procedure, pretreatment of the patient's red cells with which of the following reagents is helpful? a. ficin b. phosphate-buffered saline at pH 9.0 c. low ionic strength saline (LISS) d. albumin
d Weak antibodies may be missed if there are excess RBC antigens as there may be too few antibodies to bind to red cell antigens.
Which of the following might cause a false negative indirect antiglobulin test (IAT)? a. over-reading b. IgG-coated screening cells c. addition of an extra drop of serum d. too heavy a cell suspension
b Acquired B occurs in group A individuals and is due to deacetylation of the A antigen by bacterial enzymes. Detection of acquired B is dependent upon the source of anti-B used.
Which of the following patient data best reflects the discrepancy seen when a person's red cells demonstrate the acquired - B phenotype? Forward grouping Reverse grouping patient A B O patient B AB A patient C O B patient D B AB a. A b. B c. C d. D
b In cold agglutinin syndrome, anti-I acts as a complement binding antibody with a high titer and high thermal amplitude. The complement cascade is activated and C3d remains on the red cell membrane of circulating cells.
Anti-I may cause a positive direct antiglobulin test (DAT) because of: a. anti-I agglutinating the cells b. C3d bound to the red cells c. T-activation d. C3c remaining on the red cells after cleavage of C3b
c The ABO discrepancy is most likely due to anti-H in an A1 individual. Anti-H reacts most strongly at room temperature with group O screening cells and weaker or negative at room temperature with autologous or donor group A1 cells. As the branched H structures are converted to A, some group A1 individuals may develop a clinically significant anti-H recognizing H structures on group O and A2 blood groups.
Refer to the following data: Forward group: Reverse group: anti-A anti-B anti-A1 lectin A1 cells A2 cells B cells 4+ 0 4+ 0 2+ 4+ Which of the following antibody screen results would you expect with the ABO discrepancy seen above? a. negative b. positive with all screen cells at the 37C phase c. positive with all screen cells at the RT phase; autocontrol is negative d. positive with all screen cells and the autocontrol cells at the RT phase
a Chido antibodies are considered clinically insignificant
Transfusion of Ch+ (Chido-positive) red cells to a patient with anti-Ch has been reported to cause: a. no clinically significant red cell destruction b. clinically significant immune red cell destruction c. decreased ^51Cr red cell survival d. febrile transfusion reactions
a The patient has a negative antibody screen, but one unit is found to be incompatible. The antibody is most likely directed towards a low-incidence antigen.
A 42 year old female is undergoing surgery tomorrow and her physician requests that 4 units of RBCs be crossmatched. The following results were obtained: IS 37C IAT screening cell I 0 0 0 screening cell II 0 0 0 screening cell III 0 0 0 Crossmatch IS 37C IAT donor 1: 2+ 1+ 1+ donors 2,3,4: 0 0 0 What is the most likely cause of the incompatibility of donor 1? a. single alloantibody b. multiple alloantibodies c. Rh incompatibilities d. donor 1 has a positive DAT
c Secretor studies demonstrates the presence of a substance by the observation of neutralizaton of the corresponding antibody. Nonreactivity with B and O cells indicates B and H substances are present in the saliva so the red cells from this person are group B.
A person's saliva incubated with the following antibodies and tested with the appropriate A2, O, and B indicator cells, gives the following test results: Antibody specificity Test results anti-A reactive anti-B inhibited anti-H inhibited The person's red cells ABO phenotype is: a. A b. AB c. B d. O
b Anti-Fya may cause mild to rarely severe hemolytic disease of the fetus and newborn.
A pregnant woman has a positive antibody screen and the panel results are given below: EM Enzyme Cell D C c E e K Jka Jkb Fya Fyb Lea Leb M N P1 37C AHG AHG 1 + + 0 0 + + + + 0 + 0 + + + + 0 0 0 2 + + 0 0 + 0 + 0 + 0 0 + + 0 0 1+ 2+ 0 3 + 0 + + 0 0 + + + + 0 + + + + 0 1+ 0 4 + + + 0 + 0 0 + 0 + 0 + + 0 + 0 0 0 5 0 0 + 0 + 0 + + + + 0 + + 0 0 0 1+ 0 6 0 0 + + + 0 + 0 0 0 + 0 + + 0 0 0 0 7 0 0 + 0 + + + + 0 + + 0 + + + 0 0 0 8 0 0 + 0 + 0 0 + + 0 0 + 0 + + 1+ 2+ 0 auto: 0 0 0 What is the association of the antibody (ies) with hemolytic disease of the newborn (HDN)? a. usually fatal HDFN b. may cause HDFN c. is not associated with HDFN d. HDFN cannot be determined
b If a patient is negative for clinically significant antibodies, and a single crossmatch is incompatible, the incompatibility is either due to donor cells with a positive DAT or the patient has an antibody to a low-incidence antigen tat the donor's cells possess.
A reason why a patient's crossmatch may be incompatible while the antibody screen is negative: a. the patient has an antibody against a high-incidence antigen b. the incompatibility donor unit has a positive direct antiglobulin c. cold agglutinins are interfering in the crossmatch d. the patient's serum contains warm autoantibody
c Dolicho biflorus plant seed extract forms complexes with N-acetylgalactosamine. When properly diluted, it can distinguish between A1 donor cells and other subgroups of A.
A sample gives the following results: Cells with: Serum with: anti-A 3+ A1 cells 2+ anti-B 4+ B cells 0 Which lectin should be used first to resolve this discrepancy? a. Ulex europaeus b. Arachis hypogaea c. Dolichos biflorus d. Vicia graminea
c AHG control cells are IgG-sensitized cells that react with the anti-IgG in the AHG reagent to demonstrate AHG was added and not neutralized by insufficient washing of the tests prior to its addition.
AHG (Coombs) control cells: a. can be used as a positive control for anti-C3 reagents b. can be used only for the indirect antiglobulin test c. are coated only with antibody d. must be used to confirm all positive antiglobulin reactions
a Lewis antibodies may bind complement and fresh serum that contains anti-Lea may hemolyze Le(a+) red cells in vitro. Approximately 22% of the population is Le(a+)
An antibody that causes in vitro hemolysis and reacts with the red cells of 3 out of ten crossmatched donor units is most likely: a. anti-Lea b. anti-s c. anti-k d. anti-E
b The absence of agglutination at the AHG phase with screening cells and agglutination with one of 3 donor units is most likely due to an antibody to a low-incidence antigen
At the indirect antiglobulin phase of testing there is no agglutination between patient serum and screening cells one of 3 donor units was incompatible. The most probable explanation for these finding is that the: a. patient has an antibody directed against a high incidence antigen b. patient has an antibody directed against a low incidence antigen c. donor has an antibody directed against donor cells d. donor has a positive antibody screen
a Warm autoantibodies often exhibit Rh specificity.
Autoantibodies demonstrating blood group specificity in warm autoimmune hemolytic anemia are associated more often with which blood group system? a. Rh b. I c. P d. Duffy
c Warm serum and reagent red cells to 37C before repeating ABO typing will decrease/eliminate reactivity of cold autoantibody.
Consider the following ABO typing results: Patient's cells vs: Patient's serum vs: anti-A anti-B A1 cells B cells 4+ 0 1+ 4+ Additional testing was performed using patient serum: IS RT screening cell I 1+ 2+ screening cell II 1+ 2+ autocontrol 1+ 2+ What should be done next? a. test serum against a panel of group O cells b. neutralization c. perform serum type at 37C d. elution
c Presence of agglutination with A1 cells, screening cells and autocontrol at IS and RT is indicative of a cold autoantibody.
Consider the following ABO typing results: Patient's cells vs: Patient's serum vs: anti-A anti-B A1 cells B cells 4+ 0 1+ 4+ Additional testing was performed using patient serum: IS RT Screening cell I 1+ 2+ Screening cell II 1+ 2+ Autocontrol 1+ 2+ What is the most likely cause of this discrepancy? a. A2 with anti-A1 b. cold alloantibody c. cold autoantibody d. acquired - A phenomenon
c A negative reaction after the addition of check cells indicates AHG serum was not present. Inadequate washing of red cells may leave residual patient serum behind, which can neutralize AHG serum.
Crossmatch results at the antiglobulin phase were negative. When 1 drop of check cells was added, no agglutination was seen. The most likely explanation is that the: a. red cells were overwashed b. centrifuge speed was set too high c. residual patient serum inactivated the AHG reagent d. laboratorian did not add enough check cells
c Emergent release of blood can not use previous records. Blood typing must be performed on the current sample. In this case, group O Rh-negative is the best choice since there is evidence the patient is Rh-negative
During emergency situations when there is no time to determine ABO group and RH type on a current sample for transfusion, the patient is known to be A, Rh negative. The technologist should: a. refuse to release any blood until the patient's sample has been typed b. release A Rh-negative rbcs c. release O Rh-negative rbcs d. release O Rh-positive rbcs
c Soluble forms of some blood group antigens can be prepared from other sources and used to inhibit reactivity of the corresponding antibody. such as the HTLA antibodies anti-Ch and anti-Rg. Most HTLA antibodies, although weakly reactive in undiluted serum, will continue to react weakly at higher dilutions.
Of the following, the most useful technique(s) in the identification and classification of high-titer, low-avidity (HTLA) antibodies is/are: a. reagent red cell panels b. adsorption and elution c. titration and inhibition d. cold autoadsorption
b The K antigen is integral to the red cell membrane and would not change in a patient. Errors in typing or patient identification may be detected when discrepancies are found when comparing historical records.
On Monday, a patient's K antigen typing result was positive. Two days later, the patient's K typing was negative. The patient was transfused with 2 units of Fresh Frozen Plasma. The tech might conclude that the: a. transfusion of FFP affected the K typing b. wrong patient was drawn c. results are normal d. anti-K reagent was omitted on Monday
b Polyspecific AHG contains anti-IgG and anti-C3d
Polyspecific reagents used in the direct antiglobulin test should have specificity for: a. IgG ad IgA b. IgG and C3d c. IgM and IgA d. IgM and C3d
d Results of ABO and Rh testing on a current specimen must always be compared to that of a previous transfusion period. Errors in typing or patient identification may be detected when discrepancies are found. Collection of a new sample allows determination of which sample was incorrectly collected.
Samples from the same patient were received on 2 consecutive days. Test results are summarized below: Day #1 Day #2 anti-A 4+ 0 anti-B 0 4+ anti-D 3+ 3+ A1 cells 0 4+ B cells 4+ 0 Ab screen 0 0 How should the request for crossmatch be handled? a. crossmatch A, Rh-positive units with sample from day 1 b. crossmatch B, Rh-positive units with sample from day 2 c. crossmatch AB, Rh-positive units with both samples d. collect a new sample and repeat the tests
c Ax cells react more strongly with anti-A,B than with anti-A. If anti-A is nonreactive, Ax may be detected with anti-A,B
The purpose of testing with anti-A,B is to detect: a. anti-A1 b. anti-A2 c. subgroups of A d. subgroups of B
a The Donath-Landsteiner test is diagnostic for PCH. The antibody is IgG and is biphasic: hemolysis occurs when the antibody is incubated with cells and cold temperatures and then incubated at 37C. Often the antibody demonstrates specificity towards the high-incidence antigen P (not to be confused with P1). The antibody screen is usually negative and the patient's red cells are coated with complement.
A 10 yr old girl was hospitalized because her urine had a distinct red color. The patient had recently recovered from an upper respiratory infection and appeared very pale and lethargic. Tests were performed with the following results: hemoglobin: 5 g/dl (50g/L) reticulocyte count: 15% DAT: weak reactivity with poly-specific and anti-C3d; anti-IgG was negative antibody screen: negative Donath-Landsteiner test: positive; P-cells showed no hemolysis The patient probably has: a. paroxysmal cold hemoglobinuria (PCH) b. paroxysmal nocturnal hemoglobinuria (PNH) c. warm autoimmune hemolytic anemia d. hereditary erythroblastic multinuclearity with a positive acidified serum test (HEMPAS)
d The strength of agglutination is dependent upon optimal antigen to antibody ratio. Excessive amount of antigen does not allow maximal uptake of antibody per red cell and therefore agglutination is negatively affected leading to weaker or negative results.
A 10% red cell suspension in saline is used in a compatibility test. Which of the folowing would most likely occur? a. a false-positive result due to antigen excess b. a false-positive result due to the prozone phenomenon c. a false-negative result due to the prozone phenomenon d. a false-negative result due to antigen excess
d Antibodies to C, Leb, and Jka can be eliminated due to the lack of agglutination with panel cells 1 and 2. Panel cells 1 and 2 possessed the C, Leb and Jka antigens. Only anti-E antigens remain.
A 25 year old Caucasian woman, gravida 3, para 2, required 2 units of RBCs. The antibody screen was positive and the results of the antibody panel are shown below: EM Cell D C c E e K Jka Jkb Lea Leb M N P1 37C AHG 1 + + 0 0 + + + + 0 + + + + 0 0 2 + + 0 0 + 0 + 0 0 + + 0 0 0 0 3 + 0 + + 0 0 + + 0 + + + + 0 1+ 4 + + + 0 + 0 0 + 0 + + 0 + 0 1+ 5 0 0 + 0 + 0 + + 0 + + 0 0 0 1+ 6 0 0 + + + 0 + 0 + 0 + + 0 0 1+ 7 0 0 + 0 + + + + + 0 + + + 0 1+ 8 0 0 + 0 + 0 0 + 0 + 0 + + 0 1+ auto: 0 Which common antibody has not been rule out by the panel? a. anti-C b. anti-Leb c. anti-Jka d. anti-E
b Anti-K and anti-P1 can be ruled out on cell 1 since there is no agglutination of cell 1 with the patient's sample. Anti-M and anti-Jka can be eliminated on cell 2, which has a double - dose antigen expression of both M and Jka
A 25 year old Caucasian woman, gravida 3, para 2, required 2 units of RBCs. The antibody screen was positive and the results of the antibody panel are shown below: EM Cell D C c E e K Jka Jkb Lea Leb M N P1 37C AHG 1 + + 0 0 + + + + 0 + + + + 0 0 2 + + 0 0 + 0 + 0 0 + + 0 0 0 0 3 + 0 + + 0 0 + + 0 + + + + 0 1+ 4 + + + 0 + 0 0 + 0 + + 0 + 0 1+ 5 0 0 + 0 + 0 + + 0 + + 0 0 0 1+ 6 0 0 + + + 0 + 0 + 0 + + 0 0 1+ 7 0 0 + 0 + + + + + 0 + + + 0 1+ 8 0 0 + 0 + 0 0 + 0 + 0 + + 0 1+ auto: 0 0 Which of the following antibodies may be the cause of the positive antibody screen? a. anti-M and anti-K b. anti-c and anti-E c. anti-Jka and anti-c d. anti-P1 and anti-c
d Since the auto control is positive after the AHG phase and no reactivity was detected at immediate spin, the serology is most consistent with a warm autoantibody. An adsorption with autologous cells to remove the antibody to used the adsorbed plasma for alloantibody detection is the next step.
A 26 yr old female is admitted with anemia of undetermined origin. Blood samples are received with a crossmatch request for 6 units of Red Blood Cells. The patient is group A, Rh-negative and has no history of transfusion or pregnancy. The following results were obtained in pretransfusion testing: IS 37C IAT screening cell I 0 0 3+ screening cell II 0 0 3+ autocontrol 0 0 3+ all 6 donors 0 0 3+ The best way to find compatible blood is to: a. do an antibody identification panel b. use the saline replacement technique c. use the prewarm technique d. perform a warm autoadsorption
b When group specific units of Red Blood Cells are not available, group compatible units are selected. Since the patient is AB, group A would be selected to conserve group O units for group O patients. Rh-negative patients should receive Rh-negative units of red blood cells.
A 29 year old male is hemorrhaging severely. He is AB, Rh-negative. 6 units of blood are required STAT. Of the following types available in the blood bank, which would be most preferable for crossmatch? a. AB, Rh-positive b. A, Rh-negative c. A, Rh-positive d. O, Rh-negative
c Cold agglutinin disease is associated with cold reactive antibodies that typically activate complement. Cells that do not undergo lysis due to complement activation have C3d attached to the red blood cells.
A 56 year old female with cold agglutinin disease has a positive direct antiglobulin test (DAT). When the DAT is repeated using monospecific antiglobulin sera, which of the following is most likely to be detected? a. IgM b. IgG c. C3d d. C4a
c If a patient is negative for clinically significant antibodies, and a single crossmatch is incompatible, the incompatibility is either due to donor cells with a positive DAT or the patient has an antibody to a low-incidence antigen that the donor's cells possess.
A blood specimen types as A, Rh-positive with a negative antibody screen. 6 units of group A, Rh-positive RBCs were crossmatched and 1 unit was incompatible in the antiglobuline phase. The same results was obtained when the test was repeated. Which should be done first? a. repeat the ABO grouping on the incompatible unit using a more sensitive technique b. test a panel of red cells taht possesses low-incidence antigens c. perform a direct antiglobulin test on the donor unit d. obtain a new specimen and repeat the crossmatch
b A positive DAT will interfere with weak D testing causing both the patient and control to demonstrate positive results. Any positive result in the control tube invalidates any results.
A group B, Rh-negative patient has a positive DAT. Which of the following situations would occur? a. all major crossmatches would be incompatible b. the weak D test and control would be positive c. the antibody screening test would be positive d. the forward and reverse ABO groupings would not agree
c The mom does not have the D gene. The father would have to have inherited one gene that produces D and another gene that does not produce D. The mom and dad both passed on genes that do not produce D.
A mother is Rh-negative and the father Rh-positive. Their baby is Rh-negative. It may be concluded that: a. the father is homozygous for D b. the mother is heterozygous for D c. the father is heterozygous for D d. at least 1 of the 3 Rh typings must be incorrect
c Because neonates are immunologically immature, alloimmunization to red cell antigens is very rare during the neonatal period. No crossmatching is required if the initial antibody screen performed with either the baby's or mother's plasma is negative.
A neonate will be transfused for the first time with group O red blood cells. Which of the following is appropriate compatibility testing? a. crossmatch with mother's serum b. crossmatch with baby's serum c. no crossmatch is necessary if initial plasma screening is negative d. no screening or crossmatching is necessary for neonates
a This patient has an anti-A1, which eliminates A1B cells immediately. Rh-negative units should be conserved for Rh-negative patients when Rh-positive units are available. Selection of group B units provides compatible units quickly.
A patient is group A2B, Rh-positive and has an antiglobulin-reacting anti-A1 in his serum. He is in the operating room bleeding profusely and group A2B RBCs are not available. Which of the following blood types is first choice for crossmatching? a. B, Rh-positive b. B, Rh-negative c. A2B, Rh-positive d. O, Rh-negative
a Presence of agglutination at AHG phase with screening cells and 2 out of 6 donor units indicates antibody in patient serum to antigen(s) on screening cells and donor cells. The presence of an autoantibody would most likely react with all cells, including the autologous control or DAT
A patient is typed as group O, Rh-positive and crossmatched with 6 units of blood. At the indirect antiglobulin (IAT) phase of testing, both antibody screening cells and 2 crossmatched units are incompatible. What is the most likely cause of the incompatibility? a. recipient alloantibody b. recipient autoantibody c. donors have a positive DATs d. routeaux
c Initial result was most likely a false negative result due to the omission of patient serum. This would explain the initial negative result followed by the subsequent positive result.
A patient received 2 units of RBCs and had a delayed transfusion reaction. Pretransfusion antibody screening records indicate no agglutination except after the addition of IgG sensitized cells. Repeat tesing of the pretransfusion specimen detected an antibody at the antiglobulin phase. What is the most likely explanation for the original results? a. Red cells were overwashed b. centrifugation time was prolonged c. patient's serum was omitted from the original testing d. antiglobulin reagent was neutralized
a Determining the patient's phenotype allows focusing identification procedures toward antibodies the patient can develop
A patient received 4 units of blood 2 years previously and now has multiple antibodies. He has not been transfused since that time. It would be most helpful: a. phenotype his cells to determine which additional alloantibodies may be produced b. recommend the use of directed donors, which are more likely to be compatible c. use proteolytic enzymes to destroy the "in vitro" activity of some of the antibodies d. freeze the patient's serum to use for antigen typing of compatible units
c Rh antibodies show enhanced reactivity with enzyme pretreated cells. The M and Fya antigens are cleaved from enzyme pretreated cells and therefore there would be no reaction between enzyme pretreated cells and serum containing anti-M or anti-Fya. The incidence of the c antigen is 80% in whites and 96% of blacks. The incidence of the E antigen 29% in whites and 22% in blacks. Increased reactivity with enzyme pretreated cells and incompatible results with 8 of 10 donor units is most likely due to anti-c.
A patient serum reacts with 2 of the 3 antibody screening cells at the AHG phase. 8 of the 10 units crossmatched were incompatible at the AHG phase. All reactions are markedly enhanced by enzymes. These results are most consistent with: a. anti-M b. anti-E c. anti-c d. anti-Fya
a Anti-Fya would not react with enzyme pretreated cells; a select cell panel would allow for individual reactivity of the remaining 2 antibodies. Thiol reagents would be used to disperse agglutination of IgM antibodies; the antibodies in question are IgG.
A patient's serum contains a mixture of antibodies. One of the antibodies is identified as anti-D. Anti-Jka, anti-Fya and possibly another antibody are present. What technique(s) may be helpful to identify the other antibody(ies)? a. enzyme panel; select cell panel b. thiol reagents c. lowering the pH and increasing the incubation time d. using albumin as an enhancement media in combination with selective adsorption
a The reactivity of anti-k and anti-Jsb with enzyme pretreated cells is unchanged and anti-e would show enhanced reactivity with enzyme treated cells. Chido antigens are sensitive to treatment with most enzymes and anti-Ch would therefore not react with enzyme pretreated cells. The Chido antigen is a high incidence antigen.
A patient's serum reacted weakly positive (1+^w) with 16 of 16 O panel cells at the AHG test phase. The autocontrol was negative. Tests with ficin-treated panel cells demonstrated no reactivity at the AHG phase. WHich antibody is most likely responsible for these results? a. anti-Ch b. anti-k c. anti-e d. anti-Jsb
a ZZAP is a reagent that removes IgG from the patient's own cells to allow better adsorption of the IgG autoantibody from the patient's plasma onto the cells. The intent of the autoadsorption is to remove the autoantibody to look for alloantibodies prior to transfusion.
A patient's serum was reactive 2+ in the antiglobulin phase of testing with all cells on a routine panel including their own. Transfusion was performed 6 months previously. The optimal adsorption method to remove the autoantibody is: a. autoadsorption using the patient's ZZAP-treated red cells b. autoadsorption using the patient's LISS-treated red cells c. adsorption using enzyme treated red cells from a normal donor d. adsorption using methyldopa-treated red cells
b The listed criteria are typical for serological calibration of a centrifuge. Optimum spin time is the least amount of time when all criteria are satisfied.
A serological centrifuge is recalibrated for ABO testing after major repairs. Time in seconds 15 20 25 30 is button delineated? yes yes yes yes is supernatant clear? no yes yes yes button easy to resuspend? yes yes yes no strength of reaction? +m 1+ 1+ 1+ Given the data above, the centrifuge time for this machine should be: a. 15 sec b. 20 sec c. 25 sec d. 30 sec
a Antibodies to antigens on cells 2, 3, 4, and 5 can be ruled out in tubes II and III, in which there was no reaction between patient serum and cells
An antibody identification study is performed with the 5 - cell panel shown below: panel cells: Antigens 1 2 3 4 5 Test results: I + 0 0 + + + II 0 0 + 0 + 0 III 0 + + + 0 0 IV + + + 0 0 + auto 0 An antibody against which of the following antigens could not be excluded? a. 1 b. 2 c. 3 d. 4
a In the solid phase technology, the antibody screening cells are bound to the surface of the well. Antibody specific for antigen on the red blood cells attaches, resulting in a diffuse pattern of red blood cells in the well. A negative reaction would have manifested as a pellet of red blood cells in the bottom of the well.
An antibody screen performed using solid phase technology revealed a diffuse layer of red blood cells on the bottom of the well. These results indicate: a. a positive reaction b. a negative reaction c. serum was not added d. red cells have a positive direct antiglobulin test
b Granulocytes must be compatible with the recipient's serum. Granulocyte products have an expiration of 24 hours.
Granulocytes for transfusion should: a. be administered through a microaggregate filter b. be ABO compatible with the recipient's serum c. be infused within 72 hours of collection d. never be transfused to patients with a history of febrile transfusion reactions
b Patients may have antibodies to components of reagents. Washing the patient's cells prior to testing to remove their plasma from the cell suspension will resolve the reactivity with anti-B
In a prenatal workup, the followng results were obtained: Forward group: Reverse group: anti-A anti-B anti-D Rhcontrol A1cells B cells 4+ 2+ 4+ 0 0 3+ ABO discrepancy was thought to be due to an antibody directed against a component of the typing sera. Which test would resolve this discrepancy? a. A1 lectin b. wash patient's RBCs and repeat testing c. anti-A,B and extend incubation of the reverse group d. repeat reverse group using A2 cells
d After washing cells for the DAT or IAT procedure, the AHG should be added immediately and read. Delay can cause a weakened or negative result due to dissociated of the bound IgG in the prolonged time before reagent is added.
In the direct (DAT) and indirect (IAT) antiglobulin tests, false-negative reactions may result if the: a. patient's blood specimen was contaminated with bacteria b. patient's blood specimen was collected into tubes containing silicon gel c. saline used for washing the serum/cell mixture has been stored in glass or metal containers d. addition of AHG is delayed for 40 minutes or more after the serum/cell mixture
d Antiglobulin reagent is used to detect the presence of red cells, coated in vivo with IgG and/or C3d. Antiglobulin reagent may be polyspecific (contains an anti-IgG and anti-C3d) or monospecific (anti-IgG or anti-C3d).
In the direct antiglobulin test, the antiglobulin reagent is used to: a. mediate hemolysis of indicator red blood cells by providing complement b. precipitate anti-erythrocyte antibodies c. measure antibodies in a test serum by fixing complement d. detect preexisting antibodies on erythrocytes
b Lewis antibodies are usually IgM and agglutinate saline suspended cells. Approximately 22% of the population is Le(a+), which would account for 3 out of 10 donor units being incompatible. Anti-P1 is also an antibody that may react at immediate spin, but 79% of the white population and 94% of the black population are P1+. Anti-C and anti-Fya are IgG antibodies that react at the antiglobulin phase.
In the process of identifying an antibody, the technologist observed 2+ reactions with 3 of the 10 cells in a panel after the immediate spin phase. There was no reactivity after incubation at 37C and after the anti-human globulin test phase. The antibody most likely is: a. anti-P1 b. anti-Lea c. anti-C d. anti-Fya
b Agglutination at AHG phase indicates the presence of clinically significant antibody, indicating the need for antibody identification.
Review the following schematic diagram: Patient serum + reagent group "O" cells Incubate --> read for agglutination Wash --> add AHG --> agglutination observed The next step would be to: a. add "check cells" as a confirmatory measure b. identify the cause of the agglutination c. perform an elution technique d. perform a direct antiglobulin test
c Mixed-field reactivity is a characteristic of the A3 subgroup. Transfusion history would be important to be sure it is not 2 cell populations.
Mixed field agglutination encountered in ABO grouping with no history of transfusion would most likely be due to: a. Bombay phenotype (Oh) b. T activation c. A3 red cells d. positive indirect antiglobulin test
c Antibody-antigen complexes are dependent upon a neutral pH. Extremes in pH causes dissociation. Both auto and allo antibodies are recovered in eluates prepared by reagent kits that alter the pH.
One of the most effective methods for the elution of warm autoantibodies from RBCs utilizes: a. 10% sucrose b. LISS c. change in pH d. distilled water
c An ABO discrepancy in an A1 individual, manifested by agglutination in the serum grouping with A2 cells, is most likely due to anti-H. The greatest concentration of H substance is found on O cells, followed by A2 cells. The least amount of H substance is found on A1 and A1B cells.
Refer to the following data: Forward group: Reverse group: anti-A anti-B anti-A1 lectin A1 cells A2 cells B cells 4+ 0 4+ 0 2+ 4+ The ABO discrepancy seen above is most likely due to: a. anti-A1 b. rouleaux c. anti-H d. unexpected IgG antibody
b Reaction with anti-IgG in the DAT and with both screening cells and autocontrol at the AHG phase is indicative of a warm autoantibody.
Refer to the following data: hemoglobin 7.4g/dl ((74 g/L) reticulocyte count 22% Direct antiglobulin test (DAT) Ab screen - IAT polyspecific 3+ SC I: 3+ IgG 3+ SC II: 3+ C3 0 auto: 3+ Which clinical condition is consistent with the lab results shown above? a. cold hemagglutinin disease b. warm autoimmune hemolytic anemia c. penicillin-induced hemolytic anemia d. delayed hemolytic transfusion reaction
a Enzyme treatment would allow for differentiation of the remaining antibodies after rule outs. The Fya antigen would be denatured, allowing determination of whether anti-Jka and -K are present, and to confirm anti-E.
Refer to the following panel: EM Cell D C c E e K Jka Jkb Fya Fyb 37C AHG 1 + + 0 0 + + + + + + 0 2+ 2 + + 0 0 + 0 + 0 + + 0 2+ 3 + 0 + + 0 0 0 + + + 1+ 3+ 4 + + 0 0 + 0 0 + 0 + 0 0 5 0 0 + 0 + 0 + + + + 0 2+ 6 0 0 + + + 0 + 0 + 0 1+ 3+ 7 0 0 + 0 + + 0 + + 0 0 2+ 8 0 0 + 0 + 0 0 + 0 + 0 0 Based on the results of the above panel, which technique would be most helpful in determining antibody specificity? a. Proteolytic enzyme treatment b. urine neutralization c. autoadsorption d. saliva inhibition
a Rh antibodies demonstrate enhanced reactivity with enzyme-pretreated cells. Antibodies in the Kell system do not have enhanced reactivity with enzyme-pretreated cells. Anti-E and -D are ruled out on cell 3 and anti-K is ruled out on cell 7
Refer to the following panel: Enzymes Cell D C c E e K Jka Jkb Lea Leb M N P1 AHG AHG 1 + + 0 0 + + + + 0 + + + + 3+ 4+ 2 + + 0 0 + 0 + 0 0 + + 0 0 3+ 4+ 3 + 0 + + 0 0 + + 0 + + + + 0 0 4 + + + 0 + 0 0 + 0 + + 0 + 2+ 3+ 5 0 0 + 0 + 0 + + 0 + + 0 0 0 0 6 0 0 + + + 0 + 0 + 0 + + 0 0 0 7 0 0 + 0 + + + + + 0 + + + 0 0 8 0 0 + 0 + 0 0 + 0 + 0 + + 0 0 Based on these results, which of the following antibodies is most likely present? a. anti-C b. anti-E c. anti-D d. anti-K
b Reactivity at 37C and AHG indicate the presence of an IgG antibody. Anti-M, although usually IgM, may be partly or wholly IgG. Anti-M is ruled out on cell 4. Anti-Leb is usually IgM and can be ruled out on cells 4 and 8. This leaves anti-E, anti-Fya and anti-K
Refer to the following: EM Cell D C c E e K Jka Jkb Lea Leb M N P1 37C AHG 1 + + 0 0 + + + + 0 + + + + 0 2+ 2 + + 0 0 + 0 + 0 0 + + 0 0 0 3+ 3 + 0 + + 0 0 + + 0 + + + + 1+ 3+ 4 + + + 0 + 0 0 + 0 + + 0 + 0 0 5 0 0 + 0 + 0 + + 0 + + 0 0 0 2+ 6 0 0 + + + 0 + 0 + 0 + + 0 1+ 3+ 7 0 0 + 0 + + + + + 0 + + + 0 2+ 8 0 0 + 0 + 0 0 + 0 + 0 + + 0 0 auto: 0 0 Base on the results of the above panel, the most likely antibodies are: a. anti-M and anti-K b. anti-E, anti-Fya and anti-K c. anti-Jka and anti-M d. anti-E and anti-Leb
b Lack of agglutination between patient serum and with cells that lack one of the high incidence antigens would confirm the specificity of the antibody.
Results of a serum sample tested against a panel of reagent red cells gives presumptive evidence of an alloantibody directed against a high incidence antigen. Further investigation to confirm the specificity should include which of the following? a. serum testing against red cells from random donors b. serum testing against red cells known to lack high incidence antigens c. serum testing against enzyme-treated autologous red cells d. testing of an eluate prepared from the patient's red cells
b Auto-antibody specificity in cold agglutinin syndrome is most often anti-I. This auto-antibody reacts optimally at 4C, but also reacts between 25C and 31C. Autoanti-I can activate complement so C3d can be attached to patient cells. The eluate will be negative as C3d cannot be eluted from cells.
Serological results on an untransfused patient were: antibody screen: negative at AHG direct antiglobulin test: 3+ with anti-C3d eluate: negative These results are most likely due to: a. warm autoimmune hemolytic anemia b. cold agglutinin syndrome c. paroxysmal cold hemoglobinura d. drug induced hemolytic anemia
a Some blood group antibodies, in the presence of their corresponding antigen and complement, activate the complement cascade and demonstrate in-vitro hemolysis.
Some blood group antibodies characteristically hemolyze appropriate red cells in the presence of: a. complement b. anticoagulants c. preservatives d. penicillin
b Second and third generation cephalosporins react when the drug is present in vitro. When serum, drug, and red cells are present, direct or indirect agglutination or lysis may be observed.
The drug cephalosporin can cause a positive direct antiglobulin test with hemolysis by which of the following mechanisms? a. drug-dependent antibodies reacting with drug-treated cells b. drug-dependent antibodies reacting in the presence of a drug c. drug-independent with autoantibody production d. nonimmunologic protein adsorption with positive DAT
c Patients with multiple myeloma demonstrate rouleaux formation, which can cause the appearance of agglutination. If the cells are washed to remove residual plasma, and tests repeated, an accurate red cell typing is obtained. By performing a saline replacement with the reverse typing, true agglutination will remain when the cell buttons of the reverse cells are resuspended in saline.
The following reactions were obtained: Cells tested with: Serum tested with: anti-A anti-B anti-A,B A1 cells B cells 4+ 3+ 4+ 2+ 4+ The technologist washed the patient's cells with saline, and repeated the forward typing. A saline replacement technique was used with the reverse typing. The following results were obtained. Cells tested with: Serum tested with: anti-A anti-B anti-A,B A1 cells B cells 4+ 0 4+ 0 4+ The results are consistent with: a. acquired immunodeficiency disease b. Bruton agammaglobulinemia c. multiple myeloma d. acquired "B" antigen
b Presence of agglutination at AHG phase with both screening cells and autocontrol is indicative of warm autoantibody.
The following results were obtained in pretransfusion testing: 37C IAT screening cell I 0 3+ screening cell II 0 3+ autocontrol 0 3+ The most probable cause of these results is: a. rouleaux b. a warm autoantibody c. a cold autoantibody d. multiple alloantibodies
d Unexpected reactivity with reverse cells should include a test with screen cells at immediate spin to determine if alloantibodies are present. Resolution of the ABO discrepancy can be performed with group B cells that lack the corresponding antigen for the identified alloantibody.
The following results were obtained on a patient's blood sample during routine ABO and Rh testing: cell testing: serum testing: anti-A 0 A1 cells 4+ anti-B 4+ B cells 2+ anti-D 0 autocontrol: 0 Select the course of action to resolve this problem: a. draw a new blood sample from the patient and repeat all test procedures b. test the patient's serum with A2 cells and the patient's red cells with anti-A1 lectin c. repeat the ABO antigen grouping using 3x washed saline-suspended cells d. perform antibody screening procedure at immediate spin using group O cells
d Some subgroups of A are only recognized because of their lack of anti-A in the reverse typing. Often, the donors are confirmed as subgroups of A by an adsorption-elution technique.
The following results were obtained when testing a sample from a 20 year old, first time blood donor: Forward group: Reverse group anti-A anti-B A1 cells B cells 0 0 0 3+ What is the most likely cause of this ABO discrepancy? a. loss of antigen due to disease b. acquired B c. phenotype Oh "Bombay" d. weak subgroup of A
c A serological test to confirm the ABO on all RBC units and Rh on units labeled as Rh-negative must be performed prior to transfusion. Any errors in labeling must be reported to the collection facility
The following test results are noted for a unit of blood labeled group A, Rh-negative: Cells tested with: anti-A anti-B anti-D 4+ 0 3+ What should be done next? a. transfuse as a group A, Rh-negative b. transfuse as a group A, Rh-positive c. notify the collecting facility d. discard the unit
d The major crossmatch tests the recipient's plasma with donor's cells. This would detect any antibody in the recipient that would react with antigens on the donor's RBCs. If a patient were mistyped as a group O rather than group A, then group O cells would be selected for crossmatch and no incompatibility would be found.
The major crossmatch will detect a(n): a. group A patient mistyped as group O b. unexpected red cell antibody in the donor unit c. Rh-negative donor unit mislabeled as Rh-positive d. recipient antibody directed against antigens on the donor red cells
a Detection of antibodies to penicillin requires treatment of test cells with penicillin and the subsequent testing of the patient's plasma and eluate. Test cells that have not been treated with penicillin do not react.
The mechanism that best explains hemolytic anemia due to penicillin is: a. drug-dependent antibodies reacting with drug-treated cells b. drug-dependent antibodies reacting in the presence of drug c. drug-independent with autoantibody production d. nonimmunologic protein adsorption with positive DAT
d An elution is the process of removal of antibody from red blood cells. the product of the elution method is an eluate. The eluate contains the antibody and can be used in antibody identification methods.
The process of separation of antibody from its antigen is known as: a. diffusion b. adsorption c. neutralization d. elution
d The serum of a group O individual contains anti-A, anti-B and anti-A,B. To prepare a suitable reagent, the ABO antibodies must be removed and the anti-D left in the serum. The serum would need to be adsorbed with cells of the A1B, cde/cde phenotype.
The serum of a group O, Cde/Cde donor contains anti-D. In order to prepare a suitable anti-D reagent from this donor's serum, which of the following cells would be suitable for the adsorption? a. group O, cde/cde cells b. group O, Cde/cde cells c. group A2B, CDe/cde cells d. group A1B, cde/cde cells
b Although monoclonal anti-D react with most D+ red blood cells, cells with fewer antigen sites requires testing after the antiglobulin test. The test is referred to as a test for weak D.
The test for weak D is performed by incubating patient's red cells with: a. several different dilutions of anti-D serum b. anti-D serum followed by washing and antiglobulin serum c. anti-D^u serum d. antiglobulin serum
d For neutralization studies to be valid, the saline dilutional control must be reactive. Since neutralization studies involve adding a substance to the patient's plasma, nonreactivity in test tubes may be due to simple dilution. The saline control acts as the dilutional control and must be reactive. When the saline control is reactive, then if the tube with the substance is nonreactive, the interpretation that neutralization has occurred is made. If it is reactive, neutralization did not occur.
To confirm a serum antibody specificity identified as anti-P1, a neutralization study was performed and the following results obtained: P1 + RBCs serum + P1 substance: negative serum + saline: negative What conclusion can be made from these results? a. anti-P1 is confirmed b. anti-P1 is ruled out c. a second antibody is suspected due to the results of the negative control d. anti-P1 cannot be confirmed due to the results of the negative control
b Anti-Leb is confirmed because the tubes with Lewis substance are negative. Nonreactivity of the serum with Le(b+) cells indicates the anti-Leb in the serum was neutralized by the Lewis substance. The test is valid since the patient's serum with saline rather than substance added is still able to react with the Le(b+) cells.
To confirm the specificity of anti-Leb, an inhibition study using Lewis substance was performed with the following results: Le(b+) cells tubes with patient serum + Lewis substance: 0 tubes with patient serum and saline control: + What conclusion can be made from these results? a. a second antibody is suspected due to the positive control b. anti-Leb is confirmed because the tubes with Lewis substance are negative c. anti-Leb is not confirmed because the tubes with Lewis substance are negative d. anti-Leb cannot be confirmed because the saline positive is control
c EDTA chelates calcium preventing blood to clot. This chelation of calcium also will stop the complement cascade. Calcium ions are necessary for C1 to attach to IgG on the red blood cells.
Use of EDTA plasma prevents activation of the classical complement pathway by: a. causing rapid decay of complement components b. chelating Mg++ ions, which prevents the assembly of C6 c. chelating Ca++ ions, which prevents assembly of C1 d. preventing chemotaxis
a In neutralization, a known source of a blood group soluble substance (for example, saliva, urine or plasma) is incubated with a plasma antibody. During the incubation, the antibody combines with the soluble substance. The antibody is neutralized and inhibited from combining with the same blood group substance found on red blood cells when the blood cells are added to the system.
What happens to an antibody in neutralization study when a soluble antigen is added to the test? a. inhibition b. dilution c. complement fixation d. hemolysis
c Samples must be labeled with 2 independent patient identifiers and the date of collection. This information should be identical to that on the patients identification band and request. There must be a mechanism to identify the phlebotomist, but initialing the sample tubes is not required.
What information is essential on patient blood sample labels drawn for compatibility testing? a. biohazard sticker for AIDS patient b. patient's room number c. unique patient medical number d. phlebotomist initials
c A solution of 8% bovine albumin can be prepared by diluting the more concentrated solution with normal saline. The formula to be used is: (vol1 x conc1) = (vol2 x conc2). A solution of 6%-8% albumin is used with some anti-D reagents as a control for spontaneous agglutination.
What is the most appropriate diluent for preparing a solution of 8% bovine albumin for a red cell control reagent? a. deionized water b. distilled water c. normal saline d. Alsever solution
d ABO immunoglobulins develop at approximately 3 months of age, attain adult levels by age 10, and may, but not always, decline in titer in the elderly.
What is the most likely cause of the following ABO discrepancy? Patient's cells vs: Patient's serum vs: anti-A anti-B A1 cells B cells 0 0 0 0 a. recent transfusion with group O blood b. antigen depression due to leukemia c. false - negative cell typing due to rouleaux d. obtained from a heel stick of 2 month old baby
a All 3 antibodies can cause HDFN and delayed transfusion reactions. Anti-Jka is associated with showing dosage
Which characteristics are true of all 3 of the following antibodies: anti-Fya, anti-Jka, and anti-K? a. detected at IAT phase and may cause hemolytic disease of the fetus and newborn (HDFN) and transfusion reactions b. not detected with enzyme treated cells; may cause delayed transfusion reactions c. requires the IAT technique for detection; usually not responsible for causing HDFN d. may show dosage effect; may cause severe hemolytic transfusion reactions
a An anamnestic response is a secondary response from memory cells. There will be an increase in antibody titer upon exposure; the antibody sensitizes incompatible cells circulating in the patient. The DAT appears mixed-field since the patient's own cells are not sensitized.
Which direct antiglobulin test results are associated with an anamnestic antibody response in a recently transfused patient? Test result Polyspecific IgG C3 Control result A +mf +mf 0 0 result B 1+ 0 1+ 0 result C 2+ 2+ 0 0 result D 4+ 4+ 4+ 0 a. result A b. result B c. result C d. result D
b Two reagents used for removing IgG from red blood cells are chloroquine diphosphate (CDP) and EDTA glycine acid (EGA) Using either of these procedures is useful to reduce a patient's DAT and allow phenotyping with IAT reactive antisera.
Which of the followin gis useful for removing IgG from red blood cells with a positive DAT to perform a phenotype? a. bromelin b. chloroquine c. LISS d. DTT
b Rh antibodies show enhanced reactivity with enzyme pretreated cells. Treatment of red cells with enzymes weakens reactivity with antibodies in the MNS and Duffy systems.
Which of the following antigens gives enhanced reactions with its corresponding antibody following treatment of the red cells with proteolytic enzymes? a. Fya b. E c. S d. M
d Most ABO discrepancies are due to problems in the reverse typing. Discrepancies stemming from the forward type or the patient's cells are usually due to Tn activation from a somatic mutation.
Which of the following explains an ABO discrepancy caused by problems with the patient's red blood cells? a. an unexpected antibody b. rouleaux c. agammaglobulinemia d. Tn activation
b Polyagglutination is a property of the cells. Most adult plasma agglutinate the cells due to naturally occurring antibodies directed towards the crypt antigens.
Which of the following is a characteristic of polyagglutinable red cells? a. can be classified by reactivity with Ulex europaeus b. are agglutinated by most adults sera c. are always an acquired condition d. autocontrol is always positive
a Tn is caused from a somatic mutation and the phenomenon is persistent. Resolution of the red cell typing can be performed with enzyme-treated patient cells, since Tn is denatured by enzymes. Although the reactivity with anti-A may be weak, testing with anti-A1 lectin gives strong reactivity, unlike subgroups of A, which are weakly reacting with anti-A and nonreactive with A1 lectin.
Which of the following is characteristic of Tn polyagglutinable red cells? a. if group O, they may appear to have acquired a group A antigen b. they show strong reactions when the cells are enzyme-treated c. they react with Arachis hypogaea lectin d. the polyagglutination is a transient condition
a Adsorption and elution techniques are used to detect ABO antigens that are not detectable by direct agglutination. The cells are incubated with the antibody (anti-A or anti-B) to the antigen expected on the red blood cells. An elution method is performed and the antibody in the eluate is tested for recovering anti-A (or anti-B depending on the specificity that was used in the adsorption).
Which of the following is most helpful to confirm a weak ABO subgroup? a. adsorption-elution b. neutralization c. testing with A1 lectin d. use of anti-A,B
d Reactivity with anti-H is no longer demonstrable, which indicates H substance is present. There is no A or B substance in the saliva as evidenced by the ability of anti-A and anti-B reacting with respective cells. People with H substance and no A or B substance are group O secretors.
Which of the following is the correct interpretation of this saliva neutralization testing? Indicator cells Sample A B O saliva plus anti-A: + 0 0 saliva plus anti-B: 0 + 0 saliva plus anti-H 0 0 0 a. group A secretor b. group B secretor c. group AB secretor d. group O secretor
c Methyldopa is frequently listed as the prototype for drug-independent antibody mechanism where autoantibody is present on the red cells and may also present in the plasma.
Which of the following medications is most likely to cause production of autoantibodies? a. penicillin b. cephalothin c. methyldopa d. tetracycline
a Samples must be labeled with 2 independent patient identifiers and the date of collection. This information should be identical to that on the patient's identification band and request.
Which of the following represents an acceptably identified patient for sample collection and transfusion? a. a handwritten band with patient's name and hospital identification number is affixed to the patient's leg b. the addressographed hospital band is taped to the patient's bed c. an unbanded patient responds positively when his name is called d. the chart transported with the patient contains his armband not yet attached
a The direct antiglobulin test (DAT) is used to identify red blood cells that have been coated with antibody in vivo
Which of the following tests is most commonly used to detect antibodies attached to a patient's red blood cells in vivo? a. direct antiglobulin b. complement fixation c. indirect antiglobulin d. immunofluorescence
d Since crossmatching is a test between the patient's plasma and donor's cells, any incompatibility is due to the donor's red cells. If a patient is negative for clinically significant antibodies to common antigens, an incompatible unit by the antiglobulin test is due to either a positive DAT on the donors red cells or the patient has an antibody to a low- incidence antigen that the donor's cells possess.
Which of the following would most likely be responsible for an incompatible antiglobulin crossmatch? a. recipient's red cells possess a low frequency antigen b. anti-K antibody in donor serum c. recipient's red cells are polyagglutinable d. donor red cells have a positive direct antiglobulin test
d Polyagglutination is a property of the red blood cells. Structures on the red cells are altered due to bacterial enzymes or a somatic mutation, so crypt antigens not normally exposed on cells are now present. Antibodies to the exposed structures are naturally occurring in adult plasma.
Which one of the the following is an indicator of polyagglutination? a. RBCs typing as weak D+ b. presence of red cell autoantibody c. decreased serum bilirubin d. agglutination with normal adult ABO compatible sera
c Rouleaux will readily disperse in saline whereas true agglutination will remain after saline replacement.
While performing an antibody screen, a test reaction is suspected to be rouleaux. A saline replacement test is performed and the reaction remains. What is the best interpretation? a. original reaction of rouleaux is confirmed b. replacement test is invalid and should be repeated c. original reaction was due to true agglutination d. antibody screen is negative
