Download MLS UAMS Bloodbank Case Study Test 2 | 100% Correct Answers | Verified | Latest 2024 Versi and more Exams Immunology in PDF only on Docsity!
MLS UAMS Bloodbank Case Study Test 2 |
100% Correct Answers | Verified | Latest
2024 Version
What is Poly-specific AHG - ✔✔Antibody to IgG and complement What is Mono-specific AHG? - ✔✔Antibody only to IgG or complement only What are the conditions for which the DAT is most often performed? - ✔✔
- Hemolytic disease of the newborn
- Drug reactions
- Autoimmune hemolyitc anemia
- Transfusion reaction What can be deduced from a negative IAT? - ✔✔
- Antibody is present but is too weak to react
- Antigen to the corresponding antibody is not present on the screen cells
- No antibody present in the patients serum List the criteria which must be met before it is acceptable to perform only an IS crossmatch? - ✔✔
- Negative IAT
- No previous history of an antibody
- No typing discrepancies or any other serological inconsistencies Which of the following must be rejected as the sample for ABO/Rh typing and pretransfusion testing A. red top clotted tube B. EDTA tube C. Red top tube with added thrombin
D. SST (Serum separator) tube with gel - ✔✔SST (Serum separator) tube with gel You are using commercial antisera to antigen type units, and need a panel cell to use as a positive control. Do you want a cell which is homozygous or heterozygous for the antigen in question? Why? - ✔✔It is better to use heterozygous one for the antigen to make sure the antisera will detect a weak antigen Why is it necessary to identify an antibody if compatible blood is found via the crossmatch? - ✔✔The antibody must be identified so the units (even if crossedmatch is negative) can be phenotyped and found lacking the antigen What is the most common reason that ABO incompatible blood is transfused to someone? - ✔✔Clerical or Patient ID error True or false: Although the crossmatch is the most reliable pre-transfusion test, it does not detect Rh typing errors, all clerical errors, or extremely low titer antibodies. - ✔✔True True or false: If all crossmatch tubes are agglutinated, the units are considered compatible and units can be transfused to the patient. - ✔✔Fase, all the tubes must NOT agglutinate for them to be compatible True or fasle: A hemolyzed specimen is acceptable for crossmatching. - ✔✔False, hemolysis is a sign of a reaction and is considered incompatible, so a hemolyzed sample would give a false positive True or false: All Panel cells are group O negative cells - ✔✔False, some of them are O+ True or False: If the auto control is positive in the antiglobulin phase of the antibody test, a DAT should be performed - ✔✔True True or False: In the indirect antiglobulin tests (IAT), serum contains the antigen. - ✔✔False, serum contains the antibody. Red cells contain the antigen. True or False: Inadequate washing of red cells in the IAT will leave patient's plasma containing protein around the red cells resulting in neutralization of the AHG - ✔✔True
- Washes red cells to remove free serum immunoglobulins
- Positive in baby with ABO HDN How could you make check cells? How should you proceed if they do not give agglutination on a negative IAT or DAT? - ✔✔Check cells are D+; If it does not agglutinate, then you need to repeat the whole test What are screening cells? What ABO type do they need to be. Why? - ✔✔Screening cells are Group O cells from individuals who have been phenotyped for all clinically significant antigen; It must be O because ABO antibodies in patient serum does not interfere. How often must a new sample be drawn for compatibility testing and why? - ✔✔It needs to be drawn every 3 days to ensure the current immunologic status Would you rather find an anti K or an anti e in a patient needing blood when you are alone in the lab at midnight? Why? - ✔✔Would rather find an ANTI-K, because 91% of type specific units would be compatible. Only 2% of type units for little "e" (most people have the antigen for little "e" Define high frequency and low frequency antigens and give an example of each - ✔✔High frequency, example: most people have the antigen Lutheran B, 99% of the population. Low frequency, most people lack the antigen, example: Diego a 1% of population Explain how someone could have an antibody on his/her cells but not in the serum? - ✔✔This occurs with autos- all the antibody could be attached to the red cells, leaving little or none in the serum Why is patient history important when performing a DAT? - ✔✔To know the transfusion and drug history to properly interpret the results What is best sample for a DAT? Why? - ✔✔EDTA, Plasma chelates calcium; Without calcium no in vitro complement can be activated so the results reflect in vivo complement activation What would give a false + on an IAT? - ✔✔Poly/autoagglutinable cells Saline cotaminated with bacteria or other substances Failure to add LISS
What would give a false = on an IAT? - ✔✔Too weak cell suspension Inadequate washing Failure to centrifuge Contamination of AHG with serum Dirty Glassware Demonstrates dosage: - ✔✔Anti MN, Kidd (Jka and Jkb) Duffy (Fya and Fyb) and Rh Antibodies which can be neutralized: - ✔✔Lewis a and b and P Enzyme treated panel: - ✔✔Enhances antibodies to Rh and Kidd Destroys antibodies to MNSs and Duffy a and b If a patient is O and has a negative screening test, and was crossed matched with 2 units and 1 of the units had a 1+ reaction, what 2 reasons could there be for the positive reaction? - ✔✔1. Donor cells have a + DAT
- the patient has an antibody to low incidence antigen not on any screening cells An eluate was performed on the donor and it reacted with all panel cells. Explain. - ✔✔This shows that the coating of the cells is not an specific antibody but it is a warm auto What should be done with the unit which was incompatible, if it is due to the donor having a positive DAT? - ✔✔Since it will be incompatible with all cells, it should be discarded Besides drug induced coating of cells, what are the other three conditions for which a DAT is performed?
- AIHA
- Transfusion reaction Antibodies in AIHA are often associated with which blood group system? - ✔✔Rh system, if they have any specificity
Eluate reacts with A and B Can be seen on 1st pregancy Mom needs RhIG (depends) Caused by IgG antibodies Lui freeze elution Anti-D HDN - ✔✔Most serious Mom always Rh= DAT Strong+ Run spectral scan Mom's IAT+ Baby often needs exchange transfusion Type of elution procedure used Kleihauer-Betke stain is not reliable if: - ✔✔Mom has elevated Hgb F from Thalassemia or HPFH Mother Brown, who is group O Rh negative delivers her baby and a cord blood sample is sent to Blood Bank. The cord cells do not react with anti A, anti B, anti A,B nor anti D. The DAT is a 2+. Select the best course of action: - ✔✔Perform a Elu II (digitonin elution) Why must neonatal red cells be washed numerous times? - ✔✔To remove the Wharton Jelly List the typical tests performed on a baby who has suspected HDN? - ✔✔ABO, Rh, DAT Elution if DAT +, Bilirubin. Prior to birth: May be spectral scan, amniocentesis, Anti D titer on mom, L/S ration, PUBS Which tests are performed on the mom at the beginning of the pregnancy? At birth, if the baby has suspected HDN? - ✔✔Pregnancy- ABO, Rh, (this includes a weak D) Birth- ABO, Rh, IAT, Fetal screen if she is Rh = Baby has + DAT. Mom is O + and has = IAT. What is next step to determine the cause of + DAT? - ✔✔Elution and combine the eluate with A ng, O, neg B neg and O pos cells
Would you expect a B + mom with an anti Lea to have a baby with HDN. Why or why not? - ✔✔No. Lewis A does not cross the placenta. No ABO HDN because she is B, No Rh HDN because she is Rh+ When an OB patient has Lewis antibody, why is it not necessary to perform a titer? - ✔✔Lewis A does not cross the placenta Mom is O= with anti D titer of 1:256. Baby types as O= with a 3 + DAT. What is causing the DAT and how would you prove this. Which, if any of these results are probably spurious? - ✔✔Baby is probably Rh +. The baby types as D = because cell D Antigen sites are coated by mom's high titer anti D. This baby needs the Anti D eluted off cells. If eluate is Anti D, this proves baby is D+ The ABORh has 4+ anti-A, = Anti-B, 2+ A cells, 4+ B cells.The screening cells are positive at the IS stage but neg at 37 degree and AHG, what is the probable cause of the positive screening and typing discrepancy? - ✔✔Cold Auto How could a cold auto be confirmed which antibody is in the serum? - ✔✔Test with mini cold panel - if positivie will all but cord cells, is anti I If a cold auto is present, how could other antibodies be detected? - ✔✔Prewarmed IAT or auto absorption What should be done to any blood product prior to transfusion if there is a Cold auto? - ✔✔Prewarm the blood product What would a patient DAT be if it was a Cold auto? - ✔✔Polyspecific + Anti IgG = Anti-C3 + What would a patient DAT be if it was a Warm auto? - ✔✔Polyspecific + Anti- IgG + Anti-C3 = What is coating the cells with a cold auto in the DAT? - ✔✔Complement
