Unformatted text preview: MLS 480 Clinical Immunohematology II Antibody Screen/Antibody ID (Unit 2) Study Guide Objectives
: At the conclusion of this unit, the student will be expected to complete the following objectives with a score of 70% (grade of C) or better on course evaluations. Specifically, the student will be able to: 1. Describe the purpose of the antibody screen 2. Identify the characteristics of screen cells 3. Select appropriate donor units for crossmatch 4. Describe the antibody screen procedure for patients and donor processing 5. Identify the antibodies frequently reacting in specific phases of the IAT, with specific potentiators. Include Rh, MNS, P, Lewis, Kell, Duffy, and Kidd antibodies. Differentiate between IgG and IgM antibodies 6. Interpret results of antibody detection and identification tests 7. Analyze antigen typing in antibody identification protocol 8. Describe the rationale for properly ruling out antibody specificities in identification studies (antigram interpretations). Include the principle of the crossout technique or double elimination 9. State the criteria for conclusive identification of an antibody using the “rule of three” or 3 positives, 3 negatives, or 2 pos 5 neg for 95% probability 10. Compare and contrast the panel characteristics of warm and cold reacting antibodies 11. Evaluate panel results that show dosage 12. Evaluate panel results that indicate the presence of multiple alloantibodies and antibodies to high and low frequency antigens 13.
State the purpose of using cord cells in an antibody identification test 14.
Evaluate panel results that indicate IgM antibodies with a broad thermal range 15. Evaluate the use of an autocontrol Study Guide 1.
Most IgG antibodies are detected in what reaction phase? IgM antibodies in what phase? IgG 37 degrees and AHG phase. with LISS show at AHG IgM IS phase (without wide thermal range) 2.
What is the purpose of a patient autocontrol? To detect autoantibodies (which may interfere with alloantibody search) 3. Briefly describe the composition of antibody screen cells, how an antibody screen is performed and its purpose: What: O type cells, patient serum Procedure: Add Cells and patient serum in tube or gel Purpose: To detect antibodies in the patient serum. 4.
Why is the antibody screen a necessary part of compatibility testing: If a patient has an unknown antibody that is not a normal occurrence. The patient may have a transfusion reaction to donor blood. Antibody panel can be run to assess clinical significance of the antibody. 5.
Discuss the IgG antibodies detected at 37degree phase using albumin as the potentiator: Rh 6. Discuss the IgG antibodies detected at AHG phase using LISS as the potentiator: Kell
Ss Kidd 7. Discuss the IgM antibodies detected at IS phase only: MNP
P MLS 480 Clinical Immunohematology II
Revision 2012 RPaur Antibody Screen / Antibody ID Study Guide Page 1 of 5 Which antibodies are cold agglutinins? M
HI 8. If a patient has broad thermal range IgM antibody where would reactions take place in the antibody screen if LISS was used and antiIgG: IS
37C 9. Why might an IgM not appear at 37 degree phase and only appear in the AHG phase of testing? The IgM antibody needs the priming of the IgG antibodies to the cells and then the IgM antibodies agglutinate the cells. The IgM antibody attached at RT (or colder) and then disassociated from the RBC at 37C. At 37C the test was NEG, but at AHG, polyspecific AHG bound to the complement (that attached at RT/colder). 10. If complement has been activated, what evidence of this would you see in your test tube: Agglutination at the AHG phase Maybe hemolysis because of complement 11.
Evaluate the results. Fill in the blanks from the list provided: IS 37/LISS AHG Check cells Screen cell I 0 0 3+ Screen cell II 0 0 0 √ List the four most likely groups of antibodies in this screen: Rh
Duffy Kidd List the antigens enhanced reactivity by enzymes: Rh
Lewis P List the antigens decreased reactivity by enzymes: MNS Fya & b
Which antigens exhibit dosage: Rh (not D)
Fya & b
Jka & b
MNSs Lua & b
1214. Use the results on Panel A: 12.
Patient G.S. was tested and found to be Group A, Rh positive. He was crossmatched with eight units of A+ blood. One unit of blood as well as the patient’s antibody screen had 3+ agglutination after the AHG. The panel of cells was run showing no agglutination until AHG where only cells 1,2,3,4, and 7 demonstrated 3+ agglutination. All others were negative. Indicate the most probable antibody: AntiK 13. How would you do an antigen typing on the patient? Use specific antiK sera. 14. Is this antibody identification adequate to ensure accuracy of at least 95%? Why or Why not? What else can you do if it is not? Yes, 2 POS, 5 NEG. 1522. Use antigram Panel B: 15.
Patient W.F. was found to be O negative. He was crossmatched with three units of O neg blood. Two of the crossmatched units and the patient’s antibody screen showed weak agglutination after room temperature incubation. No reactivity was observed with the crossmatched units or the antibody screen in the 37C or AHG phases. One panel of cells was set up and incubated at 4 degrees for one hour. A second panel was also done with the same panel kit with the usual IS, 37, AHG and Check cells being done. Indicate the most probable antibody (ies): AntiM 16. Why is the 4degree testing strongest? Cold agglutination MLS 480 Clinical Immunohematology II
Revision 2012 RPaur Antibody Screen / Antibody ID Study Guide Page 2 of 5 17. What does the strength of the reactions tell us: Heterozygous or homozygous. Dosage. 18. Why are there reactions at the AHG phase? The IgG component of antiM are reacting to the complement 19. How do we confirm that this is the most likely antibody? Antigen typing. 20. What would you choose for the donor units? Units free of the antigen AntiM is a cold reacting antibody, so in an emergency you could release the units WITH the antigen. 21. How do you know you are not missing an antibody that appeared at the AHG phase? Run another panel with monospecific AHG 22. Is this antigram conclusive enough to ensure 95% accuracy? Why or why not: Yes, 3 POS, 3 NEG 2326. Use panel C: 23. Patient E.C. tested B positive. One tube of the antibody screen was positive at AHG phase. LISS was used as the potentiator. Panel C illustrates the phases and the reactions. LISS was used as the potentiator. Indicate the most probable antibody (ies): AntiC 24.
How do you confirm the likelihood that you are correct? antigen typing 25. What would you expect if you used albumin as the potentiator and incubated the tubes at 37o
for 30 minutes: AntiC pattern at 37C 26. Is this antigram conclusive enough to ensure 95% accuracy? Why or why not: Yes, 3 POS, 3 NEG 2729. Use Panel D: 27. Patient W.Z. typed O positive. The antibody screen showed one tube positive at AHG phase only. The panel antigram for W.Z. is included. What antibody(ies) do you suspect: AntiFya 28. How do you confirm your suspicion? antigen typing 29. Is this antigram conclusive enough to ensure 95% accuracy? Why or why not: Yes, 3 POS, 3NEG 3033. Use Panel E: 30. Patient E.Z. was found to be A positive. All of the screen cells were positive. What is the most likely antibody(ies): antiJka 31. What are the antibodies you could not rule out? Cw
V N Lua
S 32. Is this antigram conclusive enough to ensure 95% accuracy? Why or why not: MLS 480 Clinical Immunohematology II
Revision 2012 RPaur Antibody Screen / Antibody ID Study Guide Page 3 of 5 No, only 2 cell lines NEG. 33. What can you do if it is not? Find more cells from 1120 that are Jka
NEG 34. A prenatal patient specimen with a positive antibody screen test has been found. How would you proceed: Perform an antibody panel. Perform titer 35. Identify the following characteristics for the antibodies listed: What phase of testing each appear in (IS, 37(LISS), AHG) and whether they are predominately IgM or IgG. Ab Phase IgM/IgG Ab Phase IgM/IgG antiE AHG G antiJk(a) AHG G antic AHG G antiH IS M antie AHG G antiC AHG G antiP IS M antis AHG G a
antiK AHG G antiFy AHG G antik AHG G antiM IS M 34. What are antibody screen cells: Type O cells with common antigens 35. Of the antibody identification panels AE do any of the antibodies show dosage: antiM
D 36. If you suspected a second antibody may also be hidden on an antibody identification panel, how would you have suspected this and how would you pursue the hunt: Strength of reactions. Units without antigen are still not compatible. Test more lines without first antigen, but WITH the suspected second antigen. 37. Discuss the different probability for meeting 95 predictability other than the 3 pos and 3 neg cell lines for antibody confirmation. 2 POS, 5 NEG 1 POS, 19 NEG 38. Discuss how dosage would appear in the reaction phase of an antibody identification panel. A stronger reaction from a homozygous situation, versus a weaker reaction from a heterozygous reaction. 39. How can you determine if the patient has an unexpected broad thermal range IgM antibody when you are doing gel testing in transfusion services? 40. What information would you gain adding cord cells to an antibody identification panel? Differentiate between antiD and antiLW AntiI would not react and Antii would react 41. In tube testing how can you distinguish between warm and cold reacting antibodies? Cold antibodies react in the IS phase. Warm antibodies will react at 37 C or AHG phase or both 44.
In what phases would a broad thermal range IgM likely appear using LISS as the potentiator and antiIgG only as the AHG reagent? MLS 480 Clinical Immunohematology II
Revision 2012 RPaur Antibody Screen / Antibody ID Study Guide Page 4 of 5 I
S 37 AHG +
In what phases would a broad thermal range IgM likely appear using PEG as the potentiator and polyspecific AHG? IS 37 AHG +
In what phases would a broad thermal range IgM likely appear using LISS as the potentiator and polyspecific AHG reagent? IS 37 AHG +
+ MLS 480 Clinical Immunohematology II
Revision 2012 RPaur Antibody Screen / Antibody ID Study Guide Page 5 of 5 ...
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- Summer '16
- Not Sure
- Biology, AHG, antibody screen, Duffy Kidd