Question

Blood Bank Case1

Bill, a 50-year old man, was admitted to the ER after a serious car accident. He needed emergency surgery for abdominal injuries. His physician ordered a type and crossmatch for 6 U. The results are below in table BB-1.

Table BB-1

Forward Grouping			Reverse Grouping		Rh Testing
	Anti-A	Anti-B	A Cells	B cells	Anti-D	D Control
Brett F.	0	0	4+	4+	3+	0

Antibody Screen

Screening Cell I

Screening Cell II

Screening Cell III

Autocontrol

IS

37

AHG

CC

IS

37

AHG

CC

IS

37

AHG

CC

IS

37

AHG

CC

Brett F.

0

1+

4+

0

2+

3+

0

0

0

3+

0

0

0

4+

Questions

1. What is Bill blood type?
2. What is your interpretation of the antibody screen?

3. What immunoglobulin class is/are the antibody(ies)? Explain.

Review figure of antibody panel at the end of this case study. In this case study, antibodies are excluded only if the patient’s serum does not react with panel cells that are homozygous for the antigen

4. What antibody(ies) cannot be ruled out by the panel results?

5. Is any antibody in question 3 a perfect match for the panel results?

6. What are some (3) possible explanations for the panel results?

7. What is the most likely explanation for the panel results?

8. What is/are the most likely antibody(ies)?

9. What three confirmatory procedures are used to confirm antibody identification?

10. How would you rule out the remaining antibodies?
11. Explain how the technologist would proceed to find compatible units for crossmatch.

12. Questions:

1. Approximately what percentage of units would be compatible?
2. how many units would have to be phenotyped to find 5 compatible units?

Answer 1

Bill blood group is AB positive .

Patient serum before Transfusion to make sure that he has no unexpected antibodies to react with donor cells . In this case, we do not want the recipient's antibodies to attach to the donor cells,causing a transfusion reaction.

IgG antibodies, most of which are considered clinically significant and capable of causing Hemolytic Transfusion Reactions.

Screening cells are cells from2 or 3 individual donors.The most common clinically significant antigens as possible be homozygous on the red cells because a double dose of the Ag results in stronger reactions and therefore can detect weaker Antibodies.

Procedure for Ab Screening / Cross - Match Techniques :-

Phase(1)

Immediate Spin - to check whether the reaction is due to an IgM An instead of IgG or complement activation

Phase (2)

37 degree Celsius Incubation - Is required since IgG clinically significant antibodies are warm acting antibodies.Can add enhancement media if desired ( LISS or albumin).

Phase (3)

Coimbatore Phase ( AHG or AGT ) - Is required since a number of these clinically significant antibodies may only show up at this phase.

After the procedure ,if there is

A) No agglutination or hemolysis : Compatible

B) Agglutination or hemolysis seen : Incompatible

2- 5% red cell suspension.

Importance of Ab screening :-

a) Detect as many clinically significant antibodies as possible.

b) Minimize detection of nuisance antibodies.

c) Prompt delivery of blood to patient.