Question

brerence lab received a blood sample for testing that unfortunately arrives before the patient's paperwork including medical history. The bloodworks year old male with the following results: aing medical history. The bloodwork is on a 29 Anti-A Anti-B 2+mf A: Cells 3+ B Cells 0 What is your hypothesis regarding the results (i.e. what is the patient's blood type) and what additional testing (along with expected results would you perform to confirm your prediction? 5. You receive a patient's sample for a blood typing confirmation. The patient receives transfusions about 3-4x per year to treat a chronic condition, and is type A. The patient has always given the expected forward and reverse typing previously, however today you receive the following results using your automated analyzer. Anti-B B Cells Anti-A 4+ A: Cells 3+ 0 After ruling out a clinical error, you perform additional testing as follows: Type O Cells: 0 A1 Cells at 37°C: 3+ A2 Cells: 0 A. Lectin: 4+ Your lead tech assists your investigation and performs reverse typing with a different lot of reagent cells. Her results are: A: Cells B Cells O Cells Az Cells 4 + 3+ 0 0 How do you explain these results?

Answer 1

Thirty three blood group systems have been discoverd and the number keeps increasing. Among these ABO grouping system is the most important one. In this system Antigens A and B are present on the RBC surface and antibodies A (Anti A), Antibodies B (Anti B) are present in the serum. Thus four blood groups namely A, B, AB, O can happen in any individual.

The table below will help you in understanding the same

BLOOD GROUP	Antigen (RBC surface)	Antibody (In Serum)
A	A	Anti B
B	B	Anti A
AB	AB	No Antibodies
O	No Antigens	AB

In the above case patient has no agglutination with anti A so patient does not have A antigen on surface. With Antibody B it is weak agglutination. So must be having some B Antigen on surface. However reverse grouping no B antigen is detected (B-0). Hence Patient must be having one of the subtypes of B blood group. probably B3, because of 2+ with anti B. Other subtypes like Bm and Bx would not show any reaction with anti B.

History is very important.  Ask about previous transfusion, does the patient has a twin, Any Bone marrow transplantation etc

The other investigations that can be done are:1. Repeat Blood Grouping again - Forward grouping using anti A, anti B, anti A1B and Reverse grouping using A1 cells, A2 cells, B cells, O cells, lectin test with anti H, Saliva test and adsorption elution test.

Genetic testing of blood group Type using Polymerase chain reaction and Restriction Freagment Length Polymorphism can confirm the same

5. Here patient has a chronic disease and has had multiple transfusions. But he is a known A blood group. So he has A antigen on his RBC and Antibodies in serum.

Hence Anti A is 4+ - confirms presence of Antigen A

Anti B is 0 - No Antigen B

A1 Cells is 3+ - Patient serum is not supposed to cross react with Antigen A1 as the seum is not supposed to have any antibodies to A antigen

B cells is 4+ - means patients serum has antibodies against B antigen

Conclusion is Patient has Antigen A, Antibodies against both A1 and B group which is not Possible and should not happen

Second time additional testing also confirms the presence of antibodies against A 1 Antigens

Third time testing no antibodies against A1 is found in the serum of the patient as confirmed by reverse grouping using A1 cells.

B1 Cells are positive - B antibodies in serum

O cells are positive due to anti h antibodies in serum

This patient must have acquired warm Antibodies against A1 antigen (hence reaction at 37 degree body temperature) due to multiple transfusions that was removed during processing of blood for reverse grouping