ABO Blood Group Testing

What is the FORWARD test detecting for?

You use Anti-A, Anti-B, Anti-AB, and Anti-D

Detects for ANTIGENS on the RBC

What is the REVERSE test detecting for?

You use A1 cells and B cells

Detects for ANTIBODIES in the SERUM

Why would you not do the Reverse testing on an infant under 4 months old?

HAVE NOT DEVLOPED ANTIBODIES

They develop them until 5-6 months

What is an ABO Discrepancy?

When the FORWARD and REVERSE DONT agree

What are the Group 1 Discrepancies associated with?

REVERSE REACTION error, problem detecting ANTIBODIES

Which 3 things may explain Weak or missing antibodies?

BABIES - they dont produce antibodies until a certain age

OLD AGE - DECREASED antibody production

Diseases causing decreased or absent antibodies

What is the BEST WAY to resolve a Group 1 Discrepancy?

Again, associated with missing antibodies/bad reverse

ALWAYS INCUBATE AT ROOM TEMP FOR 30 MIN then centrifuge

What can be done to resolve a Group 1 Discrepancy caused by OLD AGE?

You can either incubate room temp for 30 minutes

ADD MORE SERUM for an elderly patient

What are Group II Discrepancies associated with?

FORWARD REACTION problem

Problem in detecting antigens on the RBC surfaces

What is the main cause for Group II discrepancies?

SUBGROUPS of A and B

remember that there is less antigen found in the subgroups

What is the Acquired B Phenomenon?

E. coli strains can modify the A antigen to react like B ANTIGEN

Which method will resolve the ACQUIRED B Phenomenon?

Acidified anti-B will help with the Acquired B Phenomenon

What are the main ways to resolve Group II Discrepancies?

INCUBATING at room temp for 30 min

What is seen in Group III Discrepancies?

PLASMA Abnormalities, so BOTH forward and reverse are messed up

What is the main formation that causes Group III discrepancies, and false agglutination in the forward and reverse?

Rouleaux

What can Fibrinogen elevation cause in terms of Group III Discrepancies?

PSEUDO CLUMPING of the blood

What are the 2 main ways of resolving Group III Discrepancies?

1. SALINE REPLACEMENT for rouleaux

2. Microscopic examination to determine rouleaux formation

What is Saline replacement for Rouleaux?

Replacing PLASMA with saline, causing Rouleaux to disperse

What is associated with Group IV Discrepancies?

OTHER causes for abnormal ABO reactions

What are 3 examples of Group 4 Discrepancies?

1. Cold temp.

2. Alloantibodies

3. Antibodies to Reagents

What can be done to resolve Group 4 Discrepancies?

PREWARM or use DTT to break stubborn agglutination