ABO Discrepancies Disclosure Objectives Importance Recognition ...
ABO Discrepancies Disclosure Objectives Importance Recognition ...
ABO Discrepancies Disclosure Objectives Importance Recognition ...
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4/12/2011<br />
Forward Grouping Problems<br />
Resolving Additional Antigens<br />
Check clinical history for evidence of colon infections with<br />
Gram negative sepsis<br />
Test an auto control<br />
The patient’s own anti-B will not react with their own AB cells<br />
Acidify the anti-B to a p.H. of 6 and retest<br />
Acquired B antigens will not react in acidified antiserum,<br />
whereas as normal B antigens will react.<br />
Forward Grouping Problems<br />
Spontaneous Agglutination<br />
Result of:<br />
Strong potent cold auto antibodies<br />
Would appear as AB in the front type and O in the reverse type<br />
Strong positive DAT with IgG, C3d and saline control<br />
Wharton’s jelly in cord blood<br />
Forward Grouping Problems<br />
Resolving Spontaneous Agglutination<br />
Incubate plasma and cells (separately) at 37°C for 5 to<br />
15 minutes<br />
▪ Wash cells 5 to 6 times with warm saline<br />
▪ Retest warm washed cells with warm plasma<br />
▪ Retest the DAT and saline control<br />
Treat cells with 0.01M DTT<br />
Wash cord blood a minimum of 6 times with saline<br />
Forward Grouping Problems<br />
Polyagglutination<br />
Result of:<br />
Inheriting acquired abnormalities of the red cell membranes with<br />
exposure to crypt antigens<br />
e.g. T activation.<br />
Bacterially contaminated sample<br />
Resolve by:<br />
Avoid testing with human antisera; use monoclonal antisera.<br />
Collection of a new sample<br />
Reverse Grouping Problems<br />
▪Plasma or serum <strong>ABO</strong> discrepancies are<br />
more common than red cell discrepancies.<br />
Reverse Grouping Problems<br />
Weak/Missing<br />
Additional Antibodies<br />
Rouleaux<br />
5