While 80% of persons possessing blood group A are of group A1, 6 other subgroups of A substance may occur.
(1) unexpected anti-A activity (mismatch between front and back typings)
(2) weak or absent reaction with antisera
Method for evaluation:
(1) reaction of cells with specific antisera or with lectins having an activity mimicing an antisera
(2) reaction of sera with cells of known phenotype
(3) if the person is a secretor, the presence or absence of A substance in the saliva
2+ mixed field
• anti-A1 or lectin Dolichos diblorus
• anti-H or lectin Eulex europaeus
• A1 cells
0 to 4+
• A2 cells
• B cells
• O cells
A substance in saliva of secretors?
• anti-A1 may be present in 1-8% of patients with type A2 and 22-35% with type A2B.
• anti-A1 may rarely be found in patients with type A3 or A3B
• A person with type AB would show a reaction between cells and anti-B, while anti-B would not be in the sera.
0 to +/-
1+ to 2+
0 to 2+
0 to 1+
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Specialty: Clinical Laboratory