When anti-A serum is mixed on a slide with an equal volume of a suspension of A1, A2 and A2B cells with a volume fraction of 0,05 to 0,1, agglutination of each suspension should first appear in not more than twice the time taken when the same test is performed with the reconstituted but undiluted International Standard Preparation of anti-A blood-grouping serum or with a reference standard of equivalent avidity.
Kadar serum anti-A na stekleni ploščici zmešamo z enakim volumnom suspenzije celic A1, A2 in A2B z volumensko frakcijo od 0,05 do 0,1, se mora aglutinacija pojaviti v največ dvakratnem času, ki je potreben za izvedbo enakega testa na rekonstituiranem, vendar nerazredčenem mednarodnem standardnem pripravku seruma anti-A za določanje krvnih skupin ali z referenčnim standardom z enakovredno avidnostjo.