Fig. 1

Differences in mean reaction strength of polyclonal antisera (anti-Fy^a, anti-Fy^b and anti-s) when titrated using doubling dilutions. Reactions represented on a 0–4 haemagglutination scale. Differences are shown between (a) Immulab 0.8% Abtectcell III and Bio-Rad 0.8% ID-DiaCell I-II-III when tested in Bio-Rad polyclonal AHG CAT (b) Immulab 0.8% Abtectcell III and Grifols Perfect Screen 3 when tested in Grifols polyclonal AHG CAT and (c) Immulab 0.8% Abtectcell III and Ortho Diagnostics 0.8% Surgiscreen when tested in Ortho BioVue polyclonal AHG CAT