Red blood cell antibody screening with groupamatic system. II. A two-step haemagglutination technique using a trypsin-polybren-citrate method.

The trypsin-polybren-citrate (TPC) technique is based on Lalezari's method and has been developed in the Groupamatic equipment to allow the screening of irregular allo-antibodies which are not detectable on this machine by the present routine techniques. TPC screening has two main advantages: it gives more reliable results for Rh, Kell, Lewis and P antibodies than bromelin-methyl-cellulose, and it permits the screening of Duffy and Kidd antibodies, However, although the TPC technique contributes to an improved quality of the automated screening of blood donor samples, it should not be used as the only method when recipient samples are concerned.

Red cell antibody screening with the Groupamatic system. I. Bromelin methyl-cellulose and saline techniques: evaluation of five years' routine use.

These data comprise 1,231,024 routine tests carried out over a 5-year period on voluntary blood donors. The percentage of positive results on the machines varies from 1 to 3% of the total number of samples tested. Antibodies identified either by manual or automated techniques make up 15--20% of the positive screening reactions. Rhesus, Luewis and P systems prevail, whilst Duffy, Kidd and Ltheran systems are absent. This screening has three main advantages: the supply of plasma for our production of test sera, or therapeutic immunoglobulins; protection of the recipient; partial information on the donor's immunohaematological state, especially for the risk of giving him incompatible blood sometimes in the future.