[Observations on antibody determination and differentiation with papain test erythrocytes using the gel centrifugation technique (ID-Microtyping System)].

Background: The gel centrifugation system (ID Microtyping System, Fa. Diamed, Bensheim, FRG) is one of several new methods, which has become commercially available within the last few years for the detection of antibodies against red blood cell antigens.

Materials and methods: During 1 year we used the gel centrifugation method for antibody screening in our routine laboratory by performing 3 tests each time: 1. NaCl card (room temperature) with untreated red cells; 2. NaCl card (37 degrees C) with papain-treated red cells, and 3. Liss-Coombs card (37 degrees C) with untreated red cells.

Results: The two-stage papain test revealed some interesting phenomena: 1. In some cases the sensitivity of the papain gel test is higher than that of all other methods tested in this study, namely in the gel centrifugation technique and in the tube centrifugation technique. 2. There are reactions which seem to be directed against patients' own antigens (in the Rhesus or Kidd system), but there are no positive direct antiglobulin test and no clinical signs of hemolysis. 3. Some sera show reaction patterns which seem to have a distinct specificity, but they cannot be assigned to any of the antigens in the manufacturer's antigenogram.

Conclusions: Before a general recommendation for antibody screening with the two-stage papain test in the gel centrifugation method can be given, further investigations about the clinical value of those antibodies which are detectable only by this technique are necessary. For antibody identification further declarations in the work sheet of the panel would be desirable.