Screening of HBs antigen and detection of corresponding antibodies on groupamatic equipment.

The widespread utilization of Groupamatic equipment for routine immunohaematological tests has increased the demand for serological procedures that can be performed with this machine. We describe the test method which was developed and with which the detection of HBs antigen has now been carried out routinely for 1 year. It is an automated haemagglutination inhibition reaction which is called GIPHA (Groupamatic inhibition of passive haemagglutination). The sensitivity corresponds to 2 CNTS units, the antigen weight for 1 unit being from 1 to 4 ng. The reproducibility is good; the percentage of false positive reactions is about 0.5% and that of technical problems 0.7%. The additional advantages of the machines are numerous, among which we have the possibility of 11 other simultaneous reactions. One of them is the detection of antibodies against HBs antigen, which is a passive haemagglutination test called PHAG (passive haemagglutination on Groupamatic).