A modification of Hepatest, using the Terasaki plate, for the detection of HBSAg in blood donors.

A simple modification of Hepatest (Wellcome Reagents) is described, which lends itself to the rapid large-scale screening of blood donors. The technique uses 4 mul of HBSAb coated turkey cells (Cayzer et al., 1974), and Terasaki plates (Hopkins and Das, 1973), in contrast to the 25 mul used in the microtitre tray technique. This results in a considerable saving on the cost of reagents, the cost per test being reduced to 16% of the cost of the recommended method. In our hands, this modification is as convenient to use as the manual microtitre tray technique. Positive sera from the screen test are also tested for non-specificity using horse IgG coated turkey control cells. The falso positive screen test rate has been reduced by the adoption of a modified buffer containing turkey serum.