An investigation into the use of activated and non-activated papain in routine rhesus blood grouping.

The activities of three commercial products of papain were compared as supplied and after activation, and when used in the enzyme-serum method for rhesus (D) grouping. Certain dangers in activation became apparent, and accurate determination of the proportions of papain to anti-D appeared more important than indiscriminate activation without reference to the initial enzyme activity. A technique for assessing these proportions is described.