The slanted capillary method of rhesus blood-grouping.

In 1944 a method of Rh blood-grouping, using slanted capillary tubes, was described (Chown, 1944). Further experience with the method led to the appreciation of certain errors in it, which, in 1946, we pointed out, together with ways of preventing them (Chown and Lewis, 1946). Although Discombe and Meyer (1948) reported favourably on the revised method, descriptions of the original one remained more readily available in Britain (Mollison, Mourant, and Race, 1948; Pickles, 1949; Poole and Williams, 1951), so that, because of the inherent errors in this form, the method in any form fell into disrepute. We have used the revised method on many thousands of blood samples, and believe that, properly carried out, it is simple, rapid, accurate, and economical for Rh-grouping. The slanted capillary has further advantages and uses which we shall report on later.