[On the ABO character of human hair (author's transl)]

Typing results of 346 hair samples from 195 donors by a modification of the absorption-elution test are reported. Antihuman globulin serum was added at the end of the usual procedure. In this way, agglutinations increased in strength, while negative reactions were not influenced. In the coure of this investigation, other steps of the method were modified tentatively. The least erros were noted by analysing hairs from the neck (instead of the crown region), by the use of high-titered anti-A, B(O) serum and of unwashed red-cell suspensions, by addition of undiluted Coombs serum and reading of the results after 24h. Nevertheless, the rate of errors remained at 20% which is still too much. Also, a systematic and reproducible error may occur which causes results differing from the red-cell type and is comparable to the phenomenon of aberrant secretors.