Erythrocytic Antigenic Determinants Characteristic of H, I in the Presence of H [IH], or H in the Absence of i [H(‐i)]*

Homologous agglutinins demonstrated to require the simultaneous presence on erythrocytes of I and H appear to be the same as those previously called “anti‐O” or “non‐inhibitable anti‐H”. These have been termed anti‐IH. In addition, hemagglutinins with similar specificity but which are readily inhibited by soluble H substances have been termed anti‐H(‐i). Implications in regard to known problems in the typing of cord blood red cells have been mentioned.