Chido‐Substance in Plasma

Abstract

Abstract. The specific inhibition of anti‐Chido by the plasma (and serum) of Chidopositive subjects (adult and newborn) is the basis for the Chido‐substance inhibition test. This test has proved to be a reliable method for detecting Chido‐negative donors, and for identifying anti‐Chido. Among 639 random donors in Toronto, the plasma of 11 lacked Chido‐substance (i.e., 1.7% were Chido‐negative). The Chido‐antigen in human plasma is thus a useful genetic marker.