Mercaptoethanol‐Stable Antibody Test Predicting Hemolytic Disease of the Newborn Due to ABO Incompatibility

Maternal sera were titrated after 2‐mercaptoethanol treatment for anti‐A and anti‐B agglutinations by the saline and the anti‐globulin methods; the results were expressed in titration scores. Each case was graded into mercaptoethanol‐stable antibody (MESA) grade 1: A and B mothers with compatible infants; 2: mothers with unaffected incompatible infants; 3: mothers with mild hemolytic disease of the infant, and 4: mothers with severe hemolytic disease of the infant. 925 cases were submitted for the ABO incompatibility tests in 2 years; the babies' sequelae were reported in 131 ABO‐incompatible cases. If the tests were done in late pregnancy, severe cases of hemolytic disease of the newborn corresponded to mothers' antenatal antibodies in MESA grade 4, and mild cases to MESA grade 3.