The evaluation of maternal anti-D concentrations during pregnancy.

Anti-D quantitation by the AutoAnalyzer technique has been shown to be a helpful aid in assessing the severity of D alloimmunization during pregnancy. In this study, the technique has been used both to detect antibody boosting after amniocentesis and to differentiate active D immunization from the presence of passive antibodies. The AutoAnalyzer technique and the more generally used indirect antiglobulin test titration method showed good agreement at titre levels of 32 or lower. A titre of 32 was found to be a good discriminative level to separate the mildly affected from the more severely affected newborns suffering from Rh haemolytic disease. At higher titre levels, however, the AutoAnalyzer technique was the method of choice for correct clinical assessment of the severity of D alloimmunization.