Description

This test is most often performed on the plasma of pregnant women which contains an antibody(ies) implicated in causing Hemolytic Disease of the fetus and newborn (HDFN).Serial, two-fold dilutions of serum are tested against red cells carrying the antigen of interest (e.g., D, K) using the indirect antiglobulin method. Result is expressed as the reciprocal of the highest serum dilution which still shows (1+) agglutination. This test is used to monitor serum alloantibody levels in previously sensitized pregnant women for prenatal management of hemolytic disease of the newborn (HDN).Testing may be repeated at intervals throughout the pregnancy to monitor for a significant increase in titer.  In women with Rh alloimmunization, anti-D levels greater or equal to 16 are generally considered an indication for invasive fetal testing.