Flow cytometric quantitation of serum anti-D in pregnancy.

BACKGROUND

The major cause of fetal hemolytic disease is maternal immunization to D in D-incompatible pregnancies. To prevent complications, D-incompatible pregnancies are monitored for the level of maternal anti-D. At present, the monitoring of anti-D levels is performed by the indirect antiglobulin test complemented by quantitation by the technique used in an automated antibody detection and quantitation instrument.

STUDY DESIGN AND METHODS

Flow cytometry was used to quantitatively determine the level of anti-D in serum and to analyze the IgG subclass distribution and the presence of IgM anti-D in these samples. The results were compared to the indirect antiglobulin test titer and to the results obtained by the technique used in an automated antibody detection and quantitation instrument.

RESULTS

Flow cytometry allowed sensitive and accurate determinations of anti-D levels with low interassay and intra-assay variability, both for serum samples and standard curves.

CONCLUSION

Flow cytometry is a simple, rapid, and reliable method for determining the serum levels of D antibodies and their Ig subclass distribution. It is therefore well suited for the monitoring of women during D-incompatible pregnancies.