Determination of fetal RhD status from uncultured amniocytes.

OBJECTIVE

To determine the accuracy of DNA analysis for fetal RhD status using polymerase chain reaction (PCR) on uncultured amniocytes.

METHODS

Three hundred forty-seven amniotic fluid (AF) samples obtained for a variety of clinical indications were tested for fetal RhD status using PCR and primers specific for the genes coding for D and Cc/Ee. Fetal RhD status was confirmed by serologic methods on neonatal cord blood obtained at the time of delivery.

RESULTS

In 346 of 347 cases (99.7%), the PCR results of AF were in agreement with the serologic RhD blood type. The single error was in an RhD-negative fetus (misidentified as RhD-positive) whose AF was contaminated with blood from an RhD-positive mother. The likelihood of an erroneous result was 0.3%.

CONCLUSION

Polymerase chain reaction-based analysis of fetal RhD status using uncultured amniocytes and established primers appears to be highly accurate.