DETERMINATION OF FETAL RHD STATUS FROM UNCULTURED AMNIOCYTES

Objective: To determine the accuracy of DNA analysis for fetal RhD sta tus using polymerase chain reaction (PCR) on uncultured amniocytes. Me thods: 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 ford b lood obtained at the time of delivery. Results: In 346 of 347 cases (9 9.7%), the PCR results of AF were in agreement with the serologic RhD blood type. The single error was in an RhD-negative fetus (misidentifi ed as RhD-positive) whose AF was contaminated with blood from an RhD-p ositive mother. The likelihood of an erroneous result was 0.3%. Conclu sion: Polymerase chain reaction-based analysis of fetal RhD status usi ng uncultured amniocytes and established primers appears to be highly accurate.