WEDNESDAY, Nov. 16, 2016 (HealthDay News) — Circulating cell-free DNA can predict fetal RHD status throughout pregnancy, according to a study published in the December issue of Obstetrics and Gynecology.
Kenneth J. Moise Jr., M.D., from the Baylor College of Medicine in Houston, and colleagues conducted a prospective observational study to assess the accuracy of a new assay to determine fetal RHD status using circulating cell-free DNA. They obtained maternal blood samples in each trimester of pregnancy from 520 non-alloimmunized RhD-negative patients. Using the SensiGENE RHD test, plasma samples were analyzed for circulating cell-free DNA. Using cord blood at birth, neonatal serology for RhD typing was undertaken. Results of the DNA analysis were compared with the neonatal serology.
The researchers found that there were inconclusive results secondary to the presence of the RHD pseudogene or an RHD variant in 5.6, 5.7, and 6.1 percent of samples from the first, second, and third trimesters, respectively. The corresponding false-positive rates for RhD were 1.54, 1.53, and 0.82 percent. Only one false-negative diagnosis was observed, which occurred in the first trimester. This error was found to be due to mislabeling of samples from two patients. Across all three trimesters, the overall test results were in agreement (P > 0.99).
“Circulating cell-free DNA can accurately predict the fetal RhD status in all three trimesters of pregnancy,” the authors write.
One author disclosed financial ties to Sequenom, which manufactures the SensiGENE RHD test and funded the study.
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