Assessment of QF-PCR as the first approach in prenatal diagnosis

Abstract

Quantitative fluorescent PCR (QF-PCR) has been used by many laboratories for prenatal diagnosis of the most common aneuploidies. QF-PCR is rapid, cost-effective, and suitable for automation and can detect most abnormalities diagnosed by conventional karyotyping. Whether QF-PCR should be used alone in most of the samples and in which karyotyping should also be offered is currently a topic of debate. We evaluated and compared the results obtained from 7679 prenatal samples in which conventional karyotype and QF-PCR had been performed, including 1243 chorionic villi and 6436 amniotic fluid samples. Concordant QF-PCR and karyotype results were obtained in 98.75% of the samples. An abnormal karyotype associated with adverse clinical outcome undetected by QF-PCR was found in 0.05% of samples. Therefore, QF-PCR can be used alone in a large number of samples studied in a prenatal laboratory, thereby reducing both the workload in cytogenetic laboratories and parental anxiety when awaiting results.

Figure 1

Flow chart to evaluate prenatal diagnosis results. Number of samples are in parentheses. The suggested protocol is shown in the gray upper area, and the results obtained in the present study are summarized below. Light gray boxes include discordant results that could affect pregnancy management. Dark gray boxes indicate discordant results that would be missed if the proposed protocol had been followed. Note that 0.07% of cases with different clinical management would be missed following the proposed protocol.