Fetal RHD Genotyping Uses Circulating Cell-Free Fetal DNA

Circulating cell-free fetal DNA (ccff DNA) in maternal plasma from RhD negative mothers was used for noninvasive fetal RHD genotyping.

The SensiGene Fetal RHD genotyping laboratory developed test (RHD genotyping LDT) was evaluated using ccff DNA extracted from maternal blood plasma. Results showed that fetal RHD genotyping can be accurately determined using this test in the first and second trimester of pregnancy.

Utilizing Sequenom's (San Diego, CA, USA) SEQureDx technology, DNA material was extracted from the blood of the mother, enabling direct genetic testing to assess fetal status in the first trimester. This test method is designed to detect ccff DNA from maternal blood and examine multiple regions of the gene that is known to be the most common genetic basis of RhD negative phenotypes.

The study was performed by the Sequenom Center for Molecular Medicine (Sequenom CMM; Grand Rapids, MI, USA) using two cohorts, a first trimester serotype reference group of 207 cases obtained from the Fetal Medicine Foundation (London, England) and a combined first and second trimester genotype reference group of 199 patients. The serotype cohort had a test accuracy of 97.1% (sensitivity of 97.2%; specificity of 96.8%) and the genotype reference cohort had a test accuracy rate of 99.5% (sensitivity of 100.0%; specificity of 98.3%).

Sequenom's wholly-owned subsidiary, Sequenom CMM is a College of American Pathologists (CAP) accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified molecular diagnostics laboratory. The company designs and commercializes laboratory-developed genetic tests for prenatal and ophthalmic conditions. Utilizing the company's technologies, Sequenom CMM provides test results that can be used as tools by clinicians in managing patient care.

The study appears online in the May 31, 2011 edition of Prenatal Diagnosis.

Related Links:
Sequenom
Sequenom Center for Molecular Medicine
Fetal Medicine Foundation