FDA Clears Diagnostic Assay for Group B Strep

By LabMedica International staff writers
Posted on 10 Aug 2018

Image: The NeuMoDx GBS assay is run on the 288 molecular system (Photo courtesy of NeuMoDx Molecular).

Group B Streptococcus (GBS) is a Gram-positive bacterium found in 10% to 35% of healthy adults and is a commonly found bacterium within the human body. A person who carries GBS and does not present symptoms of GBS disease is said to be “colonized” with GBS.

GBS colonization is not considered contagious, however, under certain circumstances, GBS can invade the body and cause serious infection; this is referred to as Group B Streptococcal disease. It is a leading cause of life-threatening bacterial infection in newborns who acquire the disease during birth by vertical (mother-to-baby) transmission. Approximately 2,000 cases of newborn infections occur per year, with estimates of a mortality rate of 0.27 per 1,000 live births.

The US Food and Drug Administration (FDA, Silver Springs, MD, USA) have granted 510(k) clearance to a high-throughput molecular diagnostics platform and Group B Strep assay from NeuMoDx Molecular (Ann Arbor, MI, USA). The 288 Molecular System is an automated sample-to-answer diagnostics platform that runs up to 288 patient samples in continuous random-access mode. The time to first results is approximately one hour, according to the firm, with a walkaway window of more than six hours, and NeuMoDx intends the system to be used in central laboratories of hospitals and clinical reference laboratories.

Testing for GBS colonization is usually performed in the third trimester of pregnancy to prevent complications of transmission to a newborn during labor and delivery. The NeuMoDx GBS Assay is a qualitative polymerase chain reaction (PCR)-based diagnostic test to detect an 88 base-pair region of the pcsB gene and incorporates sample lysis, automated DNA extraction, and real-time PCR. The firm said the assay showed a sensitivity of 97% and specificity of 96% compared to culture in a multicenter clinical performance study.

The revolutionary dry format reagents require no refrigeration and are extremely robust with an on-board stability of greater than 60 days, and ambient temperature storage shelf life of greater than one year. Additionally, the unitized format of the dry reagents significantly increases operating efficiency while minimizing the waste associated with systems requiring manual reconstitution and/or use of bulk format lyophilized reagents.

Related Links:
US Food and Drug Administration
NeuMoDx Molecular