23 January 2012 - Quest Diagnostics Incorporated (NYSE:DGX), a US-based provider of diagnostics company, said on Friday that the US Food and Drug Administration (FDA) had approved a de novo classification petition to the company's STRATIFY JCV Antibody ELISA testing service.

STRATIFY JCV is the first blood test to receive FDA marketing authorisation for the detection of antibodies to the polyomavirus JC virus (JCV) for stratifying risk for progressive multifocal leukoencephalopathy (PML). PML is a serious brain infection that hits patients with multiple sclerosis (MS) treated with TYSABRI (natalizumab).

STRATIFY JCV was developed as part of an exclusive collaboration between Quest Diagnostics and Biogen Idec (NASDAQ:BIIB), which jointly develops natalizumab with Elan Corporation Plc (NYSE:ELN).