The US Food and Drug Administration (FDA) has granted a de novo classification petition to Quest Diagnostics' Stratify JCV Antibody ELISA testing service.

The Stratify JCV blood test is designed for the qualitative detection of antibodies to the polyomavirus JC virus (JCV) for stratifying risk for progressive multifocal leukoencephalopathy (PML) in patients with multiple sclerosis (MS) receiving TYSABRI (natalizumab).

Quest’s Stratify JCV FDA market authorization follows a product label change for TYSABRI which will now identify JCV antibody status as a PML risk factor; other risk factors include duration of treatment with TYSABRI and prior immunosuppressant therapy use.

Quest said the Stratify JCV was developed under partnership with Biogen Idec, co-manufacturer with Elan Corporation, of natalizumab.

The test employs technology licensed from Biogen Idec, and is exclusively offered through Quest Diagnostics’ Focus Diagnostics laboratory in the US.