Machaon Diagnostics, an independent laboratory for testing bleeding and clotting disorders, has launched a same-day genetic testing service for patients prescribed the anticoagulant warfarin.
The company said that it is charging under $200 per test for doctors, hospitals, and clinics that sign up for the service. Once doctors submit patients' blood samples, Machaon's laboratory will test for variations in CYP2C9 and VKORC1 genes. It is estimated that around 40 percent of the general population has at least one of these genetic variations.
"With warfarin being the second most common trigger for emergency room visits, our goal in designing this service was to enable physicians to accurately identify a safe warfarin dose for their patients within a timeframe that was meaningful," Brad Lewis, medical director of Machaon, said in a statement.
Although the FDA has recommended genetic testing for patients being initiated on warfarin and has specified pharmacogenetic-guided dosing ranges in drug labeling, genetic testing in this setting has been slow to take hold. One reason often cited by critics of PGx-guided warfarin dosing is the time — from a few days to up to a week — it takes for physicians to receive testing results for their patients.
"We believe that [Machaon is] the first clinical laboratory in the US to offer this genetic testing service that provides results the 'same-day' a blood specimen is received," Lewis said in a statement.
ParagonDx is another company that offers same-day turnaround for its warfarin PGx test. However, the status of ParagonDx's service is currently uncertain since the FDA recently issued a warning letter to the company, calling two of its analyte-specific reagent probes used to gauge the presence of CYP2C9 and VKORC1 variants "unadulterated" and "misbranded." The FDA has asked ParagonDx to file a pre-market approval application for these probes, which the agency considers to be diagnostic devices (PGx Reporter 04/07/10).
AutoGenomics also offers same-day results. Meanwhile, Kimball Genetics and Harvard Medical School’s testing services, which use Third Wave’s Invader assay, promise to return test results as early as one business day. Other companies have turnaround times ranging from three to seven days (PGx Reporter 10/10/07).
Warfarin, also known as Coumadin, Jantoven or warfarin sodium, is a potent 'blood thinner' or anticoagulant. Machaon's FDA-approved array-based technology detects genetic variations in 2 key genes involved in the metabolism of warfarin.