Molecular Pathology Laboratory Network

To assist physicians with prescribing warfarin, MPLN offers the Warfarin Sensitivity Test, which detects variations in CYP2C9 and VKORC1 genes.

Despite wide-spread use of warfarin (Coumadin®), treatment management remains difficult because of variable patient response to dosing, the drugs narrow therapeutic window, and the risk for a serious bleeding event. Some variability is due to extrinsic factors such as patient age, height, weight, the effects of drug interaction and initial treatment indications.

Genetic variation in genes CYP2C9 and VKORC1 has also been noted to account for a significant proportion of the remaining variability. Collectively, the combination of extrinsic and genetic factors can account for upwards of 60% of a patient's variability in treatment responsiveness.