SAN FRANCISCO, April 18, 2012 /PRNewswire/ -- Genetic testing to determine a more accurate initial dosing of warfarin, a drug used to prevent blood clots, remains rare, but is often done for inappropriate patients, according to a new study by Prime Therapeutics (Prime), a leading pharmacy benefit manager (PBM). The study will be presented on Friday, April 20, at the Academy of Managed Care Pharmacy (AMCP)'s 24th Annual Meeting & Expo in San Francisco. The study found that genetic testing associated with warfarin is being performed at a rate of only 4 per 100 individuals, consistent with 2012 American College of Chest Physician guidelines which recommended against routine testing. Despite its rare use, nearly two-thirds of those patients on warfarin who received a genetic test were tested inappropriately, typically those who have already been on the drug for five days or more. "Based on the increased prevalence of genetic testing, it is clear health plans need to ensure the right member is tested at the right time for the best outcomes," said Patrick Gleason, PharmD, director of clinical outcomes assessment at Prime. "Genetic testing for patients taking warfarin remains controversial and this study shows that while testing is rare, a large number of those being tested are not tested appropriately." To identify warfarin genetic testing prevalence, appropriateness and cost, researchers from Prime in collaboration with Blue Cross and Blue Shield of Minnesota (BCBSM), reviewed integrated pharmacy and medical claims data from a 1.2 million member commercially insured population. This study emphasizes the value of health plan and PBM collaboration since combining medical and pharmacy data allows for comprehensive assessment of drug safety, effectiveness and total cost of care that ensures clinical pharmacy decisions reflect a complete view of utilization and costs.