PT/INR: The Case for Point-of-Care Testing

Every year, two million new people begin taking warfarin, an oral anticoagulant drug that helps to prevent blood clots, heart attacks and strokes. The drug's optimal dose can be tricky to set from person to person and depends on many risk factors, including age, diet and the use of other medications. Studies have shown that one-third of people receiving warfarin metabolize it differently than expected.¹

If too high a dose of warfarin is given, the resident is at risk of life-threatening bleeding. On the other hand, if too low a dose of the drug is administered, they are at risk of equally dangerous blood clots.¹ To monitor how well the drug is working, physicians and caregivers must perform prothrombin time, or PT, tests to evaluate the blood's ability to clot properly. The results of the PT test are then compared to the expected value in healthy people, known as the International Normalized Ratio, or INR.

Until fairly recently, caregivers had to send blood drawn for PT/INR testing to a lab for analysis, which takes precious time. However, with the introduction of units designed for point-of-care testing, healthcare personnel can now receive PT results quickly, allowing them to arrange for faster warfarin dosage adjustments and potentially avoid life-threatening complications.

Point-of-care PT/INR testing is possible because it has received CLIA-waived status, which is granted to tests that have low complexity, low risk for incorrect results and will not harm the resident if performed incorrectly. These tests are typically easy to perform and do not require special training or education.²

Professional Medical now offers the only point of care device that uses direct detection of clot formation to test rather than an electrochemical process. The portable Coag-Sense PT/INR system provides accurate results in less than a minute and requires a small blood sample size.

References
1 Food and Drug Administration. FDA Approves Updated Warfarin (Coumadin) Prescribing Information. Available at: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/2007/ucm108967.htm. Accessed March 1, 2013.

2 Wagar EA, Yasin B, Yuan S. Point-of-Care Testing: Twenty Years’ Experience. LabMedicine. 2008;39(9):560-563.