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Date: Thursday, March 13, 1997
FOR IMMEDIATE RELEASE
Contact: Food and Drug Administration, Sharon Snider(301)443­3285
Broadcast Media: (301) 827­3434, Consumer Hotline:(800) 532­4440

FDA Clears First Home Test for Blood Clotting

The Food and Drug Administration has cleared for marketing the first home test for use with blood thinning medicine. The convenient, new test is intended for use by heart patients and others who are taking the blood thinning drug warfarin (Coumadin) to prevent clotting.

The ProTime Microcoagulation System, made by International Technidyne Corp., of Edison, N.J., is a simple finger stick test in which the user pricks his finger with a needle to draw blood, then runs the sample through a small, hand­held electronic device which displays the results on a screen.

The test, known as a prothrombin time (PT) test, is already cleared by FDA for use in physician offices, clinics and nursing homes to test for blood coagulation. The new system will now be available by prescription for home use under a doctor's supervision.

"People on blood thinning medicine need to be monitored closely by their doctors to make sure they are getting the right dose. It is critical that they not get too much or too little, and the drug level can change easily," said Bruce Burlington, M.D., director of FDA's Center for Devices and Radiological Health.

"Home tests will make it easier to do this. They will permit more frequent testing, allow closer monitoring, and will enable people to check at any time to see if their blood thinner is working properly."

Blood thinners are used to treat people with artificial heart valves, irregular heart beat and other conditions that lead to excessive blood clotting. These drugs have a narrow therapeutic range. If the drug level is too high, the patient can hemorrhage. If it is too low, clots can form and obstruct blood vessels, causing stroke and even death.

Currently, people taking these drugs are given a PT test every one or two months during regular visits to their doctor. With the new home test system, however, they will be able to test themselves weekly, or as often as their doctor recommends. The system stores the 40 most recent results with a date and time stamp, enabling the doctor to review and interpret the results and adjust the blood thinner accordingly.

The system can be programmed by the doctor with the appropriate upper and lower blood clotting range for each patient. The system displays "In Range" if the results are within the limits and "INR High" or "INR Low" if the results are too high or too low. If the results are out of range, the patient is instructed to re­test himself to confirm and then call the doctor immediately.

FDA's decision to clear the test system for home use was based on comparison data collected by the manufacturer on 84 patients at four clinics. The patients were tested at the clinics by health professionals using the professional laboratory PT test. The patients also tested themselves at home with the new system. The results proved comparable.

The Pro­time test system has been cleared only for use by patients taking warfarin. Its accuracy has not been studied with any other blood thinning drugs.

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