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FRIDAY, June 13 (HealthDayNews) -- A laboratory test that quickly measures the amount and speed that the enzyme thrombin is produced in a person's blood has been developed by researchers at Virginia Commonwealth University.

Thrombin is an important enzyme that activates blood platelets to begin the clotting process.

The new test may help doctors better target drugs to control a variety of blood-clotting problems, including uncontrolled bleeding in hemophiliacs, hemorrhaging in accident victims, and excessive clotting that can result in life-threatening thrombosis.

Using the new test, the researchers measured how long it takes for thrombin to form in normal blood, in blood from people with coronary artery disease and in blood from hemophiliacs.

The study of 40 people found it takes between six and seven minutes for blood to start clotting in healthy people, average age 45. That process took nearly three times longer -- between 10 and 19 minutes -- in blood from people with hemophilia.

In people with coronary artery disease, clotting began much sooner -- in about four minutes -- than in the other groups. And the clots in the people with coronary artery disease were twice as rigid as those formed in the blood of healthy people.

The test takes about 10 minutes, and requires 700 microliters of blood. Unlike many current tests, it doesn't require that the blood first be separated into plasma and cells.

The study appears in this week's online issue of the Journal of Thrombosis and Haemostatsis.

More information

Here's where you can learn more about bleeding disorders.