These tests are used to measure how long it takes a person's blood to clot. PT and PTT tests
are often done for people taking blood thinners or anticoagulant medications such as Warfarin
and Heparin to help determine their optimal dosage. They can also be used to help diagnose
people with bleeding disorders or blood clots. The PT test also includes a measurement
for International Normalized Ratio (INR). Results for these tests should be interpreted by a
These tests are sometimes ordered along with a Complete Blood Count (CBC).