During the test
Obtaining the blood sample for prothrombin time testing usually takes just a few minutes, like any other blood test.
After the test
Your blood might be sent to a laboratory for analysis. If the laboratory analysis is done on-site, you could have your test results within hours. If your doctor sends your blood to an off-site laboratory, it may take several days to receive the results.
In some anticoagulation clinics, a nurse will take a sample of your blood with a finger stick, and give you the test result within minutes, while you are still in the exam room.
Home testing kits are available for people who have to take blood thinners for long periods and who have been trained in taking blood samples and testing them.