Final answer:
PT is the lab abbreviation for Prothrombin time, which measures how long it takes for blood to clot.
Step-by-step explanation:
PT is the lab abbreviation for Prothrombin time. Prothrombin time measures how long it takes for blood to clot. It is used to monitor the effectiveness of blood-thinning medications and to diagnose bleeding disorders. The test measures the time it takes for prothrombin, a protein in the blood, to be converted to thrombin, which is necessary for clot formation.