Which laboratory value is measured in seconds?

Which laboratory value is measured in seconds?

• A. WBC
• B. Platelet
• C. Hb
• D. PT

Answer: (D)

Time-based lab tests are reported in seconds; the prothrombin time is one of them. PT measures how long it takes plasma to clot after adding tissue factor, so the result is a duration expressed in seconds (with typical ranges around 11–13.5 seconds, though this varies by lab). In contrast, white blood cell count and platelets are reported as cell counts (per microliter or per liter), and hemoglobin is reported in grams per deciliter. So the value measured in seconds is the prothrombin time.

Time-based lab tests are reported in seconds; the prothrombin time is one of them. PT measures how long it takes plasma to clot after adding tissue factor, so the result is a duration expressed in seconds (with typical ranges around 11–13.5 seconds, though this varies by lab). In contrast, white blood cell count and platelets are reported as cell counts (per microliter or per liter), and hemoglobin is reported in grams per deciliter. So the value measured in seconds is the prothrombin time.