What is the normal prothrombin time (PT) range?

What is the normal prothrombin time (PT) range?

• A. ~9–12 seconds
• B. ~11–12 seconds
• C. ~14–16 seconds
• D. ~11–13.5 seconds

Answer: (D)

PT measures how long it takes blood to clot via the extrinsic pathway, reported in seconds. In healthy people, the normal range is about 11 to 13.5 seconds, though exact values can vary by lab due to different reagents. Among common choices, 11–13.5 seconds best fits that typical reference range. A value around 9–12 seconds would be unusually fast, while 14–16 seconds would indicate prolonged clotting. An 11–12 second range is normal but may not capture the upper end. So, 11–13.5 seconds is the most accurate representation of the normal PT range.

PT measures how long it takes blood to clot via the extrinsic pathway, reported in seconds. In healthy people, the normal range is about 11 to 13.5 seconds, though exact values can vary by lab due to different reagents. Among common choices, 11–13.5 seconds best fits that typical reference range. A value around 9–12 seconds would be unusually fast, while 14–16 seconds would indicate prolonged clotting. An 11–12 second range is normal but may not capture the upper end. So, 11–13.5 seconds is the most accurate representation of the normal PT range.