Partial Thromboplastin Time (PTT) normal value is?

Partial Thromboplastin Time (PTT) normal value is?

• A. 10-20 seconds
• B. 60-70 seconds
• C. 28-34 seconds
• D. 40-50 seconds

Answer: (C)

Normal PTT values reflect how long it takes for clot formation through the intrinsic pathway. In most labs, the reference range for a healthy person is about 28 to 34 seconds (roughly 25–35 seconds, depending on the reagents used). A result in the 10–20 second range would be unusually fast for PTT and is not within the normal PTT window. Values in the 40s or 60s indicate prolonged clotting time, which can occur with anticoagulation therapy (like heparin) or coagulation factor deficiencies. Hence, 28–34 seconds best represents the normal range.

Normal PTT values reflect how long it takes for clot formation through the intrinsic pathway. In most labs, the reference range for a healthy person is about 28 to 34 seconds (roughly 25–35 seconds, depending on the reagents used). A result in the 10–20 second range would be unusually fast for PTT and is not within the normal PTT window. Values in the 40s or 60s indicate prolonged clotting time, which can occur with anticoagulation therapy (like heparin) or coagulation factor deficiencies. Hence, 28–34 seconds best represents the normal range.