What is the normal aPTT range for a patient on anticoagulation monitoring?

What is the normal aPTT range for a patient on anticoagulation monitoring?

• A. 60-90 seconds
• B. 20-35 seconds
• C. 40-60 seconds
• D. 10-20 seconds

Answer: (B)

The main idea here is that aPTT is used to gauge how long it takes blood to clot via the intrinsic pathway, and it has a normal reference range that labs report. The normal aPTT is usually about 25 to 35 seconds (often cited as roughly 20–35 seconds because normal ranges vary by lab). When a patient is on anticoagulation monitoring, you compare their aPTT to that normal reference to see how far the clotting time is from baseline, though the therapeutic target is longer than normal and depends on the protocol.

So the option that matches the typical normal range is 20–35 seconds. The other ranges are outside what most labs consider normal: 60–90 seconds is clearly prolonged beyond normal, 40–60 seconds is also above the usual normal reference, and 10–20 seconds is below normal.