What is Activated Partial Thromboplastin Time (aPTT)?
Activated Partial Thromboplastin Time is measured as part of a coagulation panel. Your aPTT is normal — this part of your clotting system is working as expected.
What does a high Activated Partial Thromboplastin Time mean?
Your aPTT is prolonged, meaning this clotting pathway takes longer than usual. Causes include heparin, clotting-factor deficiencies, or certain antibodies.
If markedly elevated: Your aPTT is markedly prolonged and should be evaluated promptly for bleeding risk.
Understand your whole report, not just one number
A single value rarely tells the full story — Activated Partial Thromboplastin Time is best read alongside the rest of your panel. Paste your values or upload your report and get a plain-English explanation of every marker, with the important results flagged.