Activated Partial Thromboplastin Time (aPTT) Test
How long it takes blood to clot via the intrinsic pathway. Used to monitor heparin therapy and screen for clotting disorders.
What is Activated Partial Thromboplastin Time (aPTT)?
How long it takes blood to clot via the intrinsic pathway. Used to monitor heparin therapy and screen for clotting disorders.
Find a Activated Partial Thromboplastin Time (aPTT) test
We offer panels that include this marker. Browse to find the best fit.
Browse testsActivated Partial Thromboplastin Time (aPTT) Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 25.0 – 35.0 seconds |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
What your Activated Partial Thromboplastin Time (aPTT) result may mean
Often reflects heparin therapy, factor deficiencies, or specific clotting inhibitors.
Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
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Frequently asked
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