APTT (activated partial thromboplastin time) measures another clotting pathway.
- Normal range (adults)
- 25–35 seconds
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- aPTT, Activated Partial Thromboplastin Time, PTT, Partial Thromboplastin Time, PTTK
APTT normal range
| Group | secondsSame unit in all countries |
|---|---|
| Adults | 25–35 |
Ranges vary slightly between laboratories. The range printed on your own report is the one to go by.
Why is the APTT test done?
It is checked before surgery, for unexplained bleeding, and to monitor heparin.
What does a high APTT level mean?
A prolonged APTT means slower clotting.
Common causes
- Heparin treatment
- Hemophilia and other clotting factor deficiencies
- Lupus anticoagulant (which paradoxically raises clot risk)
- Liver disease
Diet and lifestyle tips
- No specific diet; follow medical advice
When should you see a doctor?
Unexplained prolonged APTT needs further tests.
Last updated
This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.