Protein S Functional / Activity
How to prepare
You can eat and drink normally before the test.
No special preparation needed.
Tell our phlebotomist about any medicines you take. Don't stop them without asking your doctor.
Wear a loose sleeve so the sample can be taken easily from your arm.
How it works
About this test
Protein S is a natural blood thinner that keeps clotting in check. Low activity raises the risk of blood clots in veins.
Why is this test done?
- Investigate clots at a young age
- Investigate repeated clots or family history
- Investigate pregnancy loss
Symptoms — when should you get tested?
- Leg swelling and pain
- Clot in lungs
- Family history of clots
Normal range
Reference ranges differ slightly between labs, methods, age and sex. Always discuss your report with your doctor.
If your result is high
High protein S is not usually a problem.
If your result is low
Low protein S increases the risk of blood clots.
Common reasons- Inherited protein S deficiency
- Pregnancy or hormone pills
- Warfarin
- Liver disease or recent clot
How is the test done?
- 1Book online
Choose your slot for home collection or a visit to our centre.
- 2Blood sample taken
A trained phlebotomist takes a small blood sample from a vein in your arm with a sealed, single-use needle. It takes about 2 minutes.
- 3Tested in our lab
Your barcoded sample is tested on automated machines with strict quality checks.
- 4Report on WhatsApp
A pathologist checks the result and the report reaches you on WhatsApp and email.
Frequently asked questions
Only if your doctor advises; warfarin lowers protein S.
No fasting is needed for this test. You can eat and drink normally.
Your report is usually ready in 24-48 hrs after the sample reaches our lab. We send it on WhatsApp and email, and you can also download it from the Reports page.
Please call our team to confirm whether home sample collection is available for your location and test.
This test needs a blood sample. No special preparation needed.