Protein S Functional / Activity Test
Short Name: Protein S Activity
Also known as: Protein S Antigen Total Test, Protein S Functional Test, Protein S Activity Test, Protein S Total Antigen
Protein S Functional / Activity Test test available at DNA Labs India for ₹20,000. Uses Immunoturbidimetric on Whole blood samples. Results in Reports are typically delivered within 2–3 weeks from the date of sample submission, as the test involves specialized processing.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr Pasupathy Arumugam
Consultant Pathologist · Reg: 21521
Last reviewed: September 7, 2026
Overview
This assay is indicated for the investigation of patients with a history of unexplained thrombosis or for the evaluation of inherited or acquired thrombophilia. It helps confirm the diagnosis of Protein S deficiency and aids in guiding long-term anticoagulation therapy.
- Test Code
- 3576
- Price
- ₹20,000
- Sample Type
- Whole blood
- Result Time
- Reports are typically delivered within 2–3 weeks from the date of sample submission, as the test involves specialized processing.
- Fasting Required
- Yes (8 hours)
- Method
- Immunoturbidimetric
Sample Collection
Overnight fasting is preferred. Inform your doctor about any medications you are taking, especially anticoagulants such as warfarin. If possible, avoid taking vitamin K antagonists for 2 weeks prior to testing, but only under medical guidance. Duly filled Coagulation Requisition Form (Form 15) and Test Send Out Consent Form (Form 35) are mandatory.
Method: Venipuncture
Laboratory Analysis
A healthcare professional will draw a blood sample from a vein in your arm using a blue top (sodium citrate) tube. The tube should be mixed thoroughly by inversion to prevent clotting. The process is quick and minimally invasive.
Report Delivery
After the blood draw, you can resume normal activities. A small bruise or tenderness at the puncture site may occur and usually resolves on its own. If you experience prolonged bleeding or discomfort, contact your healthcare provider.
Timeline: Reports are typically delivered within 2–3 weeks from the date of sample submission, as the test involves specialized processing.
Patient Instructions
About This Test
Who Should Get This Test
This assay is indicated for the investigation of patients with a history of unexplained thrombosis or for the evaluation of inherited or acquired thrombophilia. It helps confirm the diagnosis of Protein S deficiency and aids in guiding long-term anticoagulation therapy.
How to Prepare
- Collect 3 mL whole blood in 1 Blue Top (Sodium Citrate) tube
- Mix thoroughly by inverting the tube 3-4 times
- Transport to lab within 4 hours at room temperature
- If transport is delayed, prepare Platelet Poor Plasma (PPP) within 1 hour by centrifuging at 3600 rpm for 15 minutes; transfer supernatant to a clean plastic screw-capped vial and freeze immediately
- Ship frozen; do not thaw
- Overnight fasting is preferred
Doctor's Notes
Reviewed by Dr Pasupathy Arumugam — MBBS, MD (Pathology) · Reg. No. 21521
"Protein S deficiency is a significant risk factor for venous thromboembolism. A functional activity test helps assess the anticoagulant capacity of protein S, guiding appropriate antithrombotic therapy."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Clotted or hemolyzed sample
- Incorrect anticoagulant ratio (under-filled tube)
- Delayed transport without PPP preparation
- Sample thawed during transport
Understanding Your Results
Normal
Type I Deficiency
Type II Deficiency
Acquired Deficiency
Consult a doctor if you experience unexplained swelling or pain in the legs, sudden chest pain, shortness of breath, or coughing up blood. Also seek medical advice if you have a family history of blood clots, recurrent miscarriages, or have been diagnosed with thrombophilia for appropriate management.
Limitations
- ⚠Functional assays can be unreliable in patients currently receiving vitamin K antagonists; results must be interpreted with caution
- ⚠A low Protein S level should be confirmed with a repeat test after 6 weeks to distinguish transient from persistent deficiency
- ⚠Genetic testing may be required to identify the specific mutation for definitive diagnosis
- ⚠Sample must be processed promptly; delayed processing may yield false results
Risks & Considerations
- ●Slight pain or bruising at the needle site
- ●Lightheadedness or fainting during blood draw
- ●Infection (rare, due to sterile technique)
- ●Excessive bleeding (rare, but if it occurs, apply pressure and seek medical help)
Interfering Factors
- ●Anticoagulant therapy (warfarin, vitamin K antagonists) may lower Protein S levels
- ●Pregnancy and oral contraceptive use decrease Protein S levels
- ●Acute thrombosis may transiently reduce Protein S activity
- ●Liver disease and vitamin K deficiency affect protein synthesis
- ●Inflammatory conditions can alter protein levels
Compare With Similar Tests
| Test | Protein S Functional / Activity Test | Protein C Functional/Activity Test | Antithrombin III Test | Factor V Leiden Mutation Test |
|---|---|---|---|---|
| Comparison | Protein S Functional / Activity Test |
Frequently Asked Questions
What is the Protein S Functional / Activity Test?
Why is this test prescribed?
What are the symptoms of Protein S deficiency?
How is the test performed?
Do I need to fast before the test?
What is the cost of the Protein S Functional / Activity Test?
Is home sample collection available?
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