Protein S Activity Test: Booking, Price, and Results
About Protein S Activity Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | Functional Protein S Test, Protein S Activity Plasma Test, Functional Protein S Test, Free Protein S Activity Test |
| Sample Type | Venous blood (citrated plasma) |
| Festing Required | Not mandatory; some laboratories may prefer overnight fasting |
| Report Time | 2 to 4 business days |
| Recommended For | Adults of all genders; paediatric use with age-specific ranges |
| Price | Starting at ₹1,950 |
What Is a Protein S Activity Test?
The protein S activity test measures how well protein S, a natural blood-clotting regulator, is working in your body. Protein S helps prevent excessive clot formation, and low levels can raise the risk of abnormal clotting. Also called the functional protein S or protein S activity plasma test, this test uses a blood sample drawn from a vein. Doctors typically order it when investigating unexplained blood clots or clotting disorders.
What Does a Protein S Activity Test Measure?
The protein S test evaluates the functional activity of protein S in your plasma. Protein S is a vitamin K-dependent protein that acts as a helper molecule for activated protein C, which inactivates certain clotting factors (Va and VIIIa) that promote clot formation. Only the free form of protein S is active; approximately 65% circulates in a bound, inactive form. The test measures how effectively the free form performs its anticoagulant role.
The table below summarises the parameters assessed:
| Parameter | Description |
|---|---|
| Protein S Activity | Measures functional activity as a percentage of normal |
Why Is a Protein S Activity Test Done?
This test is ordered when a doctor needs to assess how well your body's natural clot-prevention system is working.
Common Symptoms That May Require This Test
Several symptoms may prompt a doctor to request a protein S activity test:
- Leg swelling or pain, which may suggest a blood clot in a deep vein
- Shortness of breath or chest pain that could indicate clots in the lungs
- Unexplained, recurrent blood clots at an unusual age
- Recurrent pregnancy loss without a clear cause
- Family history of clotting disorders
- Stroke in children with a severe form of the protein S deficiency
Conditions This Test Can Help Detect
The test can help identify a range of clotting-related conditions:
- Protein S deficiency, both hereditary and acquired
- Deep vein thrombosis (DVT), where clots form in the veins of the legs or pelvis
- Pulmonary embolism, where a clot travels to and blocks blood flow in the lungs
- Pregnancy complications such as recurrent miscarriage or placental issues
- Thrombophilia (a tendency to form blood clots) in relatives of affected individuals
Protein S Activity Test During Pregnancy
Functional protein S levels considerably decrease during pregnancy and in the weeks after delivery. This is a normal physiological change, but it can make test results harder to interpret. If testing is needed due to a history of recurrent clots or pregnancy loss, doctors use pregnancy-specific reference ranges. In general, testing is best deferred until after pregnancy and the postpartum period for clearer results.
How to Prepare and What to Expect
Understanding what is needed before your test helps ensure an accurate result.
Do You Need to Fast?
No fasting is required for the protein S activity test. Some laboratories may still prefer an overnight fast, so it is worth checking with your collection centre when booking.
Practical Tips Before Your Test
A few steps before your appointment can help produce a reliable sample:
- Stop warfarin at least two weeks before the test, but only after consulting your doctor
- Avoid heparin therapy for at least two days before sample collection
- Inform your doctor about all current medications, including oral contraceptives and hormone therapy
- Avoid testing during an acute illness or shortly after a clotting episode; wait several weeks to allow levels to stabilise
- Wear a short-sleeved or loose-sleeved top for easy blood collection
Step-by-Step Procedure
Here is what to expect during sample collection:
- A trained phlebotomist cleans the skin over a vein, usually in the inner elbow area.
- A small needle is used to draw blood into a special blue-top tube containing sodium citrate, which prevents the sample from clotting.
- The tube is gently inverted several times to properly mix the blood and citrate solution.
- The sample is sent to the laboratory, where it is centrifuged to separate the plasma.
- The plasma is frozen and stored at very low temperatures until the functional assay is run.
- A clot-based functional test is performed to determine how much active protein S is present in your plasma.
Factors That Can Affect Accuracy
Several factors may influence your protein S activity result:
- Warfarin, heparin, or other anticoagulant medications
- Oral contraceptives and hormone replacement therapy
- Pregnancy and the postpartum period
- Lupus anticoagulant or Factor V Leiden mutation in the blood
- Liver disease, vitamin K deficiency, or recent acute infection
- High fat (lipid) levels in the blood or platelet contamination of the sample
Understanding Your Protein S Activity Test Results
Results should always be reviewed with your doctor, who will consider your full health history alongside the numbers.
| Parameter | Low | Normal | High |
|---|---|---|---|
| Protein S Activity (Males) | Below 65% | 65% to 150% | Above 150% |
| Protein S Activity (Females under 50) | Below 50% | 50% to 150% | Above 150% |
| Protein S Activity (Females 50 and above) | Below 65% | 65% to 150% | Above 150% |
These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
- Pregnancy and oral contraceptive use cause protein S levels to drop naturally, which can produce a falsely low reading.
- Testing during acute thrombosis, liver disease, or warfarin therapy can also push levels into the deficient range without a true underlying deficiency.
- Heparin or lupus anticoagulants in the blood can cause the assay to overestimate protein S activity, producing a misleadingly normal or high result.
How to Maintain Healthy Levels
These general wellness steps may support healthy clotting function:
- Eat a balanced diet that includes vitamin K-rich foods such as green leafy vegetables, which support protein S production.
- Stay well hydrated, especially ahead of blood collection.
- Always share a complete list of your medicines and supplements with your doctor before testing.
Lupin Diagnostics Protein S Activity Test Price and Home Collection
The protein S activity Test is available at Lupin Diagnostics starting at ₹1,950. Home sample collection is available across locations for added convenience.
| City | Approximate Price (₹) |
|---|---|
| Pune | ₹1,950 |
| Mumbai | ₹1,950 |
| Indore | ₹1,950 |
| Bengaluru | ₹1,950 |
| Chennai | ₹1,950 |
| Hyderabad | ₹1,950 |
| Kolkata | ₹1,950 |
Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
Lupin Diagnostics offers home sample collection across cities, so you can get the functional protein S test done without visiting a centre. All samples are processed in NABL-accredited laboratories by trained staff. Your digital report is delivered directly to your phone or email once ready.
Frequently Asked Questions
This test is used to diagnose inherited or acquired protein S deficiency. Doctors order it when evaluating people with a history of unexplained blood clots or suspected thrombophilia (a condition where your blood clots more easily). It is also used to assess family members of individuals already diagnosed with a clotting disorder.
The protein S activity test is typically recommended for adults with recurrent, unexplained blood clots, especially when they occur at a young age or in unusual locations. People with a close family member diagnosed with protein S deficiency, or women with a history of recurrent miscarriage, may also be advised to take this test.
Warfarin should be stopped at least two weeks before the protein S activity test, and heparin at least two days before. However, never stop any medication without first speaking to your doctor. Always inform the lab and your doctor about all medicines, including contraceptives and hormone therapy.
It is generally best to avoid testing for protein S deficiency during pregnancy or shortly after delivery, as levels naturally decline during this period and can yield misleading results. If testing is necessary for clinical reasons, your doctor will use appropriate reference ranges for pregnancy.
A low result means your body may not have enough functional protein S to regulate blood clotting effectively. This increases the risk of abnormal clots, such as DVT or pulmonary embolism. The cause may be inherited or acquired, and your doctor will carry out further assessment to determine the reason and appropriate next steps.
Yes, there are three recognised types. Type I involves low total and free protein S levels. Type II involves normal antigen levels but reduced functional activity. Type III involves low free protein S levels with a normal total concentration. The functional protein S test specifically assesses activity, which helps distinguish between these types.
Reports for the protein S activity plasma test are typically ready within 5 business days. Lupin Diagnostics delivers reports digitally via email or WhatsApp, so you can share them with your doctor promptly.
Protein S Activity Test: Booking, Price, and Results
