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DNA Labs India

Protein S Antigen Total Test

DNA Labs India | ISO 9001:2015 Certified

Protein S Antigen Total Test

Short Name: Protein C Functional

Also known as: Protein C Activity Test, Protein C Functional Assay, Functional Protein C Assay

Protein S Antigen Total Test test available at DNA Labs India for ₹5,500. Uses Chromogenic Assay on Whole blood (Citrated Plasma) samples. Results in Samples received by 11 am are reported the same day. You will receive your report via online portal, email, or WhatsApp.. Free home collection in 300+ cities across India.

Blood TestAll Ages🏠 Home Collection

✍️ Written By

🩺 Medically Reviewed By

Dr SULOCHANA HEMCHANDRA HOLLA

Dr SULOCHANA HEMCHANDRA HOLLA

Consultant Medical Geneticist · Reg: 8532

Last reviewed: September 7, 2026

Overview

This assay should be used as the initial test for evaluating patients suspected of Congenital Protein C deficiency including those with family history of thrombotic events. It also helps to identify decreased Functional Protein C of acquired origin e.g. due to oral anticoagulant effect, Vitamin K deficiency, Liver disease or DIC.

Test Code
3577
CPT Code
85303
ICD Code
D68.59
Price
₹5,500
Sample Type
Whole blood (Citrated Plasma)
Result Time
Samples received by 11 am are reported the same day. You will receive your report via online portal, email, or WhatsApp.
Fasting Required
Yes (10 hours)
Method
Chromogenic Assay
Step 1

Sample Collection

Overnight fasting is preferred. It is recommended that the patient discontinues Heparin for 1 day and Oral Anticoagulants for 7 days prior to sampling, as these drugs may affect test results. Discontinuation should only be done with prior consent from the treating physician. A duly filled Coagulation Requisition Form (Form 15) is mandatory.

Method: Venipuncture

Step 2

Laboratory Analysis

A 3 mL blood sample will be collected by venipuncture into a Blue Top (Sodium Citrate) tube. The tube should be mixed thoroughly by gentle inversion. The procedure is quick and carries minimal discomfort.

Step 3

Report Delivery

The sample should be transported to the laboratory within 4 hours. If a delay is expected, platelet-poor plasma (PPP) must be prepared within 1 hour of collection and frozen immediately. Do not thaw frozen samples. Resume normal diet and activities unless advised otherwise; keep the puncture site clean and apply pressure if bleeding occurs.

Timeline: Samples received by 11 am are reported the same day. You will receive your report via online portal, email, or WhatsApp.

Patient Instructions

1
Before the Test:Overnight fasting is preferred. Inform your doctor about all medications. Discontinue Heparin for 1 day and oral anticoagulants for 7 days prior to sampling, only with prior consent from your treating physician. Carry the duly filled Coagulation Requisition Form (Form 15).
2
During the Test:A blood sample will be drawn from a vein in your arm using a sterile needle. The procedure takes about 5 minutes. You may feel a mild prick and slight pressure at the puncture site.
3
After the Test:You can resume normal activities immediately after the blood draw. Keep the pressure bandage on for a few hours to prevent bruising. Contact the lab if you notice excessive bleeding or swelling.

About This Test

Who Should Get This Test

This assay should be used as the initial test for evaluating patients suspected of Congenital Protein C deficiency including those with family history of thrombotic events. It also helps to identify decreased Functional Protein C of acquired origin e.g. due to oral anticoagulant effect, Vitamin K deficiency, Liver disease or DIC.

How to Prepare

  • Collect 3 mL whole blood in a Blue Top (Sodium Citrate) tube.
  • Mix thoroughly by inversion.
  • Transport to lab within 4 hours. If delayed, prepare platelet-poor plasma within 1 hour as per protocol and freeze immediately.
  • Do not thaw frozen samples.
  • Overnight fasting is preferred.
  • Submit duly filled Coagulation Requisition Form (Form 15).

Doctor's Notes

Reviewed by — MBBS, MD (Medical Genetics) · Reg. No. 8532

"The protein C functional assay is the recommended initial test for suspected protein C deficiency. A low result should always be interpreted in the clinical context, as anticoagulants and acute thrombosis can transiently lower activity levels."

Last medically reviewed: September 7, 2026

Test Parameters & Specifications

Sample TypeWhole blood (Citrated Plasma)
Sample Volume3 mL
ContainerBlue Top (Sodium Citrate) tube
Collection MethodVenipuncture

Sample Stability

Room Temperature (20-25°C)4 hours
Refrigerator (2-8°C)4 hours
Frozen (-20°C)2 weeks
Sample Rejection Criteria:
  • Clotted or haemolysed sample
  • Sample received more than 4 hours after collection without proper handling
  • Frozen sample thawed during transport
  • Improper tube (non-citrate tube) or underfilled tube
  • Missing Coagulation Requisition Form (Form 15)
  • Patient on anticoagulants without physician approval for discontinuation

Understanding Your Results

The protein C functional assay measures the activity of protein C in plasma. Results are interpreted in the context of clinical history, medication use, and other coagulation test results.
📊

Low functional activity + low antigen

📊

Low functional activity + normal antigen

📊

Normal functional activity

📊

Elevated functional activity

⚠️ When to Consult a Doctor:

If you experience symptoms of blood clots such as pain, swelling, warmth, and redness in a limb, sudden shortness of breath, chest pain, coughing up blood, headaches, or dizziness, seek medical attention immediately. Also consult your doctor if you have a family history of protein C deficiency or unprovoked thrombosis.

Limitations

  • ⚠Results may be falsely low during acute thrombosis or with active anticoagulation.
  • ⚠A single low result is not diagnostic; confirmatory testing is recommended.
  • ⚠Type II deficiency with normal antigen but low activity requires specialised testing.
  • ⚠Age-specific reference ranges apply to neonates and infants.
  • ⚠Reference ranges vary by laboratory and assay kit.

Risks & Considerations

  • ●Bruising or slight pain at the puncture site
  • ●Dizziness or lightheadedness during blood draw
  • ●Infection (rare, prevented by aseptic technique)

Interfering Factors

  • ●Warfarin / oral anticoagulants within 7 days
  • ●Heparin within 1 day
  • ●Vitamin K deficiency
  • ●Liver disease
  • ●Disseminated intravascular coagulation (DIC)
  • ●Acute thrombotic episode (consumption of protein C)
  • ●Use of certain antibiotics / chemotherapy (rare)
  • ●Improper sample handling (clotting, hemolysis, prolonged storage)

Compare With Similar Tests

TestProtein S Antigen Total Test
ComparisonProtein S Antigen Total Test

Frequently Asked Questions

What is the Protein C Functional Test?
It is a blood test that measures the functional activity of protein C, a natural anticoagulant. The test helps determine whether your protein C is working properly to prevent blood clots.
Why is the Protein C Functional Test done?
It is done to screen for congenital or acquired protein C deficiency in people with unexplained or recurrent blood clots, early-age thrombosis, unusual-site clots, or a family history of protein C deficiency.
What is the cost of the Protein C Functional Test in India?
At DNA Labs India, the cost is INR 5500. This includes free home sample collection in many cities. Other labs may charge differently.
Do I need to fast before the Protein C Functional Test?
Overnight fasting is preferred. However, it is not mandatory unless your doctor advises otherwise. Drink water and follow your physician's instructions.
How is the Protein C Functional Test performed?
A 3 mL whole blood sample is collected in a Blue Top (Sodium Citrate) tube, and the plasma is analysed using a chromogenic assay.
What does a low Protein C functional level mean?
It indicates reduced protein C activity, which could be due to congenital deficiency, liver disease, vitamin K deficiency, DIC, or anticoagulant use. Confirmatory tests are required.
Can anticoagulant medications affect my test results?
Yes. Heparin should be stopped for 1 day and oral anticoagulants for 7 days before the test, only with your doctor's consent. These drugs can lower protein C activity and produce false low results.
What is the difference between Protein C functional and antigen tests?
The functional test measures protein C activity (how well it works). The antigen test measures the total amount of protein C protein. Combining both helps distinguish type I (low quantity) from type II (low function) deficiencies.
Is home sample collection available for the Protein C Functional Test?
Yes, DNA Labs India offers free home sample collection for online bookings in 150+ Indian cities, including Mumbai, Delhi, Bengaluru, Hyderabad, Chennai, Kolkata, Pune, and more.
When will I get my Protein C Functional Test report?
If the sample reaches the lab by 11 am, the report is typically available the same day. You can access it online, by email, or via WhatsApp.
Who should get tested for Protein C deficiency?
People with a history of unprovoked or recurrent venous thrombosis, thrombosis at a young age (<50 years), thrombosis at unusual sites, recurrent pregnancy loss, or a close family member with protein C deficiency should consider testing.
Can Protein C deficiency cause problems during pregnancy?
Yes, it increases the risk of venous thromboembolism during pregnancy and postpartum. Pregnant women with known protein C deficiency may require anticoagulant prophylaxis and specialist obstetric care.
Worried about the process? Our certified phlebotomists collect thousands of samples every month across India. The process takes under 5 minutes and is virtually painless. Questions? Message us on WhatsApp — we're here 7 days a week.

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