Protein C - Functional – BC256
🩸 Coagulation & Clotting TestReport: Same Day
Sample Type: Blood (Citrated Plasma)
Test Code: BC256
The Protein C - Functional test measures the activity of Protein C, a vital protein in the blood that acts as a natural anticoagulant. Its primary job is to regulate the clotting process and prevent excessive or inappropriate blood clots from forming. This "functional" assay checks how well your Protein C is working.
✔ A key test in a thrombophilia workup to investigate the cause of unexplained blood clots (thrombosis).
✔ Helps diagnose hereditary or acquired Protein C deficiency.
✔ Recommended for patients with a personal or family history of abnormal clotting.
✔ A simple blood test with same-day reporting.
Protein C: The Body's Natural Brake on Blood Clotting
Blood clotting (coagulation) is a life-saving process that stops bleeding after an injury. However, this system must be tightly regulated. If clots form too easily or do not dissolve properly, they can block blood vessels and lead to serious medical events like a deep vein thrombosis (DVT), pulmonary embolism (PE), or stroke. Protein C is one of the most important proteins that acts as a "brake" on the clotting cascade, keeping it in check.
A **Protein C deficiency** means this braking system is weak, leading to a hypercoagulable state where the body has an increased tendency to form dangerous blood clots. This deficiency can be inherited (genetic) or acquired later in life due to other medical conditions.
Why a "Functional" Test is Important
There are two ways to measure Protein C: an antigen test (which measures the *amount* of the protein) and a functional test (which measures the *activity* of the protein). The functional test is superior because it can detect both types of deficiencies:
- Type I Deficiency: Where both the amount and activity of Protein C are low.
- Type II Deficiency: A rarer type where a person has a normal amount of Protein C, but the protein is defective and does not work properly. An antigen test would miss this.
By measuring the activity, the functional test provides a more clinically relevant picture of a person's actual clotting risk.
When is This Test Ordered?
A doctor, typically a hematologist, will order this test as part of a "thrombophilia workup" if a patient has experienced:
- An unexplained blood clot, especially at a young age (under 50).
- Recurrent blood clots.
- A clot in an unusual location (e.g., veins of the abdomen or brain).
- A strong family history of abnormal blood clotting.
Frequently Asked Questions (FAQ)
Protein C is a natural anticoagulant. It acts as a brake on the blood clotting system, helping to prevent the formation of excessive or unnecessary blood clots and keeping your blood flowing smoothly.
A low level means you have Protein C deficiency. This indicates that your body's ability to regulate clotting is impaired, placing you at a higher risk of developing dangerous blood clots like DVT or pulmonary embolism.
It can be. Hereditary Protein C deficiency is a genetic disorder passed down through families. It can also be "acquired" due to other conditions such as severe liver disease, Vitamin K deficiency, or treatment with certain anticoagulant drugs like warfarin.
A functional test measures how well your Protein C is *working*. This is more important than just measuring the *amount* (antigen). You could have a normal amount of the protein, but if it's defective and doesn't function, you are still at risk. The functional test detects this problem.
Fasting is generally not required. However, it is crucial to inform your doctor about all medications you are taking, especially blood thinners like warfarin or heparin, as they can significantly affect the test results.