Quick Facts
- Sample: Blood
- Fasting: No fasting required. Inform your healthcare provider or laboratory about all medications, especially blood thinners such as warfarin, as they may affect protein C levels; do not stop prescribed medications unless instructed, and if possible, avoid testing during an acute blood-clotting event.
- Turnaround: 6-8 days. May take longer based on weather, holidays, or lab delays.
What This Test Measures
The Protein C Antigen Blood Test measures the amount of Protein C antigen (also known as Protein C Immunologic) present in your blood. This is an antigen level measurement, meaning it quantifies the presence of the Protein C protein itself, using a blood sample.
Protein C is a protein involved in regulating blood clotting. This test helps confirm and characterize protein C deficiency, a condition associated with an increased risk of developing abnormal blood clots, such as deep vein thrombosis (DVT) or pulmonary embolism (PE).
Benefits
- Measures Protein C antigen levels from a single blood sample.
- Helps confirm suspected protein C deficiency.
- Supports characterization of protein C deficiency alongside clinical evaluation.
- Requires no fasting or special dietary preparation.
- Results delivered online for convenient access.
Who Is This Test For?
- People whose healthcare provider suspects protein C deficiency.
- Individuals with a personal history of unexplained blood clots.
- Individuals with a family history of protein C deficiency.
- People being evaluated for recurrent DVT or pulmonary embolism.
- Individuals whose healthcare provider recommends this test as part of clotting risk evaluation.
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What is the purpose of this test?
This test measures Protein C antigen levels in your blood to help a healthcare provider evaluate whether protein C deficiency may be present or contributing to abnormal blood clotting. It is not intended to diagnose a condition on its own and is best interpreted alongside a broader clinical evaluation.
2. Who should consider this test, and when should it be ordered?
This test may be appropriate if a healthcare provider suspects protein C deficiency, particularly for individuals with a personal or family history of unexplained blood clots such as DVT or pulmonary embolism, or as part of an evaluation for recurrent clotting events. Consider ordering this test when a healthcare provider recommends evaluating your protein C status, such as following an unexplained blood clot or when investigating a family history of clotting disorders. This test is intended to support evaluation, not to replace a full medical assessment.
3. What does this test specifically measure?
This test measures the antigen level of Protein C, also known as Protein C Immunologic — the quantity of the Protein C protein present in your blood, rather than its functional activity. This antigen-versus-activity distinction is an important factor to keep in mind when interpreting your results.
4. Do I need to fast before this test?
No fasting is required for this test. Inform your healthcare provider or laboratory about all medications you are taking, especially blood thinners or vitamin K antagonists such as warfarin, as these may affect protein C levels. Do not stop prescribed medication unless instructed by your healthcare provider. If possible, avoid testing during an acute blood clotting event, as protein C levels may be temporarily altered.
5. How quickly will I get results?
Results are typically available within 6-8 days. This may take longer based on weather, holidays, or lab delays.
6. How do I interpret the results?
The meaning of your Protein C antigen result depends on your individual clinical context, including your symptoms, medical history, current medications, timing of the test, and other laboratory findings. Because this test reflects an antigen level rather than functional activity, results should be interpreted with that distinction in mind. An abnormal result does not automatically confirm protein C deficiency, and a normal result does not rule it out. Always discuss your results with a qualified healthcare provider.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
7. What should I do if my results are abnormal?
If your results fall outside the expected range, review them with a qualified healthcare provider. They can help determine whether additional evaluation or testing is appropriate based on your overall health and medical history. Do not start, stop, or change any medication without guidance from your healthcare provider.
8. How often should I get tested?
There is no standard testing frequency for this test. How often you are tested should be determined by your healthcare provider, based on your individual clinical situation and reason for testing.
Pre-test preparation
No fasting is required for this test. Inform your healthcare provider or laboratory about all medications you are taking, especially blood thinners (anticoagulants) or vitamin K antagonists (such as warfarin), as these may affect protein C levels. Do not stop prescribed medication unless instructed by your healthcare provider. If possible, avoid testing during an acute blood-clotting event, as protein C levels may be temporarily altered. Follow any additional instructions provided by your healthcare provider or testing facility.
