C3 Protein (Fibrinogen) Screening Test
This test measures the amount of fibrinogen, a blood protein that helps form clots. It may be ordered to assess bleeding risk, clotting disorders, or liver function.
["Fibrinogen helps your blood clot properly and supports liver health—low levels may signal bleeding risks or liver issues."]
Key facts at a glance
- LOINC
- 44714-4
- Short code
- C3RATIO
- Synonyms
- C3/Prot Snv
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile, screw-capped, leak-proof synovial fluid collection tube; plain tube without anticoagulant preferred for complement analysis. Transport to laboratory promptly at room temperature.
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunonephelometry
- CPT
- 86160
- SNOMED
- 105001000119101
- Specimen volume
- 1-2 mL of synovial fluid
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 24 hours; Frozen (-20°C or below): up to 4 weeks. Avoid repeated freeze-thaw cycles. Centrifuge synovial fluid prior to analysis if turbid.
- Hemolysis max
- 300
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your doctor may recommend this test if you have symptoms like easy bruising, excessive bleeding, or unexplained fatigue. It’s also used to monitor conditions like liver disease, DIC (disseminated intravascular coagulation), or after surgery to prevent clots.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re on blood thinners, check with your doctor first.
How the Test Results Are Used
Low fibrinogen levels may indicate bleeding disorders, liver problems, or severe infections. High levels could suggest inflammation, dehydration, or certain clotting disorders. Your doctor will interpret results in context with your symptoms and medical history.
Common Conditions Linked to Fibrinogen Levels
Abnormally low fibrinogen is often seen in liver disease, clotting disorders like hemophilia, or conditions like DIC. High levels may appear with infections, burns, or certain cancers.
Reference range
No established reference range; results expressed as C3/total protein mass ratio. Interpretation is based on comparison with serum C3/total protein ratio and clinical context.N/A
No fasting required. The joint aspiration site should be cleaned with antiseptic. Local anesthesia may be used prior to arthrocentesis. Patient should be informed of procedural risks including infection, bleeding, and joint damage.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Fibrinogen plays a critical role in blood clotting and liver function. It’s part of the body’s natural response to injury or infection. Monitoring levels helps diagnose or manage bleeding risks, liver health, or inflammatory conditions.
Short name
Fibrinogen Level Check
Frequently asked questions
What causes low fibrinogen levels?
What causes high fibrinogen levels?
Does diet affect fibrinogen levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy