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Contact Protein (Serum) – Quantitative

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of contact protein in your blood serum. Contact protein is a protein involved in blood clotting and immune responses.

Quick summary

["Knowing your contact protein levels may help assess bleeding risks or immune function."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
94657-4
Short code
Case ID Contact
Synonyms
Case ID Contact
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is Contact Protein?

Contact protein is a blood protein that plays a role in the body’s clotting system and immune defense. It can be detected in serum, the liquid part of blood after clotting. While its exact function is still studied, it may help identify conditions affecting blood clotting or immune responses.

Why Might You Need This Test?

This test may be ordered if you have symptoms or conditions linked to abnormal clotting or immune responses, such as bleeding disorders, infections, or certain autoimmune diseases. Your healthcare provider may also use it as part of a broader evaluation.

How Is the Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The serum portion is separated and analyzed using a specialized laboratory method to measure contact protein concentration.

What Do Results Mean?

Results are compared to a general reference range for healthy individuals. Elevated or low levels may signal potential health concerns, but interpretation depends on clinical context and other test results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Contact Protein Level

Frequently asked questions

What causes contact protein levels to change?
Contact protein levels may vary due to underlying medical conditions (e.g., liver disease, infections, or autoimmune disorders), medications, or genetic factors. Your provider may also consider lifestyle factors like diet or recent illness.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times. Follow up with your healthcare provider for interpretation.
Can contact protein levels be affected by diet or supplements?
Dietary changes alone are unlikely to significantly alter contact protein levels, but certain medications (e.g., blood thinners) or supplements may influence results. Always discuss with your provider.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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