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Protein C (Mass Concentration) in Plasma

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

This test measures the amount of Protein C, a natural blood protein that helps prevent blood clots from forming. It’s important for assessing your risk of clotting disorders.

Quick summary

["Protein C helps keep your blood from clotting too easily, and low levels may increase your risk of clots."]

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

Key facts at a glance

LOINC
5988-1
Short code
tPA 10M PPP Chro-mCnc
Synonyms
tPA 10M PPP Chro-mCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
chromo
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

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms of blood clots (such as swelling, pain, or redness in a leg or arm), a history of clotting disorders, or if you’re taking blood thinners. It may also be checked before surgery or if you have certain blood-related conditions.

What to Expect Before the Test

You’ll likely have a small needle inserted into your arm or hand to draw a blood sample. This is quick and usually doesn’t cause pain. Avoid eating or drinking for a few hours before the test if instructed.

What the Results Mean

Results help doctors determine if your Protein C levels are too low, which could raise your risk of clotting. Very low levels may require treatment or lifestyle changes to prevent complications.

Common Reasons for Testing

This test is often used to diagnose or monitor conditions like thrombophilia (a tendency to form clots) or to check if blood thinners are working properly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Protein C Level

Frequently asked questions

What causes Protein C levels to be low?
Low Protein C levels can be caused by genetic disorders, certain medications (like blood thinners), liver disease, or conditions that increase inflammation. Lifestyle factors, such as obesity or smoking, may also play a role.
How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on your lab. Your doctor will discuss them with you during your follow-up visit.
Can I eat or drink before this test?
Follow your doctor’s instructions, but generally, you may have a light snack or drink water unless otherwise directed. Avoid heavy meals or alcohol before testing.
  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