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C-reactive protein (CRP) mass concentration in serum/plasma

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

This test measures the amount of C-reactive protein in your blood, a marker often checked for signs of inflammation.

Quick summary

["CRP helps track inflammation, useful for monitoring conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
105126-7
Short code
CRP SerPlBld-mCnc
Synonyms
CRP SerPlBld-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
3
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86140
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 Is This Test Done?

Your doctor may order this test to check for inflammation in your body. Common reasons include monitoring conditions like rheumatoid arthritis, infections, or after surgery to ensure healing progresses as expected.

What Does a High or Low CRP Level Mean?

Elevated CRP levels may indicate inflammation, but they can also be influenced by factors like fever, stress, or certain medications. Low levels generally suggest reduced inflammation, though they don’t always mean you’re healthy.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure CRP levels using a specialized immunoassay method.

What Should You Expect Before the Test?

No special preparation is needed, but inform your doctor about any medications you’re taking, as some may affect results. Avoid strenuous activity 24 hours before the test if instructed.

Reference range

Normal: <3.0 mg/LN/A

Specimen: serum

No special preparation required. CRP may be affected by acute illness.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is a non-specific marker of inflammation. High levels can signal infections, autoimmune diseases, or other inflammatory conditions. It’s often used alongside other tests to guide treatment decisions, but it’s not diagnostic on its own.

Short name

CRP (Serum/Plasma)

Frequently asked questions

How long does it take to get my CRP test results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Follow-up with your healthcare provider to discuss the meaning of your results.
Can diet or exercise affect CRP levels?
Dietary factors like a healthy, anti-inflammatory diet may influence CRP levels over time, but short-term changes are less predictable. Exercise can lower CRP in some people, but results vary.
What if my CRP level is outside the normal range?
If your CRP level is elevated, your doctor may recommend further testing or adjustments to your treatment plan. If it’s low, they may still want to monitor inflammation closely, especially if you have a condition linked to it.
  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