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C-reactive protein (CRP) concentration, serum/plasma

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

This test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation in your body.

Quick summary

CRP helps doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases.

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

Key facts at a glance

LOINC
90096-9
Short code
EVENTMANAGINGGROUPATCOLEADDEPARTMENTORAGENCY
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86038
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 healthcare provider may order a CRP test to check for signs of inflammation, monitor chronic conditions (such as arthritis or heart disease), or evaluate responses to treatments. It can also help diagnose infections or identify risks for certain health issues.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it’s done on an empty stomach, but this depends on the lab’s protocol. Bring any medications you’re taking to your appointment.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a brief pinch or discomfort, but it usually lasts only a few seconds. The process takes about 5 minutes.

What Are Possible Results?

Results are typically reported in milligrams per liter (mg/L). Higher than normal levels may indicate inflammation, infection, or other health concerns, while lower levels may suggest reduced inflammation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP is a marker for inflammation and can reflect underlying health issues like infections, autoimmune diseases, or cardiovascular risks. Elevated CRP may prompt further testing or adjustments to treatment plans.

Short name

CRP (Serum/Plasma)

Frequently asked questions

What does a high CRP level mean?
A high CRP level often signals inflammation in your body, which can be caused by infections, injuries, or conditions like arthritis or heart disease. Your doctor will discuss the results with you and may recommend additional tests or treatments.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a balanced diet, staying active, and managing stress may help lower inflammation over time.
Is CRP the same as a white blood cell count?
No, CRP measures a specific protein linked to inflammation, while a white blood cell count assesses the number of immune cells in your blood. Both tests serve different purposes in diagnosing health conditions.
  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