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Serum or plasma concentration of **C-reactive protein** (CRP) measured by nephelometry

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

This test measures the amount of C-reactive protein in your blood, a protein produced by your liver in response to inflammation or infection.

Quick summary

["CRP helps track inflammation, often used to monitor conditions like infections, autoimmune diseases, or post-surgery healing."]

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

Key facts at a glance

LOINC
82937-4
Short code
SAP + XIAP WBC FC-Imp
Synonyms
SAP + XIAP WBC FC-Imp
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
85004
SNOMED
900000000000003002
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 CRP Matters in Your Health

CRP is a marker that signals your body’s immune response. High levels may indicate inflammation, infections (such as pneumonia or urinary tract infections), or conditions like rheumatoid arthritis or heart disease. It’s also used to assess how well treatments are working for certain conditions.

When This Test Is Ordered

Doctors may order CRP tests to diagnose or monitor conditions like infections, autoimmune diseases, or to check for signs of inflammation before or after surgery. It can also help evaluate heart health or response to treatments for chronic illnesses.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader metabolic or liver panel. Bring any medications you’re taking, as some may affect results.

What to Expect During the Test

A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but it’s quick and painless. The blood sample is then sent to a lab for analysis.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP Level

Frequently asked questions

What does a high CRP level mean?
A high CRP level suggests inflammation or infection in your body. Your doctor may recommend further testing or treatments to address the underlying cause, such as antibiotics for infections or medications for autoimmune conditions.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. Eating a heart-healthy diet, staying active, and avoiding smoking may help lower inflammation over time.
Is CRP the same as a white blood cell count?
No, CRP is a specific protein marker for inflammation, while a white blood cell count measures the total number of immune cells in your blood. Both tests can be used together to assess health, but they provide different information.
  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