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C-reactive protein (CRP) by nephelometry

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

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

Quick summary

CRP helps doctors track inflammation, infection, or other health issues.

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

Key facts at a glance

LOINC
96325-6
Short code
M catarrhls DNA L resp NAA+non-prb-NCncRng
Synonyms
M catarrhls DNA L resp NAA+non-prb-NCncRng
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
non-probe-amp-tar
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 this test to check for signs of inflammation, infection, or other conditions like heart disease, autoimmune disorders, or after surgery to monitor healing. It can also help diagnose or manage conditions like rheumatoid arthritis, lupus, or kidney disease.

What to Expect Before the Test

No special preparation is needed for this blood test. You may be asked to fast for 8–12 hours before the draw, but this depends on your provider’s instructions. Wear a comfortable shirt with sleeves rolled up.

What Happens During the Test?

A healthcare professional will insert a small needle into a vein in your arm to draw a blood sample. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood is then sent to a lab for analysis.

What Are the Possible Results?

Results are reported in milligrams per deciliter (mg/dL). Higher than normal levels may indicate inflammation, infection, or other health concerns. Your provider will interpret the results in the context of your medical history and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CRP levels often signal inflammation, which can be linked to infections (like pneumonia or urinary tract infections), autoimmune diseases (such as rheumatoid arthritis or lupus), or other conditions like heart disease or cancer. Lower-than-normal levels may suggest reduced inflammation, but they can also occur in healthy individuals. Always discuss results with your doctor.

Short name

CRP (Nephelometry)

Frequently asked questions

What does a high CRP level mean?
A high CRP level may indicate inflammation or infection, but it doesn’t always pinpoint the exact cause. Your doctor will use the results along with other tests and symptoms to guide treatment.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition. Some people get it regularly to monitor chronic inflammation, while others may need it only during illness or after treatment.
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.
  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