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C-reactive protein (CRP) immunoassay, measured by chemiluminescent immunoassay (CLIA) in plasma

Published: August 9, 2026Updated: August 17, 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 identify inflammation, which can be linked to infections, injuries, or other health conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
101345-7
Short code
C krusei DNA Spec Ql NAA+probe
Synonyms
C krusei DNA Spec Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
CPT
82553
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, monitor chronic conditions like arthritis, or evaluate symptoms such as fever, pain, or swelling that suggest infection or other issues.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein in your arm to collect a blood sample. This is usually done in a clinic or lab setting.

What the Results Mean

Higher CRP levels often indicate inflammation. While elevated CRP can signal infections, injuries, or autoimmune diseases, it doesn’t always pinpoint the exact cause. Your doctor will interpret results in the context of your symptoms and medical history.

Common Conditions Monitored

Elevated CRP levels are commonly monitored in conditions like rheumatoid arthritis, heart disease, infections (such as pneumonia or sepsis), and other inflammatory diseases. It can also be used to track response to treatment.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Plasma) CLIA

Frequently asked questions

What does a high CRP level mean?
A high CRP level suggests inflammation is present in your body. It can be due to infections, injuries, autoimmune diseases, or other health issues. Your doctor will consider your symptoms and other test results to determine the cause.
How often should I get this test?
Your doctor will decide how often to check your CRP levels based on your medical needs. Some people may need it regularly if they have chronic conditions like arthritis or heart disease, while others may only need it occasionally.
Can lifestyle changes affect CRP levels?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. Reducing inflammation through healthy habits may help lower CRP levels, but results depend on the underlying cause of your inflammation.
  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 17, 2026. · Read our editorial policy