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C-reactive protein (CRP) immunoassay, plasma concentration (quantitative)

Published: August 9, 2026Updated: August 17, 2026

This test measures the level of C-reactive protein in your blood plasma, a marker often used to assess inflammation or infection.

Quick summary

["CRP helps track inflammation, guiding decisions about treatments or further testing."]

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

Key facts at a glance

LOINC
92797-0
Short code
C krusei DNA Bld Pos Ql NAA+probe
Synonyms
C krusei DNA Bld Pos Ql NAA+probe
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
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
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test to check for signs of inflammation, infection, or other conditions like autoimmune diseases, heart disease, or kidney problems. It can also help monitor how well a treatment is working or if symptoms are improving.

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 involves drawing blood from a vein, but CRP plasma tests are often done on any blood sample. Avoid strenuous activity or recent infections before testing if instructed.

How the Test Works

Blood is drawn from a vein (usually in your arm) and sent to a lab. The lab uses an immunoassay method to detect and measure CRP levels in plasma. This test provides a quantitative measurement of CRP concentration.

Possible Results and Interpretation

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

Reference range

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

Specimen: whole-blood

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

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP Plasma

Frequently asked questions

What does a high CRP level mean?
A high CRP level often signals inflammation in the body, which can be caused by infections (like pneumonia or urinary tract infections), autoimmune diseases (like rheumatoid arthritis), or conditions like heart disease or kidney problems. It can also be elevated after surgery or trauma. Your provider will use these results alongside other tests and symptoms to guide diagnosis and treatment.
What does a low CRP level mean?
A low CRP level usually means there is less inflammation in your body. However, it doesn’t rule out all causes of illness. If you’re concerned about symptoms, discuss them with your provider, as other factors may be at play.
How often should I get this test?
Your provider will determine how often you need this test based on your health condition, symptoms, and treatment plan. Regular monitoring may be needed if you have chronic conditions like heart disease or autoimmune disorders.
  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