Skip to content

C-reactive protein (CRP) by high-performance liquid chromatography (HPLC) or chemiluminescent immunoassay (CLIA)

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

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

Quick summary

["CRP helps track inflammation, which can signal infections, autoimmune conditions, or other health issues."]

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

Key facts at a glance

LOINC
45084-1
Short code
C trach DNA Vag Ql NAA+probe
Synonyms
C trach DNA Vag Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
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 CRP is Used

Doctors may order CRP tests to monitor conditions like infections (e.g., pneumonia, urinary tract infections), inflammatory diseases (e.g., rheumatoid arthritis), or to assess response to treatment. It can also help evaluate risk for heart disease or other chronic conditions.

What to Expect Before the Test

No special preparation is needed, but you may fast for 8–12 hours if your blood is drawn early in the morning. Wear comfortable clothing for an arm puncture. If you’re on blood thinners, let your provider know.

Common Causes of Elevated CRP

High CRP levels can occur with infections (bacterial/viral), injuries, surgeries, or autoimmune diseases. It may also rise with certain cancers or after heart attacks.

What Normal Results Mean

Results alone don’t diagnose a condition—they’re part of a bigger picture. Low CRP usually means minimal inflammation, but doctors compare it to your symptoms and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP

Frequently asked questions

How long does it take to get my CRP results?
Results are typically ready within 24–48 hours, depending on your lab. Follow-up with your provider to discuss next steps.
Can I eat or drink before my CRP test?
If fasting is required, avoid food/drinks (except water) for 8–12 hours before drawing blood. Check with your lab for specifics.
Does CRP change with age?
Yes, CRP levels can vary with age, health status, and medications. Your provider will consider these factors when interpreting results.
  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