Skip to content

C-reactive protein (CRP) concentration in serum/plasma

Published: August 9, 2026Updated: August 16, 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 doctors assess inflammation, often used to monitor conditions like infections, autoimmune diseases, or heart disease."]

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

Key facts at a glance

LOINC
98957-4
Short code
C immitis IgG Spec IA-aCnc
Synonyms
C immitis IgG Spec IA-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
CPT
82784
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 This Test Is Done

Your doctor may order a CRP test to check for signs of inflammation. This could be due to infections (like pneumonia or urinary tract infections), autoimmune conditions (such as rheumatoid arthritis), or to monitor heart health after a procedure or injury. It may also be used to evaluate symptoms like fever, joint pain, or unexplained fatigue.

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 if your doctor specifies it, but this is not always required. Wear a comfortable shirt and bring any medications you’re currently taking.

During the Test

A healthcare provider will insert a small needle into a vein in your arm to draw blood. You may feel a slight pinch, but it usually takes only a few minutes. The blood sample is sent to a lab for analysis.

After the Test

You can resume your normal activities immediately. Apply gentle pressure to the site to stop any bleeding, and check the area for bruising or swelling. Avoid heavy lifting or strenuous activity for a short time if instructed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

How long does it take to get my results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you directly with the results and any follow-up steps.
Can I eat or drink before this test?
Most CRP tests don’t require fasting, but always follow your doctor’s instructions. If fasting is needed, avoid caffeine or heavy meals for the specified period to ensure accurate results.
What does a low CRP level mean?
Low CRP levels usually mean minimal inflammation in your body. However, very low levels might raise concerns if you’re not experiencing symptoms of inflammation, so discuss your results with your doctor.
  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