Skip to content

C-reactive protein (CRP) by nephelometry

Published: August 9, 2026Updated: August 15, 2026

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

Quick summary

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

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
107861-7
Short code
CAROBIGG
Synonyms
Carob IgG Qn IA
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or red-top tube for serum; plasma separator tube (PST) or green-top (lithium heparin) tube for plasma
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Immunoassay
CPT
86001
SNOMED
39513007
Specimen volume
1-2 mL of serum or plasma
Stability
Serum or plasma is stable for 7 days at 2-8°C. For longer storage, freeze at -20°C or below for up to 3 months. Avoid repeated freeze-thaw cycles.
Hemolysis max
100
Lipemia max
100
Icterus max
50
TAT
24–72 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to check for signs of inflammation, monitor conditions like rheumatoid arthritis, heart disease, or infections, or evaluate responses to treatments. It can also help assess risk for certain diseases, such as cardiovascular issues.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a fasting panel. Bring any medications you’re currently taking.

How the Test Works

A blood sample is taken from a vein in your arm. The lab uses nephelometry, a method that measures how much light scatters when CRP binds to antibodies, helping determine its concentration.

What the Results Mean

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

Reference range

Reference ranges are not well established for carob-specific IgG antibodies. Results should be interpreted in conjunction with clinical symptoms and dietary history. Negative or undetectable levels typically indicate no significant sensitization.N/A

Specimen: serum

No special patient preparation is required. Specimen may be collected at any time of day. Patients should continue their normal diet prior to testing unless specifically instructed otherwise by their healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Nephelometry)

Frequently asked questions

What does a high CRP level mean?
A high CRP level often signals inflammation, which can be caused by infections (like pneumonia or urinary tract infections), autoimmune diseases (like lupus or rheumatoid arthritis), or other conditions such as heart disease or cancer. It’s not specific to one disease but can guide further testing or treatment planning.
What does a low CRP level mean?
A low CRP level usually means there’s little to no inflammation in your body. However, it doesn’t rule out all causes of inflammation, so your provider may still recommend additional tests or monitoring.
Can CRP levels change over time?
Yes, CRP levels can fluctuate based on your health status, recent infections, medications, or other factors like stress or exercise. Regular monitoring may be needed if you have a chronic condition or ongoing symptoms.
  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 15, 2026. · Read our editorial policy