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C-reactive protein (CRP) by nephelometry

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

This test measures the level of C-reactive protein, a protein produced by your body in response to inflammation.

Quick summary

["CRP helps doctors assess inflammation in your body."]

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

Key facts at a glance

LOINC
106945-9
Short code
CD26CD3BM
Synonyms
Cells.CD26+CD3+ NFr Mar FC
Category
chemistry
Sample
serum
Container
Bone marrow aspirate collected into sterile anticoagulant tubes (EDTA or heparin) for flow cytometric analysis
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
88184
SNOMED
396450007
Specimen volume
1-3 mL of fresh bone marrow aspirate in anticoagulant tube; first pull (aspiration 1) preferred for accurate assessment
Stability
Specimen should be processed within 24 hours of collection when stored at room temperature (18-25°C). Refrigeration (2-8°C) may extend viability up to 48 hours but cell viability may decline. Do not freeze.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–48 hours
Order
routine

What Is C-Reactive Protein?

C-reactive protein (CRP) is a marker that your immune system produces when it detects inflammation. It can rise in response to infections, injuries, or other conditions that trigger inflammation, such as autoimmune diseases or certain chronic health issues. CRP doesn’t specifically identify the cause of inflammation but helps track how active it is in your body.

Why Might Your Doctor Order This Test?

Your doctor may order CRP testing to monitor inflammation, especially if you have conditions like rheumatoid arthritis, heart disease, or other inflammatory disorders. It can also be used to check for infections, track treatment responses, or assess risk for conditions like heart disease before symptoms appear.

How Is This Test Done?

A small blood sample is drawn from a vein, usually in your arm. The blood is then sent to a lab where it is analyzed using nephelometry, a method that measures how much CRP is present in your serum or plasma.

What Does a High or Low CRP Level Mean?

High CRP levels often signal inflammation, but they don’t pinpoint the exact cause. Very high levels may indicate infections, severe inflammation, or conditions like sepsis. Low or normal levels suggest minimal inflammation, but they don’t rule out all causes of inflammation.

Reference range

CD26+CD3+ cells in bone marrow typically represent a subset of activated T lymphocytes. Reference ranges vary by laboratory; results are generally reported as percentage of total cells or absolute count. Clinical interpretation should be performed by a qualified hematopathologist in conjunction with morphology and other immunophenotypic findings.N/A

Specimen: serum

No special patient preparation required. Bone marrow aspiration is performed by a qualified physician under local anesthesia (with or without sedation). Informed consent must be obtained prior to the procedure. Patients on anticoagulants should be evaluated for bleeding risk prior to bone marrow sampling.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP

Frequently asked questions

What could cause my CRP levels to be higher than expected?
Several factors can increase CRP levels, including infections (like colds or flu), injuries, surgeries, certain medications, or underlying conditions like autoimmune diseases. Stress, smoking, and obesity may also play a role. If your CRP is elevated, your doctor may investigate these causes further.
How often should I get this test?
The frequency depends on your health condition and why the test was ordered. Some people get CRP tests yearly to monitor chronic inflammation, while others may need them more often if they have ongoing health concerns or treatments.
Can I do anything to lower my CRP levels?
Yes! Lifestyle changes like improving diet (eating more fruits, vegetables, and whole grains), staying physically active, managing stress, quitting smoking, and maintaining a healthy weight can help reduce inflammation. If you have a known cause for elevated CRP, treating that condition may also lower your levels.
  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