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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 the liver in response to inflammation in your body.

Quick summary

["CRP helps doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
99402-0
Short code
CD19CD79b
Synonyms
Cells.CD19+CD79b+ NFr Mar
Category
chemistry
Sample
serum
Container
Heparinized bone marrow aspirate collected in sodium heparin (green-top) or EDTA (purple-top) tube for flow cytometry; sterile collection tube preferred for tissue culture if applicable
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Multiparametric Flow Cytometry (Immunophenotyping) using fluorescently labeled monoclonal antibodies against CD19 and CD79b surface markers, typically performed on fresh bone marrow aspirate specimens with CD45 vs. side-scatter gating strategy
CPT
88184
SNOMED
40970007
Specimen volume
1-3 mL of bone marrow aspirate (first draw preferred to avoid peripheral blood dilution)
Stability
Specimen should be processed within 24-48 hours of collection; keep at room temperature (18-22°C); do not refrigerate or freeze as this may compromise cell viability and surface antigen integrity
Hemolysis max
500
Lipemia max
1000
Icterus max
500
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 chronic conditions like arthritis or heart disease, or evaluate responses to treatments. It can also help diagnose infections or identify risks for conditions like heart disease.

What Does a High or Low Level Mean?

Elevated CRP levels often indicate inflammation, infections, or autoimmune activity. Lower-than-normal levels may suggest reduced inflammation, but they don’t always mean you’re healthy. Always discuss results with your doctor.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s analyzed using nephelometry, a method that measures how much light a protein scatters.

What Should You Do Before the Test?

Avoid strenuous exercise or taking anti-inflammatory medications 24 hours before the test, as these can affect results. Follow any specific instructions your doctor provides.

Reference range

Reference values vary by laboratory and should be interpreted in the context of bone marrow cellularity and clinical findings. B-cell precursors (hematogones) normally express CD19 and CD79b; mature B-cells comprise a minor fraction of normal bone marrow. Results expressed as percentage of total nucleated cells or absolute count.N/A

Specimen: serum

No special patient preparation is required. Inform the laboratory of any recent chemotherapy, immunotherapy, rituximab or anti-CD20 therapy, hematopoietic growth factor administration, or transfusion history as these may affect B-cell populations.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Nephelometry)

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing schedule. Your doctor will contact you once they have the results.
What does a normal CRP level mean for my health?
A normal CRP level doesn’t guarantee you’re free of inflammation. It’s one piece of the puzzle. Your doctor will consider other factors, like symptoms, medical history, and test results, to interpret your results accurately.
Can diet or supplements affect CRP levels?
Dietary changes, such as reducing processed foods or increasing omega-3s, may influence inflammation. Some supplements, like fish oil or turmeric, might also affect CRP levels, but results can vary. Always consult your doctor before making changes.
  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