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C-reactive protein (CRP) by nephelometry or turbidimetry

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

This test measures the level of C-reactive protein, a protein produced by your liver in response to inflammation in your body. It helps doctors assess whether you have an inflammatory condition or infection.

Quick summary

["CRP helps track inflammation, guiding treatment decisions and monitoring recovery."]

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

Key facts at a glance

LOINC
106954-1
Short code
BMCD123CD19FC
Synonyms
Cells.CD123+CD19+ NFr Mar FC
Category
chemistry
Sample
serum
Container
Bone marrow aspirate collected into sterile tubes containing anticoagulant (heparin or EDTA) for flow cytometry; sodium heparin is preferred for immunophenotyping to preserve cell viability and antigen expression
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
88184
SNOMED
445529007
Specimen volume
1-3 mL of bone marrow aspirate (first draw preferred to avoid hemodilution); minimum 0.5 mL acceptable for flow cytometry analysis
Stability
Specimen should be delivered to the laboratory immediately and processed within 24 hours of collection. Store at room temperature (18-25°C). Do not refrigerate or freeze. Viability and antigen expression decrease significantly after 24 hours.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–48 hours
Order
routine

Why CRP Matters in Your Health

C-reactive protein (CRP) is a marker your body uses to signal inflammation. It rises when tissues are damaged, infections occur, or autoimmune diseases are active. This test is often used alongside other tests to diagnose conditions like infections, heart disease, or inflammatory disorders.

Common Uses for CRP Testing

Doctors may order CRP tests to check for signs of inflammation in conditions such as rheumatoid arthritis, lupus, or after surgery to monitor healing. It can also help evaluate heart health, especially in people at risk for cardiovascular disease.

How CRP Levels Are Interpreted

CRP levels can vary widely depending on your health status. While reference ranges differ by lab, higher-than-normal levels may indicate inflammation or infection, while very low levels might suggest no active inflammation. Your doctor will interpret results in the context of your medical history and other tests.

What to Expect During the Test

This test typically involves drawing blood from a vein in your arm. The sample is sent to a lab, where it is analyzed using either nephelometry (measuring light scattering) or turbidimetry (measuring cloudiness). Results are usually available within 24 to 48 hours.

Reference range

Reported as percentage of total nucleated bone marrow cells. Reference ranges are laboratory-specific and should be interpreted in conjunction with morphological and clinical findings. CD123+/CD19+ cells are typically rare in normal bone marrow; results are generally reported qualitatively or as a percentage with comparison to institutional reference data.N/A

Specimen: serum

Bone marrow aspiration is performed by a qualified physician under local anesthesia (and sedation if indicated). No specific fasting is required prior to bone marrow aspiration. Informed consent must be obtained. Patient should inform the clinician of anticoagulant use, bleeding disorders, allergies to anesthetics, and current medications prior to the procedure.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP Level

Frequently asked questions

How often should I get a CRP test?
CRP tests are often ordered as part of routine check-ups, especially if you have risk factors for inflammation or chronic conditions like heart disease or arthritis. Your doctor will determine how frequently you need testing based on your health needs and symptoms.
What causes CRP levels to be high?
High CRP levels can be caused by infections (like pneumonia or urinary tract infections), autoimmune diseases (such as rheumatoid arthritis or lupus), injuries, surgeries, or other inflammatory conditions. Stress, smoking, and certain medications can also influence CRP levels.
Can CRP levels be affected by diet or lifestyle?
Yes, lifestyle factors like diet, exercise, smoking, and stress can influence CRP levels. A healthy diet rich in fruits, vegetables, and omega-3 fatty acids may help lower inflammation, while smoking and sedentary behavior can raise CRP 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