C-reactive protein (CRP) with plasma concentration measurement
This test measures the level of C-reactive protein in your blood plasma, a marker often checked for signs of inflammation or infection.
["CRP helps track inflammation, guiding decisions about treatment or further testing."]
Key facts at a glance
- LOINC
- 107043-2
- Short code
- CD3CD4CD8DP
- Synonyms
- CD3+CD4+CD8+ NFr Spec FC
- Category
- chemistry
- Sample
- serum
- Container
- Heparin (sodium or lithium heparin) anticoagulant tube — green-top tube; EDTA (purple-top) is acceptable for some flow cytometry platforms; ACD-A tubes may also be used
- Units
- N/A
- Ref low
- 0
- Ref high
- 3
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- flow-cytometry
- CPT
- 86359
- SNOMED
- 269773004
- Specimen volume
- 3-5 mL of whole blood; minimum 1 mL for pediatric or limited samples
- Stability
- Specimen should be processed within 24-48 hours of collection when stored at room temperature (18-25°C); do not refrigerate or freeze whole blood as this may affect cell viability and marker expression; if delayed beyond 24 hours, consult laboratory for viability assessment
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–48 hours
- Order
- routine
Why Is This Test Done?
Doctors may order CRP testing to monitor conditions like arthritis, infections, or other inflammatory diseases. It can also help assess how your body is responding to treatment or detect early signs of problems like heart disease or autoimmune disorders.
What Does a High or Low CRP Level Mean?
A higher CRP level often indicates inflammation, but it can also be influenced by factors like fever, stress, or certain medications. A consistently low level may suggest no active inflammation, though it doesn’t rule out all causes.
How Is This Test Performed?
Blood is drawn from a vein, usually in your arm. The plasma portion is separated and analyzed to measure CRP levels using a sensitive immunoassay method.
What Are Common Results and Next Steps?
Results are typically reported in arbitrary units per milliliter (U/mL). If your CRP is elevated, your healthcare provider may recommend further testing or adjustments to your treatment plan.
Reference range
CD3+CD4+CD8+ double-positive T cells are normally rare in peripheral blood, typically representing <3% of total CD3+ T cells or <1% of total lymphocytes in healthy adults. Reference ranges vary by laboratory; results should be interpreted alongside absolute CD3, CD4, CD8, and CD4/CD8 ratio values.N/A
No special patient preparation required. Fasting is not necessary. Recent immunotherapy, corticosteroid use, chemotherapy, or immunosuppressants may affect T-cell subset distribution and should be documented on the requisition. Avoid testing during active severe infection when possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CRP Plasma
Frequently asked questions
What causes CRP levels to change?
How often should I get this test?
Can lifestyle changes affect CRP levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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