C-reactive protein, mass concentration (serum/plasma)
This test measures the level of C-reactive protein, a protein produced by your liver in response to inflammation or infection in your body.
["CRP helps doctors assess inflammation and track conditions like infections, autoimmune diseases, or heart disease."]
Key facts at a glance
- LOINC
- 2038-8
- Short code
- CEASEM
- Synonyms
- CEA Smn-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, wide-mouth, leak-proof plastic container (semen collection cup); do not use latex condoms or lubricants as they may interfere with the assay.
- Units
- N/A
- Ref low
- 0
- Ref high
- 5
- Fasting
- false
- Population
- adult
- Sex
- male
- Age range
- ≥ 18 years
- Method
- Immunoassay (Chemiluminescent or ELISA)
- CPT
- 82378
- SNOMED
- 395128004
- Specimen volume
- Entire ejaculate (typically 1.5-5 mL)
- Stability
- Seminal fluid should be analyzed within 1 hour of collection at room temperature; if delayed, refrigerate at 2-8°C for up to 24 hours. For prolonged storage, freeze at -20°C or below.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What Is C-Reactive Protein Used For?
CRP is primarily used to detect and monitor inflammation. It can help identify infections (such as pneumonia or urinary tract infections) and evaluate conditions like rheumatoid arthritis, lupus, or heart disease. Some doctors also use it to check for signs of inflammation after surgery or injury.
How Is the CRP Test Performed?
A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure CRP levels. The test is quick and typically done as part of a routine blood draw.
Why Might My CRP Level Be High?
Elevated CRP levels often signal inflammation, which can be caused by infections, injuries, autoimmune diseases, or chronic conditions like heart disease or arthritis. Your doctor will consider your symptoms and other test results to determine the cause.
What Are Common Causes of Low CRP Levels?
Low CRP levels usually mean there is little to no inflammation in your body. However, very low levels might raise concerns if you have a known inflammatory condition, as they could indicate poor treatment response or underlying issues.
Reference range
Non-smokers: <2.5 ng/mL; Smokers: <5.0 ng/mLN/A
Abstain from ejaculation for 2-5 days prior to specimen collection. Inform the laboratory of any recent infections, medications, or supplement use.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP in Healthcare
Short name
CRP (Serum/Plasma)
Frequently asked questions
Why do doctors order a CRP test?
What does a CRP test tell me about my health?
How often should I get a CRP test?
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