C-Reactive Protein (CRP) Test
The C-reactive protein (CRP) test is a blood test that measures the level of CRP, a protein produced by the liver, in the bloodstream.
What is C-Reactive Protein?
C-reactive protein (CRP) is an acute-phase reactant, a type of protein that increases in response to inflammation or infection. It is produced by the liver and released into the bloodstream in response to tissue damage or inflammation.
Purpose of the CRP Test
The CRP test is used to:
- Detect and monitor inflammatory conditions, such as arthritis, autoimmune disorders, and infections
- Evaluate the severity of an infection or inflammation
- Monitor the effectiveness of treatment for inflammatory conditions
- Assess the risk of cardiovascular disease, as high levels of CRP have been linked to an increased risk of heart attack and stroke
How is the CRP Test Performed?
The CRP test involves a blood sample being taken from a vein in the arm. The blood sample is then sent to a laboratory for analysis.
Interpretation of Results
The results of the CRP test are measured in milligrams per liter (mg/L) or milligrams per deciliter (mg/dL). The normal range for CRP is typically less than 10 mg/L, but this can vary depending on the laboratory and the individual.
- Low levels of CRP (<10 mg/L): indicates a low level of inflammation
- Moderate levels of CRP (10-50 mg/L): indicates a moderate level of inflammation
- High levels of CRP (>50 mg/L): indicates a high level of inflammation, which may be indicative of an underlying condition such as infection or autoimmune disorder
Types of CRP Tests
There are two types of CRP tests:
- Standard CRP test: measures the level of CRP in the bloodstream and is used to detect and monitor inflammatory conditions
- High-sensitivity CRP (hs-CRP) test: measures very low levels of CRP and is used to assess the risk of cardiovascular disease
Risks and Limitations
The CRP test is a relatively safe and simple procedure, but there are some risks and limitations to consider:
- Bleeding or bruising at the needle site
- Infection at the needle site
- False-positive results due to other conditions that can cause elevated CRP levels, such as pregnancy or obesity
- False-negative results due to certain medications or underlying medical conditions
Conclusion
The C-reactive protein (CRP) test is a valuable tool for detecting and monitoring inflammatory conditions, evaluating the severity of an infection or inflammation, and assessing the risk of cardiovascular disease. However, it should be used in conjunction with other diagnostic tests and medical evaluations to ensure accurate diagnosis and treatment.
Frequently Asked Questions (FAQs)
What is a C-reactive protein (CRP) test? 
A blood test that measures the level of C-reactive protein in the body. 
 
What is C-reactive protein (CRP)? 
A protein produced by the liver in response to inflammation or infection. 
 
Why is the CRP test ordered? 
To help diagnose and monitor conditions such as infections, inflammatory diseases, and cardiovascular disease. 
 
What are normal CRP levels? 
Typically less than 10 mg/L, but can vary depending on the laboratory and individual. 
 
What do high CRP levels indicate? 
May indicate inflammation, infection, or other conditions, but results should be interpreted by a healthcare professional. 
 
How is the CRP test performed? 
A blood sample is taken from a vein in the arm and sent to a laboratory for analysis. 
 
Are there different types of CRP tests? 
Yes, including high-sensitivity CRP (hs-CRP) tests, which can detect lower levels of CRP. 
 
What factors can affect CRP test results? 
Various factors, including certain medications, medical conditions, and lifestyle habits, may influence CRP levels. 
 
Is the CRP test a definitive diagnostic tool? 
No, results should be considered in conjunction with other diagnostic tests and medical evaluations. 
 
Are there any risks or side effects associated with the CRP test? 
Generally, the blood draw is a low-risk procedure, but may cause minor discomfort or bruising. 
Article last updated on: 18th October 2025.
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