C-reactive protein (CRP) mass concentration in serumMedically reviewed by WellAlly Editorial Team·Last reviewed August 16, 2026·[Editorial policy](https://wellally.tech/editorial-policy)
## Key facts at a glance
LOINC76485-2Short codeCRP SerPl-sCncSynonymsCRP SerPl-sCncCategorychemistrySampleserumContainerRed-top tube (SST)UnitsN/ARef low0Ref high3FastingfalsePopulationadultSexallAge range18–65 yearsCPT86140Specimen volume5 mLStabilityRoom temperature: 4h, Refrigerated: 24h, Frozen: 7dHemolysis max500Lipemia max1000Icterus max500TAT4–24 hoursOrderroutine
## Why Is This Test Done?


Your healthcare provider may order this test to check for signs of inflammation, monitor conditions like infections, autoimmune diseases, or heart disease, or evaluate responses to treatments. It can also be used as a general screening tool for overall health.


## What Does a High or Low CRP Level Mean?


A higher than normal CRP level often indicates inflammation, which can be linked to infections, injuries, or conditions like arthritis, heart disease, or certain cancers. A very low level may suggest no active inflammation, though it doesn’t rule out all causes.


## How Is This Test Performed?


A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum (the liquid part without clots) for testing. The CRP level is measured using a sensitive laboratory method to detect its presence.


## What Are Common Causes of Abnormal Results?


Increased CRP levels can result from infections (like pneumonia or urinary tract infections), injuries, surgeries, or conditions such as rheumatoid arthritis, lupus, or heart disease. Certain medications or pregnancy may also affect CRP levels.


Reference range


Normal: <3.0 mg/LN/A

Specimen: serum

No special preparation required. CRP may be affected by acute illness.


## Clinical interpretation


How abnormal results are interpreted and what conditions they suggest.


CRP is a useful marker for detecting and monitoring inflammation, but it’s not definitive on its own. Doctors often use it alongside other tests and clinical findings to make a diagnosis or guide treatment decisions.


## Short name


CRP Serum


## Frequently asked questions
What does a CRP test measure?A CRP test measures the concentration of C-reactive protein in your blood serum. This protein is produced by your liver and rises when your body is inflamed or fighting infection.How long does it take to get CRP test results?Results are typically available within 1 to 3 business days, depending on your lab’s processing times. Your healthcare provider will discuss the results with you during your follow-up visit.Can CRP levels change with diet or exercise?While diet and exercise can influence overall health and inflammation, CRP levels are primarily a reflection of your body’s current inflammatory response. They may not change dramatically with short-term lifestyle adjustments alone.
## Sources
3
1. 1MedlinePlus — Laboratory TestsSource
2. 2Lab Tests OnlineSource
3. 3Mayo 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