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C-reactive protein (CRP) with high-sensitivity measurement

Published: August 9, 2026Updated: August 17, 2026

This test measures a protein in your blood that rises when your body is responding to inflammation, often used to check for signs of infection or inflammation.

Quick summary

["hs-CRP helps track subtle inflammation that may not show up in other tests."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
55774-4
Short code
DAT C3d-Sp Reag RBC Ql
Synonyms
DAT C3d-Sp Reag RBC Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why hs-CRP is Done

Doctors may order this test to monitor chronic conditions like heart disease, arthritis, or autoimmune disorders. It’s also used to assess risk for future health issues, such as heart attacks or strokes, especially in people with no obvious symptoms of inflammation.

How It Works

A small blood sample is taken from your arm. The lab uses a sensitive method to detect tiny amounts of CRP, which can be present even when inflammation is mild.

What to Expect Before the Test

No special preparation is needed, but let your doctor know if you’re taking blood thinners or have a history of bleeding disorders. Avoid strenuous activity 24 hours before the test if your doctor recommends it.

What the Results Mean

Results are reported in milligrams per liter (mg/L). Higher levels may indicate inflammation, infection, or other health concerns. Your doctor will interpret the results in the context of your overall health and symptoms.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

hs-CRP

Frequently asked questions

What causes hs-CRP levels to change?
hs-CRP levels can rise due to infections (like colds or urinary tract infections), injuries, surgeries, or certain medications. They may also be elevated in people with conditions like heart disease, diabetes, or obesity. Lifestyle factors like smoking, poor diet, or lack of exercise can also influence results.
How often should I get this test?
Your doctor will determine how often you need this test based on your health status. Some people get it yearly to monitor long-term risk, while others may need it more frequently if they have a history of inflammation or heart disease.
Can lifestyle changes lower my hs-CRP levels?
Yes! Small changes like eating a heart-healthy diet, exercising regularly, quitting smoking, and managing stress can help lower CRP levels. Ask your doctor about specific strategies tailored to your needs.
  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 17, 2026. · Read our editorial policy