Lab Test

C Reactive Protein (CRP)

CRP, C-Reactive Protein (CRP)

Test Codes

Antrim #30265, EPIC: LAB6453, CRP



Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)

Physician Office/Draw Specimen Preparation

Let specimen clot 30 – 60 minutes then immediately centrifuge to separate serum from cells within two hours of collection. Refrigerated (2 – 8°C or 36 – 46°F) the centrifuged collection tube within 2 – 4 hours of collection. (Minimum Serum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2 – 8°C or 36 – 46°F). (Minimum Serum: 0.5 mL)

Rejection Criteria

Severely lipemic specimens.

Grossly hemolyzed specimens.

In-Lab Processing

Let specimen clot 30 – 60 minutes then immediately centrifuge to separate serum from cells within two hours of collection. Deliver immediately to the appropriate testing station.


Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gels
Room Temperature (20 – 26°C or 68 – 78.8°F): 24 hours
Refrigerated (2 – 8°C or 36 – 46°F): 7 days
Frozen (-20°C / -4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2 – 8°C or 36 – 46°F): 7 days


Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Chemistry Laboratory
Taylor Chemistry Laboratory
Troy Chemistry Laboratory 


Sunday – Saturday, 24 hours a day.
Routine results available within 4 hours of receipt in the Laboratory.

Reference Range

Less than 8.0 mg/L.

Test Methodology

Farmington Hills:  Turbidometric.
Grosse Pointe:
Royal Oak and Troy:  Latex Enhanced Immunoturbidimetric.


Increased CRP is seen in acute inflammatory conditions.

Half Life in Blood:  5 – 7 hours.

Clinical Utility

C-reactive protein (CRP) is an acute phase reactant and is used as a sensitive and quantitative measure of the body's acute phase response. CRP is not diagnostic for any specific disease. Increased CRP levels are consistently found in patients with acute bacterial and viral infections, rheumatoid arthritis, acute myocardial infarction, and widespread malignant disease. CRP levels respond to inflammation within 8 hours of onset and peak levels are reached within 24-48 hours. Levels may rise to 2000 times normal levels.

CRP levels associated with viral infection, rheumatoid arthritis, and neoplasia are usually 1 – 4 mg/dL. CRP levels of 4 to greater than 30 mg/dL are usually associated with acute bacterial infections.

Monitoring serum CRP levels aids in the detection and evaluation of post-operative complications associated with inflammation and/ or tissue necrosis. CRP levels evaluated 48 – 72 hours postoperatively may be 25 – 35 mg/dL. These levels return to normal within one week.

CPT Codes

LOINC: 1988-5


Last Updated


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