Order Code
3545
Preferred Specimen
Collect 2 mL of serum. Allow the SST (serum separator tube) to clot upright for at least 30 minutes, then centrifuge within 2 hours. Store refrigerated.
ContainerType
Serum separator tube
Alternate Specimen Requirements
Collect 2 mL of serum in a plain red‑top tube. Let the sample clot upright for at least 60 minutes. Then centrifuge, transfer the serum into a plastic transport tube within 2 hours, and clearly label it as “serum from red top tube.” Store refrigerated.
Minimum Volume
Adult: 0.5 mL serum
Pediatric: 0.2 mL serum (does not allow for repeat or
additional testing).
Transport Temperature
Refrigerated
Expected Turnaround Time
1-2 days
Specimen Stability
1 week room temperature;1 week refrigerated; 1 month frozen
Methodology
Roche COBAS particle enhanced immunoturbidimetric gen 4 Note: STAT or regional laboratory testing may use different methodology and/or manufacturer
Rejection Criteria
- Gross hemolysis
Overview
C‑reactive protein (CRP) is an acute phase reactant synthesized in the liver. It begins to rise within hours after the onset of inflammation or tissue injury. While CRP is a highly sensitive marker of inflammation, it is nonspecific. Elevated levels may occur in settings such as acute myocardial infarction, sepsis, malignancy, autoimmune diseases, or post‑surgical inflammation. Epidemiologic studies have also demonstrated associations between baseline CRP and future risk of coronary heart disease (see High-Sensitivity CRP testing).
Clinical Significance
For several decades CRP levels have been used, somewhat like the erythrocyte sedimentation rate (ESR), as a useful marker of inflammation, both for early detection and activity monitoring.
- Nonspecific indicator or inflammation often used in routine laboratory screening of ill patients.
- Aid in detecting infection and assess antibiotic response to bacterial infection
- Postoperative monitoring: Aids in detecting possible complications (inflammation/infection). By 4-6 hours after a surgical procedure the circulating CRP begins to rise and reaches a peak, by 2-3 days after the operation. Postoperative values exceeding this range are associated with significant complications – usually inflammatory processes.
- Useful as a risk factor for cardiovascular disease – epidemiologic studies have established that individuals with a higher baseline CRP are at increased risk for CHD and stroke. See High Sensitivity C-Reactive Protein, Serum or Plasma
- Aid in detecting, assessing severity, and monitoring inflammatory process of many disease processes or conditions including
- Myocardial infarction
- Pelvic inflammatory disease (PID)
- Sepsis in critically ill patients
- Acute appendicitis
- Transplant rejection
Interpretative Information
A threshold <10 mg/L is often proposed as a cutoff for significant inflammatory disease.
Limitations
- Although frequently reflects the presence and intensity of an inflammatory process results are nonspecific and should be interpreted with clinical history; further testing may be warranted.
- Lipemia or hemolysis may give false-positive results.
- Oral contraceptives may falsely elevated CRP levels (van Rooijen, 2006).
References
Gambino R. C-reactive protein – undervalued, underutilized. Clin Chem. 1997;43(11):2017-2018.9365383
Hallan S, Asberg A, and Edna TH. Additional value of biochemical tests in suspected acute appendicitis. Eur J Surg. 1997;163(7):533-538.9248988
American Association for Clinical Chemistry (AACC). Electrolytes and Anion Gap. AACC website. https://labtestsonline.org/tests/aldosterone-and-renin. Updated September 5, 2019. Accessed August 14, 2020.
Ishii S, Karlamangla AS, Bote M, et al. Gender, obesity and repeated elevation of C-reactive protein: data from the CARDIA cohort. PLoS One. 2012;7(4). Epub 2012 Apr 30.22558327
Ledue TB and Rifai N. Preanalytic and analytic sources of variations in C-reactive protein measurement: implications for cardiovascular disease risk assessment,” Clin Chem. 2003; 49(8):1258-1271.12881440
McPherson RA and Pincus MR, Henry’s Clinical Diagnosis and Management by Laboratory Methods, 21st ed, Philadelphia, PA: Saunders, 2007.
Mosca L. C-reactive protein – to screen or not to screen?. N Engl J Med. 2002;347(20):1615-1617.12432050
Pearson TA, Mensah GA, Alexander RW, et al. Markers of inflammation and cardiovascular disease. application to clinical and public health practice. a statement for healthcare professionals from the centers of disease control and prevention and the american heart association. Circulation. 2003;107:499-511.12551878
Povoa P, Almeida E, Moreira P, et al. C-reactive protein as an indicator of sepsis. Intensive Care Med. 1998;24(10):1052-1056.9840239
Relijic M and Gorisek B.C-reactive protein and the treatment of pelvic inflammatory disease. Int J Gynaecol Obstet. 1998;60(2):143-150.9509952
van Rooijen M, Hansson LO, Frostegård J, et al. Treatment with combined oral contraceptives induces a rise in serum C-reactive protein in the absence of a general inflammatory response. J Thromb Haemost. 2006;4(1):77-82.16409455
Visser M, Bouter LM, McQuillan GM, et al. Elevated C-reactive protein levels in overweight and obese odults. JAMA. 1999;282(22):2131-2135.10591334
Test Setup Days
Monday through Friday PM shift
CPT
86140 LOINC: 1988-5
Reference Range
<0.5 MG/DL
| UNIT CODE | UNIT CODE NAME | ANALYTE | GENDER | AGE | REFERENCE RANGE | Units of Measure |
|---|---|---|---|---|---|---|
| 3545 | CRP | CRP | NOT SPECIFIED | ALL | <0.5 | MG/DL |
| 3545 | CRP | CRP | MALE | ALL | <0.5 | MG/DL |
| 3545 | CRP | CRP | FEMALE | ALL | <0.5 | MG/DL |