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C-Reactive protein, Highly Sensitive, Serum / Plasma

Item Value
Approval req'd? No
Available Stat? No
Test code CRPH
Performed by Immunology
In House Availability Monday, Wednesday, Friday (day shift)
Method Rate Turbidimetry
Container type Gold top preferred, Light green top acceptable
Amount to Collect 1 mL blood
Sample type Serum or plasma
Preferred volume 0.5 mL serum or plasma
Min. Volume 0.3 mL serum or plasma
UCSF Rejection Criteria Lipemic samples
Processing notes Refrigerate
Units mg/L
Normal range
Tertile CRP mg/L Cardiovascular Risk
1 < 1.0 Low
2 1.0-3.0 Moderate
3 > 3.0 High
Synonyms CRPhs; cardiac CRP; cardio CRP
Turn around times 2-5 days
Additional information Lipemia interferes with the assay.

Tertile risk is based on recommendations from the Centers for Disease Control and Prevention and the American Heart Association in Pearson TA, et al. Markers of inflammation and cardiovascular disease. Application to clinical and public health practice. Circulation 107:499-511, 2003.

This assay is alleged to predict an increased risk of cardiovascular and cerebrovascular events in patients with elevated CRP levels relative to "baseline" CRP in patients without these diseases.

Relative risk is approximately 2-4 fold in men and 2-7 fold in women; the level of risk correlates with the degree of CRP elevation. Relative risk of cardiovascular events predicted by CRP determination is independent of serum cholesterol/HDL levels. Patients with elevated total cholesterol/HDL ratios plus higher serum CRP are at further increased risk of cardiovascular events compared to patients with either risk factor alone. Hence these two assays should be used together to determine overall cardiovascular risk.

Risk of ischemic stroke is believed to be best predicted by CRP testing alone.

"Normal" baseline CRP levels are directly related to age, with values of approximately 0.4 mg/L considered normal for ages 20-50 years, while 1.3 mg/L for ages 50-80. Use of this test to predict cardiovascular/stroke risk must be done in context with other clinical parameters.

The absolute relative risk as a function of CRP levels has not been extensively validated. Treatment of patients with elevated CRP levels, using statins and prophylactic ASA, has been shown to reduce cardiovascular risk.

Underlying tumor or inflammatory illness, including drug reactions or infections, may cause CRP elevation unrelated to the risk of cardiovascular disease; specimens should be obtained at least two weeks after the resolution of any acute inflammatory condition.
CPT coding 86141
LOINC code 1988-5
Last Updated 5/29/2016 10:08:48 PM
Entry Number 270
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