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HelpTest Code CRPHS CRP, High Sensitivity (CHD Risk)
Useful For
This test is useful for assessing atherosclerosis/cardiovascular risk in apparently healthy adults. Because CRP is an acute phase reactant and shows significant elevations in inflammatory states, this test should not be used for acutely ill patients. It is essential that the patient be in a stable, basal state prior to assessment. Repeat testing may be required to confirm a basal CRP level. For evaluating inflammatory states, the routine CRP assay should be used which is available on a 24-hour basis.
Synonyms/Keywords
CRP, High Sensitivity C-Reactive Protein, Ultrasensitive CRP
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Serum | Red Top Tube (RTT) | Serum Separator Tube (SST) | 0.5 mL | 0.4 mL | 0.3 mL |
Collection/Processing Instructions
Samples should be centrifuged and serum removed within two hours of collection.
Repeated freeze/thaw cycles should be avoided. Specimens that are very lipemic (3+) or that are turbid from freezing need to be clarified by centrifuging for 10 minutes at approximately 15,000 x g prior to testing.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerate | 7 days |
| Frozen | 3 months |
Rejection Criteria
Plasma samples
Interferences
In very rare cases gammopathy, especially monoclonal IgM (Waldenstroms macroglobulinemia), may cause unreliable results.
Samples containing heterophilic antibodies can cause falsely elevated results. Please note that oral contraceptives have been reported to affect results.
Interpretations
C-Reactive Protein (CRP) has long been used as a sensitive marker of acute inflammation. More recent studies suggest however that subtle changes in CRP levels within the traditional normal range are indicative of inflammatory processes that may play a role in the atherosclerotic plaque formation. Assays capable of measuring these low levels are referred to as "high-sensitivity CRP". These batch assays generally provide an order of magnitude greater sensitivity enabling two decimal place reporting within the normal range of 0 - 1 mg/dL, compared to the routine rapid-turnaround assays for large acute changes in the 0 - 15 mg/dL range.
C-Reactive Protein is an acute phase reactant. Elevated results (>10.0 mg/L by the high-sensitivity assay) may suggest an inflammatory condition and should be repeated after a minimum of several weeks to assure that the patient is in a basal condition.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| Marshfield |
Currently, units are in mg/L and cutoffs are per the CDC/AHA consensus Guidelines published in Circulation 2003 (Jan 28); 107:499-511.
<1.0 mg/L: Low Cardiovascular Risk 1.0-3.0 mg/L: Average Risk >3.0 mg/L: High Risk (2 fold higher than low risk group) >10.0 mg/L: Suggests inflammation (repeat when basal) |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield |
Monday through Friday at 0900
Samples received in the laboratory section after 0900 will be run on the next business day. |
6-8 hours | Turbidimetric method/Beckman AU680 |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 86141 |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 86141 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | CRP, High Sensitivity (CHD RISK) |