University of Iowa
Diagnostic Laboratories
(UIDL) Test Directory

319-384-7212 (local)
1-866-844-2522 (toll free)


C-Reactive Protein (CRP) Order Code: CRP
Order Form: Laboratory Requisition
Specimen:
Plasma
Collection Medium:
Plasma separator tube
Alternate
Collection Media:
Call laboratory for additional acceptable specimen collection 
containers.
Minimum:
2 ml whole blood from light gr een top tube or 1 light green microtube 
for pediatric patients
Testing
Schedule:
24 hrs/day, 7 days a week, including holidays.
Analytic Time:
1 hour (upon receipt in laboratory)
Reference Range:
<0.5 mg/dl
Test
Limitations:
Criterion: Recovery within plus or minus 10% of initial values.

Icterus: No significant interference up to an I index of 60 
(approximate conjugated and unconjugated bilirubin concentration: 60 
mg/dl or 1026 umol/l).

Hemolysis: No significant interference up to an H index of 700. 
(approximate hemoglobin concentration: 700 mg/dl or 435 umol/l )

Lipemia (Intralipid): No significant interference up to an L index of 
1000 (approximate triglyceride concentration: 2000 mg/dl or 22.8 
mmol/l).
There is poor correlation between turbidity and triglyceride 
concentration.

Rheumatoid factors less than 1200 IU/ml do not interfere.

A high-dose hook effect may occur at CRP concentrations greater than 50 
mg/dl.
Methodology:
Immunoturbidometric
Sample
Processing:
Centrifuge at 3000 RPM for 10 minutes.
Aliquot plasma into labeled container and cap.
Sample
Storage:
Refrigerate.
Transport
Instructions:
Place specimen into zip-lock type bag, seal bag.
Place requisition into outside pocket of bag.
Transport in cooler with refrigerated coolant packs.
CPT Code:
86140

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Updated: 05/05/2005