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HelpTest ID CRBF Creatinine, Body Fluid
Useful For
Identifying the presence of urine as a cause for accumulation of fluid in a body compartment
Method Name
Enzymatic Colorimetric Assay
Reporting Name
Creatinine, BFSpecimen Type
Body FluidContainer/Tube: Sterile container
Specimen Volume: 1 mL
Collection Instructions: Centrifuge to remove any cellular material.
Additional Information: Indicate specimen source.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Body Fluid | Refrigerated (preferred) | 7 days |
| Frozen | 90 days |
Clinical Information
By-products of nitrogen metabolism are elevated in high concentration in urine compared to blood, and serve as a surrogate marker for the identification of urine leakage into a body compartment. This may occur due to trauma, abdominal or pelvic surgery, and bladder perforation. (1,2) Concentrations of creatinine or urea nitrogen that exceed the concentration found in a concurrent sample of blood are suggestive of the presence of urine.(1,3)
Reference Values
Not applicable
Cautions
Specimens with total bilirubin values >20 mg/dL may see decreased values. Protein, glucose, ascorbic acid, a-ketoacids, and some cephalosporin antibiotics may interfere with the creatinine assay, causing an overestimation.
Results can be falsely decreased in patients with elevated levels of N-acetyl-p-benzoquinone imine (NAPQI, a metabolite of acetaminophen), N-acetylcysteine (NAC), and Metamizole.
Day(s) Performed
Monday through Sunday; Continuously
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been modified from the manufacturer’s instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
82570