Effective March 9, 2026, urine specimens with creatinine levels below and above the reportable range will be designated as Test Not Performed (TNP). Tests with urine creatinine <0.05 and >16.02mg/mL will be designated as Test Not Performed (TNP) and a retest would be requested. Associated panels will also be marked as TNP due to sample integrity concerns. A one-time courtesy recollection will be provided to the patient for retesting.
Very low urine creatinine is associated with excessively diluted samples, which do not reliably reflect the true biological composition of the specimen. Conversely, very high urine creatinine levels are associated with highly concentrated samples, which may also limit accurate interpretation. All urine samples with creatinine values within the reportable range are processed and included in final reports.
Common Causes of Low or High Urine Creatinine:
- Hydration Status: Excessive fluid intake prior to sample collection may result in low urine creatinine due to dilution, while dehydration may result in elevated urine creatinine due to concentration.
- Variability in Creatinine Production: Differences in muscle mass, age, and certain dietary patterns can contribute to variation in urine creatinine levels.
- Sample Collection: Incomplete or improperly performed collection.
- Medical Conditions: Low urine creatinine can result from certain medical conditions affecting kidney function and creatinine excretion.
Reportable Range: Reportable range refers to the range of values that a laboratory test can accurately and reliably measure and confidently report for a patient sample. The reportable range differs from the reference range and limits of detection. For urine creatinine, the reportable range is 0.05-16.02 mg/mL. All tests with urine creatinine between 0.05-16.02 mg/mL will be processed and included in the final patient reports.
Collection and Test Preparation Instructions: Vibrant recommends patients follow proper collection and test preparation instructions to help ensure adequate sample quality.