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Creatinine, 24 hour (or timed) urine

Item Value
Test Update Information Effective November 16, 2016, the UCSF Clinical Labs switched to an enzymatic creatinine assay.
Available Stat? Yes
Test code CRU
Test group Creatinine
Performed by Parnassus & Mission Bay Chemistry
In House Availability Test available 7 days per week from 8:00 AM to midnight only.
Method Enzymatic assay on Beckman DXC 600/800 analyzers. Calibration traceable to isotope dilution mass spec (IDMS) standardization

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Collection Instructions Include the patient's weight in kg on the request slip.

Note that the minimum acceptable time period for a 'timed' collection is 6 hours.

Results of collections of less than 24 hour duration will be adjusted to reflect a '24 hour collection'. The limited time of collection as well as the need to adjust the values to be comparable to the '24 hour' normal ranges will inherently affect the accuracy of the results.
Container type 24 hour urine collection container

Click here for Urine Preservative Requirements
Amount to Collect Entire urine output during collection period
Sample type Timed urine collection
Preferred volume 1 mL urine
Min. Volume 0.2 mL urine
Units mg/kg/D
Normal range Age (years):
< 1 8-20 mg/kg/D
1-11 8-22 mg/kg/D
12-15 8-30 mg/kg/D
Male 16-89 years 14-26 mg/kg/D
Female 16-89 years 11-20 mg/kg/D
> 90 years > 9 mg/kg/D


Reference ranges adopted from Tietz Fundamentals of Clinical Chemistry, 5th Edition
Stability Refrigerated 2 days
Turn around times STAT 1 hour, Routine 4 hours
Additional information To convert mg/kg/d to µmol/kg/d (SI units) multiply by 8.84. Output varies with the diet and weight.

Results of collections of less than 24 hour duration will be adjusted to reflect a '24 hour collection'. The limited time of collection as well as the need to adjust the values to be comparable to the '24 hour' normal ranges will inherently affect the accuracy of the results.
CPT coding 82570
Last Updated 11/16/2016 8:23:53 AM
Entry Number 266
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