Test Details
Methodology
Kinetic
Result Turnaround Time
Within 1 day
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Urine creatinine in mg/dL and mg/24 hours
Use
Renal function test when used as part of creatinine clearance; crude marker for completeness of 24-hour urine collections when collected for other purposes
Special Instructions
Record total 24-hour urine volume on the request form.
Limitations
Complete urine collections require vigilance on the part of nursing personnel. Ingestion of meat may increase creatinine values of urine collections as well as serum creatinine values. Drugs interfering with tubular creatinine secretion include cimetidine, trimethoprim, and probenecid. Creatinine reabsorption occurs with very low urine flow rates. Entities in which reabsorption occurs include severe congestive heart failure, uncontrolled diabetes mellitus, and acute renal failure.1
Custom Additional Information
Urine creatinine is not ordered alone. Creatinine clearance, which requires a serum creatinine, offers useful renal function data. Serum creatinine alone is not an adequate index of glomerular filtration rate.1
Specimen Requirements
Specimen
Urine (24-hour)
Volume
10 mL aliquot of entire collection
Minimum Volume
0.5 mL aliquot (Note: This volume does not allow for repeat testing.)
Container
Plastic urine container, with or without 6N HCl
Collection Instructions
If the specimen is a 24-hour collection instruct the patient to void at 8 AM and discard the specimen. Then collect all urine including the final specimen voided at the end of the 24-hour collection period (ie, 8 AM the next morning). Screw the lid on securely. Transport the specimen promptly to the laboratory. Container must be labeled with patient's full name, date and time collection started, and date and time collection finished.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 7 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Storage Instructions
Room temperature
Causes for Rejection
Times not indicated; improper labeling
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 003012 | Creatinine, 24-Hour Urine | 2162-6 | 013672 | Creatinine, Urine | mg/dL | 2161-8 |
| 003012 | Creatinine, 24-Hour Urine | 2162-6 | 013227 | Creatinine, Ur 24hr | mg/24 hr | 2162-6 |
| Order Code | 003012 | |||||
| Order Code Name | Creatinine, 24-Hour Urine | |||||
| Order Loinc | 2162-6 | |||||
| Result Code | 013672 | |||||
| Result Code Name | Creatinine, Urine | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2161-8 | |||||
| Order Code | 003012 | |||||
| Order Code Name | Creatinine, 24-Hour Urine | |||||
| Order Loinc | 2162-6 | |||||
| Result Code | 013227 | |||||
| Result Code Name | Creatinine, Ur 24hr | |||||
| UofM | mg/24 hr | |||||
| Result LOINC | 2162-6 |