Creatinine, Random Urine

For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

UCRR

8459;
Creat Random Ur;

fresh urine

1 mL

Obtain specimen in urine collection cup and transfer 2 mL to a screw-top transport tube.

Screw-top plastic transport tube

Refrigerated

Room Temperature = 2 days
Refrigerated = 6 days
Frozen = 6 months

Incorrect specimen type, insufficient sample volume, improper storage conditions, exceeds specimen stability guidelines, contaminated sample.

24/7
AU

daily

Creatinine is the endproduct of creatine metabolism. Creatine is present primarily in muscle and the amount of creatinine produced is related to total skeletal muscle mass. Daily creatinine production is fairly constant except when there is massive injury to muscle. The kidneys excrete creatinine very efficiently and blood levels and daily urinary excretion of creatinine fluctuates very little in healthy normal people. Since blood and daily urine excretion of creatinine shows minimal fluctuation, creatinine excretion is useful in determining whether 24-hour urine specimens for other analytes (e.g., protein) have been completely and accurately collected.