Creatinine, Urine

Diagnostic Use

Creatinine is a waste product produced by skeletal muscle tissue. Creatinine is usually measured in the plasma as a biomarker of renal function.

Because creatinine is produced and excreted at a constant rate, urine creatinine concentration can be measured to assess the concentration of a urine specimen. This is particularly relevant when measuring the concentration of another analyte in urine, which can be corrected for urine concentration by expressing that analyte as a ratio to creatinine concentration (e.g. albumin/creatinine ratio).

Whilst plasma creatinine is normally measured to assess renal function, urine creatinine is measured when calculating creatinine clearance, a largely outdated method of assessing glomerular filtration.

Department

Core Biochemistry

Delphic Registration Code

UCRN

Synonyms

UCRN

Turnaround Time

3 hours

Test Code

3544

Specimen Type

• Urine

Specimen Requirements

Tube/Container Type:

Preferred

• 24hr Urine Container

Acceptable

• Pottle

Aliquot Instructions

Sample Type

• Urine

Minimum Volume (ml)

0.1

Interpretation

A low urine creatinine may indicate an incomplete collection of a 24 hour urine sample, whereas an elevated urine creatinine may indicate an over-collection.

Creatinine concentration is related to muscle mass, therefore lower-than-expected results may be seen in those with low muscle bulk, and results above the reference interval may be seen in those with large muscle mass.  Consumption of creatine supplements will also increase the urine creatinine concentration, as the assay is unable to differentiate between creatine and creatinine.

Reference Intervals

The reference intervals below relate to a 24 hour timed urine collection

Test Method

Enzymatic spectrophotometry on a Beckman Coulter AU5822 analyser using Beckman Coulter reagents.

Non-Funded Test Cost

$4.38 (Exclusive of GST)

Billing Code

3544

Contact Information

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