Lab Test

Creatinine, Urine

Urine Creatinine

Test Codes

24 Hour Urine: EPIC: LAB5444, CRU24, Random Urine: EPIC: LAB5035, CREAU

Instructions

Note: 24 hour and random urine specimens MUST be collected separately. See below for collection criteria.

Specimen Collection Criteria

Collect: 24 hour urine or timed urine specimen with a 24 hour urine container with no preservatives.
Also acceptable: Random urine specimen in a screw-capped container (preferred) or another sterile collection cup. Preservatives are not acceptable for random urine specimens. (Minimum: 20 mL)

  • Refer to the table of Urine Preservative Options when multiple tests are requested.
  • Keep 24 hour urine specimen iced or refrigerated during collection.
  • Include start and end dates and times for the collection period on the specimen container.
Urine Preservative Options
No Preservative
6N Hydrochloric Acid
Boric Acid (10g)
Sodium Carbonate
50% Acetic Acid
PREFERRED
Acceptable
Acceptable
Acceptable
Acceptable

Physician Office/Draw Specimen Preparation

Maintain specimens refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Entire 24 hour urine collection, timed urine, or the random urine, refrigerated (2-8°C or 36-46°F).

Rejection Criteria

Specimens not collected and processed as indicated.

In-Lab Processing

Measure total volume of 24 hour or timed urine specimen. Record total volume and collection start and end dates and times in the LIS system. Aliquot a minimum of 10 mL from the well-mixed 24 hour or timed urine collection.

Storage

Specimen Stability for Testing:

Room temperature (20-26°C or 68-78.8°F): 4 hours
Refrigerated (2-8°C or 36-46°F): 4 days
Frozen (-20°C/-4°F or below): For longer storage.

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days (Royal Oak and Troy store an aliquot for 30 days.)

Laboratory

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory
Wayne Chemistry Laboratory

Performed

Sunday – Saturday.
Routine results available within 24 hours. 

Reference Range

Urine Creatinine: 800 - 2,500 mg/24 hours.
Normal ranges for random urines or for collections other than 24 hours have not been established.

Test Methodology

Spectrophotometry.

Interpretation

  • Urine creatinine may be increased due to exercise, infections, meat meals, diabetes mellitus, hypothyroidism, and acromegaly.
  • It may be decreased in advanced renal disease, diseases with decreased muscle mass, muscular dystrophy, inflammatory or metabolic diseases of muscle, hyperthyroidism, anemia, leukemia, and vegetarian diets. This test is NOT useful in evaluating renal function except as part of a Creatinine Clearance test.

Clinical Utility

This assay aids in the diagnosis and management of renal diseases (when done as part of a Creatinine Clearance test), in monitoring renal dialysis, and as a calculation basis for measuring other urine analytes.

CPT Codes

82570
LOINC: 2161-8, 20624-3, 14683-7, 24-Hour 2162-6, Random 20624-3, 2161-8, Urine 2161-8

Contacts

Last Updated

7/20/2021

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