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Test Code CREAU24H Creatinine Urine 24 Hour

Additional Codes

Cerner

NextGen

Creatinine Urine 24 Hr

Creatinine Urine 24 Hr

Useful For

Serum creatinine and urinary creatinine excretion is a function of lean body mass in normal persons and shows little or no response to dietary changes. The serum creatinine concentration is higher in men than in women. Since urinary creatinine is excreted mainly by glomerular filtration, with only small amounts due to tubular secretion, serum creatinine and a 24-hour urine creatinine excretion can be used to estimate the glomerular filtration rate.

Serum creatinine is increased in acute or chronic renal failure, urinary tract obstruction, reduced renal blood flow, shock, dehydration, and rhabdomyolysis. Causes of low serum creatinine concentration include debilitation and decreased muscle mass. Exercise may cause an increased creatinine clearance. The creatinine clearance rate is unreliable if the urine flow is low.

Methodology

Enzymatic, Two-point rate

Patient Preparation

None

Collection Instructions

Catheterized specimens collected according to clinical policies and procedures

24 Hour Urine Collection Instructions

Specimen Requirements

Container

Stability

Storage

Temperature

Stability

Room Temperature

18-28°C

≤ 3 day

Refrigerated

 2-8°C

≤ 5 day

Frozen

≤-18 °C

Indefinite

Rejection Criteria

Not Defined

Result Reporting and Reference Values

Reported in g/24 hr

AGE

Gender

Low

High

Critical Low

Critical High

<18 years

Both

Reference ranges not established

N/A

N/A

18- 150 years

Male

1.0

2.0

N/A

N/A

18-150 years

Female

0.8

1.8

N/A

N/A

Reflex Testing

None

Limitations

  • Ortho reports the following additional biases:
    • Dipyrone (Metamizol) at 18.0 mg/dL shows a negative bias, consult IFU
    • Tolazamide at 4.5 mg/dL shows a negative bias, consult IFU
    • Proline- Patient receiving hyperalimentation fluids contain proline may show a positive bias
    • Lidocaine- patients on long term lidocaine therapy may show a positive bias, consult IFU.
  • Ortho reports no significant effect with the following: 
    • Bilirubin up to 20 mg/dl
    • Hemoglobin up to 900 mg/dl
    • Lipemia up to 800 mg/dL
  • The following interpretive data is visible to the practitioner:
    • Patient receiving hyperalimentation fluids containing Proline may have a positive bias. Specimens contaminated with Dobutamine from IV fluids show a significant negative bias. Patients on long term Lidocaine therapy show a significant positive bias. Dipyrone and N-acetylcysteine show significant negative bias.