Lab Test: Creatinine (Urine) Level
- Measurement of urine creatinine along with serum creatinine to determine glomerular filtration rater (GFR)
- Males (20 to 29 years): 94-140 mL/min/1.73 m2 (0.91-1.35 mL/s/m2)
- Females (20 to 29 years): 72-110 mL/min/1.73 m2 (0.69-1.06 mL/s/m2)
- Males (30 to 39 years): 59-137 mL/min/1.73 m2 (0.57-1.32 mL/s/m2)
- Females (30-39 years): 71-121 mL/min/1.73 m2 (0.68-1.17 mL/s/m2)
- Note: For each decade after the fourth decade in both sexes, values decrease approximately 6.5 mL/min based on 1.73 m2 body surface (0.06 mL/s per m2)
- Infant (0 to 1 year: 72 mL/min/1.73 m2 (0.43 mL/s/m2)
- Infant (1 year): 45 mL/min/1.73 m2 (0.43 mL/s/m2)
- Infant (2 years): 55 mL/min/1.73 m2 (0.53 mL/s/m2)
- Children (3 years): 60 mL/min/1.73 m2 (0.58 mL/s/m2)
- Children (4 years): 71 mL/min/1.73 m2 (0.68 mL/s/m2)
- Children (5 years): 73 mL/min/1.73 m2 (0.70 mL/s/m2)
- Children (6 years): 64 mL/min/1.73 m2 (0.62 mL/s/m2)
- Children (7 years): 67 mL/min/1.73 m2 (0.65 mL/s/m2)
- Children (8 years): 72 mL/min/1.73 m2 (0.69 mL/s/m2)
- Children (9 years): 83 mL/min/1.73 m2 (0.80 mL/s/m2)
- Children (10 years): 89 mL/min/1.73 m2 (0.86 mL/s/m2)
- Children (11 years): 92 mL/min/1.73 m2 (0.89 mL/s/m2)
- Children (12 years): 109 mL/min/1.73 m2 (1.05 mL/s/m2)
- Children (13 to 14 years): 86 mL/min/m2 (0.83 mL/s/m2)
- Suspected gout - increased creatinine clearance may indicate an increased glomerular filtration rate, and may be seen with a high-protein diet and hypercatabolic states
- Suspected impaired renal function - Stages of chronic kidney disease and related GFRs expressed in mL/min/1.73 m2:
- Stage 1: kidney damage evident with abnormal or increased GFR - > 90
- Stage 2: kidney damage with a mild decrease in GFR - 60 to 89
- Stage 3: moderate decrease - GFR 30 to 59
- Stage 4: severe decrease - GFR 15 to 29
- Stage 5: renal failure - GFR < 15 or dialysis
renal impairment is described as a GFR of less than 60 mL/min/1.73 m2.
- A persistently decreased GFR (< 60 mL/min/1.73 m2) along with proteinuria are important criteria used in chronic kidney disease to predict end stage renal disease.
- In the early stages of Type 1 diabetes, the GFR can be increased (greater than 130mL/min/1.73 m2) and is followed by persistent microalbuminuria, which as been associated with a 400% to 500% increase in the risk of progression to overt proteinuria and eventual end stage renal disease.
- Patients with type II DM may present with evidence of a decreased GFR ( less than 60 mL/min/1.73 m2) at the time of diagnosis.
- Diabetic patients (type 1 or 2) that have a normal to moderately decreased GFR (between 30 to 59 mL/min/1.73 m2; stages 1 through 3 of staging system) should be routinely monitored and treated to slow the progression of disease. Renal replacement therapy is likely when the GFR is between 15 to 29 (stage 4). A GFR of less than 15 or requirement for dialysis indicates a need for renal replacement therapy once uremia is present (stage 5).
- A 24-hour urine collection is more physiologically complete than a spot collection because it accounts for the normal variations that can influence renal function. However, studies have compared short- (e.g., 8 hour collections) and longer-duration urine creatinine clearance tests, and found similar results.
- Results decreased in:
- Advanced age (i.e. greater than 80 years) - GFR can decrease at a rate of 13 mL/decade aft4er ages 45 to 50 years, acute and chronic renal failure, inadequate urine flow rate (i.e., due to dehydration or incomplete voiding), exercise, muscle wasting.
- Results increased in:
- Creatinine clearance can overestimate GFR by 10% to 20% at all levels of renal function, pregnancy (rises rapidly in early pregnancy and remains elevated until term; returns to normal quickly following delivery)
- Gender (males have higher GFR, as compared to females), diet can influence renal function, and diurnal variation (i.e., GFR typically lower at night and highest in late morning).
- Collect urine for 24 hours
- Record patient's height and weight with urine sample
- Collect serum/plasma at midpoint of urine collection period
- Store sample on ice or refrigerate during collection period
- Refrigerate sample until laboratory analysis
Indications & Uses
Storage and Handling
MESH Terms & Keywords