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HelpTest Code LAB1765 Creatinine Clearance, Urine 24 Hour
Additional Codes
CPT Code: 82575
Methodology
Includes blood and urine creatinine and glomerular filtration rate (eGFR).
Performing Laboratory
TidalHealth Peninsula Regional - Core Laboratory: Chemistry
Specimen Requirements
Plasma or serum and urine are required. Plasma or serum SHOULD be drawn during urine collection. However, blood drawn 12 hours BEFORE or AFTER the urine collection is acceptable.
Urine
Submit an entire timed urine collection (2-, 12-, or 24-hour) in a plain jug. Refrigerate specimen during collection, and send specimen refrigerated. Forward promptly to laboratory.
Note: 1. Patient’s height (in cm) and weight (in kg) are required.
2. 50% Acetic acid, boric acid, or 6N HCl are acceptable preservatives.
3. Follow instructions in Urine Collection in Special Instructions.
4. Indicate 2-, 12-, or 24-hour collection on request form.
5. Label specimen appropriately (2-, 12-, or 24-hour collection and as urine).
Submit only 1 of the following specimens:
Plasma
Draw blood in a green-top (lithium heparin) tube. (Hemolyzed specimen is not acceptable.) Spin down and send 2 mL of lithium heparin plasma.
Note: 1. Patient’s height (in cm) and weight (in kg) are required.
2. Indicate plasma.
3. Label specimen appropriately (plasma).
Serum
Draw blood in a gold-top serum gel tube. (Hemolyzed specimen is not acceptable.) Spin down and send 2 mL of serum.
Note: 1. Patient’s height (in cm) and weight (in kg) are required.
2. Indicate serum.
3. Label specimen appropriately (serum).
Reference Values
CREATININE, BLOOD
Males
0-11 months: 0.30-1.00 mg/dL
12 months-11 years: 0.30-0.70 mg/dL
12-17 years: 0.50-1.00 mg/dL
≥18 years: 0.64 - 1.27 mg/dL
Females
0-11 months: 0.30-1.00 mg/dL
12 months-11 years: 0.30-0.70 mg/dL
12-17 years: 0.50-1.00 mg/dL
≥18 years: 0.44-1.03 mg/dL
Note: Serum acetoacetate will lower creatinine results. Acetone and α-ketobutyric acid will elevate results.
CREATININE, URINE
Males: 0.8-2.0 g/24 hours
Females: 0.6-1.50 g/24 hours
CREATININE CLEARANCE
Pediatric normal ranges are available.
Call Chemistry at 410-543-7386 ext. 4219 for ranges if <20 years.
Males
20-29 years: 88-146 mL/min
30-39 years: 82-140 mL/min
40-49 years: 75-133 mL/min
50-59 years: 68-126 mL/min
60-69 years: 61-120 mL/min
70-79 years: 55-113 mL/min
Females
20-29 years: 81-134 mL/min
30-39 years: 75-128 mL/min
40-49 years: 69-122 mL/min
50-59 years: 64-116 mL/min
60-69 years: 58-110 mL/min
70-79 years: 52-105 mL/min
For each decade over 20 years, the normal range decreases by approximately 6.5 mL/min.
Estimated Glomerular Filtration Rate (eGFR) by CKD-EPI Equation
eGFR Reference Range: ≥60 mL/min/1.73 m2
When calculating eGFR, the equation takes into account the patient’s serum creatinine, age, sex, and race. African-American and non-African American eGFR values will be reported from the eGFR calculation.
eGFR will not be reported for patients <18 years of age. eGFR by this equation has been shown to be valid for diabetic patients but not for pregnant patients. It is not recommended using this for drug dosing - for drug dosing use the CG equation.
According to the Kidney Disease: Improving Global Outcomes (KDIGO) CKD work group, chronic kidney disease (CKD) is defined as the abnormalities of kidney structure or function, present for more than 3 months, with implications for health. CKD should be classified by cause, GFR category, and albuminuria category.
KDIGO guidelines provide the following GFR categories:
|
Stage |
Terms |
GFR mL/min/1.73 m |
|
G1* |
Normal or high |
90 |
|
G2* |
Mildly decreased |
60 to 89 |
|
G3a |
Mildly to moderately decreased |
45 to 59 |
|
G3b |
Moderately to severely decreased |
30-44 |
|
G4 |
Severely decreased |
15-29 |
|
G5 |
Kidney failure |
<15 |
*In the absence of evidence of kidney damage, neither G1 nor G2 fulfill criteria for CKD.
Clinical Reference
Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int Suppl 2013;3:1-150
KDOQI US Commentary on the 2012 KDIGO Clinical Practice Guideline for the Evaluation and Management of CKD. Am J Kidney Dis 2014;63:713-735
Additional Information
Do not order as “nurse to collect” since blood draw is required during urine collection.
For inpatients, check to ensure patient’s height (in cm) and weight (in kg) have been entered prior to ordering.