Urea Clearance

Urea Clearance

Test Code

7329
84545
7329
84545
Not offered in Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano. Please provide SERVICE AREA INFORMATION to find available tests you can order.
In-home collection is not available in your area through Quest Mobile.

Clinical Significance

Urea Clearance -

This test estimates urea clearance based on the measurements of urea nitrogen levels in a blood specimen and a 24-hour urine specimen [1]. Urea clearance may be helpful in screening for chronic kidney disease and predicting glomerular filtration rate (GFR) in patients with advanced kidney dysfunction [1].

Urea is the main nitrogen-containing product of protein breakdown, and approximately 90% of the urea excretion is through the kidneys. In individuals with normal kidney function, urea clearance is roughly half of creatinine clearance owing to tubular back-diffusion of urea to blood and ...

Test Resources

Test Guide

Laboratory Testing for Chronic Kidney Disease Diagnosis and Management

Test Details

Includes

  • Urea Nitrogen (BUN)
  • Urea Nitrogen, 24 Hour Urine
  • Urea Clearance (calculation)
  •  
  • CPT code 81050 may be added at an additional charge for volume measurement

Methodology

Spectrophotometry (SP)

Reference Range(s)

Urea Nitrogen (BUN)

  Male
(mg/dL)		 Female
(mg/dL)
<1 Month 4-12 3-17
1-11 Months 2-13 4-14
1-3 Years 3-12 3-14
4-19 Years 7-20 7-20
≥20 Years 7-25 7-25

Urea Nitrogen, 24 Hour Urine 6-17 g/24 h
Urea Nitrogen Clearance 41-68 mL/min

LOINC® Codes, Performing Laboratory

Service Area must be determined
Urea Nitrogen (BUN)
Urea Nitrogen, 24 Hour Urine
Urea Clearance (calculation)

CPT code 81050 may be added at an additional charge for volume measurement

Methodology

Spectrophotometry (SP)

Reference Range(s)

Urea Nitrogen (BUN)
  Male
(mg/dL)		 Female
(mg/dL)
<1 Month 4-12 3-17
1-11 Months 2-13 4-14
1-3 Years 3-12 3-14
4-19 Years 7-20 7-20
≥20 Years 7-25 7-25

Urea Nitrogen, 24 Hour Urine 6-17 g/24 h
Urea Nitrogen Clearance 41-68 mL/min
Service Area must be determined

Preferred Specimen(s)

10 mL urine aliquot from a 24-hour urine collection, collected in a plastic urine container, no preservative and
1 mL serum

Alternative Specimen(s)

Urine: Urine preserved with 6N HCl to maintain a pH of <4. Preserved urine may be shipped at room temperature. Urinalysis transport tube (yellow-top, blue fill line, preservative tube) • Plasma collected in: Sodium heparin (green-top) tube or lithium heparin (green-top) tube

Minimum Volume

2 mL urine • 0.5 mL serum or plasma

Collection Instructions

Aliquot from a well-mixed 24-hour collection. Record total volume on both the transport container and the test requisition.

Transport Container

Urine: Plastic urine container
Serum or plasma: Transport tube

Transport Temperature

Urine: Refrigerated (cold packs)
Serum or plasma: Room temperature

Specimen Stability

  • Urine
    Room temperature: 24 hours
    Refrigerated: 7 days
    Frozen: Indefinitely

    Serum and plasma
    Room temperature: 7 days
    Refrigerated: 5 days
    Frozen: 28 days

Reject Criteria

Anticoagulants other than heparin

Setup Schedule

Service Area must be determined
10 mL urine aliquot from a 24-hour urine collection, collected in a plastic urine container, no preservative and
1 mL serum
Urine: Urine preserved with 6N HCl to maintain a pH of <4. Preserved urine may be shipped at room temperature. Urinalysis transport tube (yellow-top, blue fill line, preservative tube) • Plasma collected in: Sodium heparin (green-top) tube or lithium heparin (green-top) tube
2 mL urine • 0.5 mL serum or plasma

Aliquot from a well-mixed 24-hour collection. Record total volume on both the transport container and the test requisition.

Urine: Plastic urine container
Serum or plasma: Transport tube
Urine: Refrigerated (cold packs)
Serum or plasma: Room temperature
Urine
Room temperature: 24 hours
Refrigerated: 7 days
Frozen: Indefinitely

Serum and plasma
Room temperature: 7 days
Refrigerated: 5 days
Frozen: 28 days
Anticoagulants other than heparin
Service Area must be determined
Not offered in Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano. Please provide SERVICE AREA INFORMATION to find available tests you can order.
In-home collection is not available in your area through Quest Mobile.
Test Details

Clinical Significance

Test Resources

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.

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