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22939 Urea Clearance

Urea Clearance
Test Code: URCLHW
Synonyms/Keywords
Urea Clear (Corr with Ht/Wt)​
Test Components
Blood Urea, Urine Urea and Creatinine​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​
Urine
AND
Plasma​/Serum
Urine Container
 
Lithium-heparin Plasma Separator (PST)​, Serum Separator Tube (SST)
 Lithium or Sodium-heparin Green Top (GTT)​, Red Top Tube (RTT)
10 mL Urine
AND
1 mL Plasma/Serum
​
1 mL Urine
 AND
0.3 mL Plasma/Serum
​		 ​
Collection Processing Instructions
Aliquot from timed urine (24 hour or 48 hour collection interval is preferred) collected without a preservative. The total volume collected must be measured, recorded, and included with the test request.
 
 
The blood specimen ideally should be drawn during the urine collection time interval, however blood specimens drawn no longer than 24 hours prior to the start of the collection or within 24 hours after the collection ends are usually acceptable.
Patient's height (within 1 inch) and weight (within 10 lbs) should be submitted with the request to allow for result correction to standardized 1.73 sq. meter body surface area.
Clearance is calculated using the usual method (U/P x V) and makes no correction for tubular reabsorption at slower urine flow rates, i.e. the "maximum urea clearance" is assumed.
The blood specimen must be ordered separately as either a BUN or as part of a Basic Metabolic Profile. ​
Specimen Stability Information
Specimen Type Temperature Time
Urine​ - No Preservative ​ Ambient 2 hours
​Refrigerate ​4 days
​Urine - With Preservative ​Refrigerate ​7 days
Plasma​/Serum ​ ​ Ambient 5 days
​Refrigerate​ ​7 days​
Frozen​ 3 months​
Rejection Criteria
​Plasma or serum specimens collected in ammonium heparinate or oxalate
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Lakeview Medical Center​ ​Monday through Sunday​ ​Less than 2 hours ​Biochromatic Rate Technique/Siemens Dimension
Marshfield​ Monday through Sunday​ 6-8 hours​ Urease GLDH & Modified Jaffe/Beckman AU​
Reference Range Information
Performing Location Reference Range
All Performing Sites 64-99 mL/min​
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84545 ​ ​ ​ ​ ​
Synonyms/Keywords
Urea Clear (Corr with Ht/Wt)​
Test Components
Blood Urea, Urine Urea and Creatinine​
Ordering Applications
Ordering Application Description
​Centricity ​Urea Clear 24-48 Hr
​Cerner ​Urea Clear (Corr with Ht/Wt)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​
Urine
AND
Plasma​/Serum
Urine Container
 
Lithium-heparin Plasma Separator (PST)​, Serum Separator Tube (SST)
 Lithium or Sodium-heparin Green Top (GTT)​, Red Top Tube (RTT)
10 mL Urine
AND
1 mL Plasma/Serum
​
1 mL Urine
 AND
0.3 mL Plasma/Serum
​		 ​
Collection Processing
Aliquot from timed urine (24 hour or 48 hour collection interval is preferred) collected without a preservative. The total volume collected must be measured, recorded, and included with the test request.
 
 
The blood specimen ideally should be drawn during the urine collection time interval, however blood specimens drawn no longer than 24 hours prior to the start of the collection or within 24 hours after the collection ends are usually acceptable.
Patient's height (within 1 inch) and weight (within 10 lbs) should be submitted with the request to allow for result correction to standardized 1.73 sq. meter body surface area.
Clearance is calculated using the usual method (U/P x V) and makes no correction for tubular reabsorption at slower urine flow rates, i.e. the "maximum urea clearance" is assumed.
The blood specimen must be ordered separately as either a BUN or as part of a Basic Metabolic Profile. ​
Specimen Stability Information
Specimen Type Temperature Time
Urine​ - No Preservative ​ Ambient 2 hours
​Refrigerate ​4 days
​Urine - With Preservative ​Refrigerate ​7 days
Plasma​/Serum ​ ​ Ambient 5 days
​Refrigerate​ ​7 days​
Frozen​ 3 months​
Rejection Criteria
​Plasma or serum specimens collected in ammonium heparinate or oxalate
Test Components
Blood Urea, Urine Urea and Creatinine​
Reference Range Information
Performing Location Reference Range
All Performing Sites 64-99 mL/min​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Lakeview Medical Center​ ​Monday through Sunday​ ​Less than 2 hours ​Biochromatic Rate Technique/Siemens Dimension
Marshfield​ Monday through Sunday​ 6-8 hours​ Urease GLDH & Modified Jaffe/Beckman AU​
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84545 ​ ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.