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22401 Calcium/Creatinine Clearance Ratio, 24 Hr Urine

Calcium/Creatinine Clearance Ratio, 24 Hr Urine
Test Code: 24 CA-CL
Synonyms/Keywords
Fractional Excretion of Calcium​
Test Components
Urine and Blood Creatinine, Urine and Blood Calcium
Useful For
Measurement of the ratio of calcium clearance to creatinine clearance (fractional excretion of calcium) has been used primarily for distinguishing familial benign hypercalcemia from other causes of increased serum calcium in adult patients. Generally, benign hypercalcemia is characterized by a decreased urine calcium excretion, resulting in a decreased clearance ratio. 
Specimen Requirements
 ​


Fasting RequiredSpecimen TypePreferred Container/TubeAcceptable Container/TubeSpecimen VolumeSpecimen Minimum Volume
(allows for 1 repeat)
No​ ​
24 Hour Urine

24 Hour Urine jug with 7g sulfamic acid as a preservative

24 Hour Urine jug with 20 mL 6N HCL or 25 mL 33% acetic acid​

10.0​ mL​2.0 mL​

*Plasma/Serum (*See Collection Instructions)

Lithium-heparin Plasma Separator Tube (PST)

 Serum Separator Tube (SST), Lithium or Sodium-Heparinized Green Top Tube (GTT) or Red Top Tube (RTT)

1.0 mL​0.3 mL​
Collection Processing Instructions
*If there is no other blood calcium or creatinine order on the same encounter within 24 hours of urine collection a blood order of CABLD (Ca and Creat for Ca/Cr Ratio) will be reflexed when the urine order is completely activated and should be drawn when the patient returns the timed urine collection.

Note: Blood specimens are acceptable no earlier than 24 hours prior to the start of the urine collection or no later than 24 hours after the collection ends.

Urine
Specimen Stability Information
Specimen Type Temperature Time
Urine​ - W/Preservative
 Refrigerate​ 7 days
Plasma/Serum
​​
 Refrigerate​ 7 days
​Ambient
​5 days
Rejection Criteria

​If either the blood or urine specimen is not available, the test cannot be performed. ​

Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Sunday​ Less than 2 hours Arsenazo III Endpoint Assay/Beckman AU​
Modified Jaffe Kinetic Fixed Assay/Beckman Coulter AU
Reference Range Information
Performing Location Reference Range
Marshfield​

Benign hypercalcemia: <0.010

Indeterminate: 0.010-0.020

Possible hyper-PTH: >0.020​

Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82340​ ​ ​ Calcium, Urine​ ​
82310​ ​ ​ Calcium, Serum​ If needed
82570​
​
​
​Creatinine, other source
​
​82565
​​
​
​Creatinine, blood
​If needed
Synonyms/Keywords
Fractional Excretion of Calcium​
Test Components
Urine and Blood Creatinine, Urine and Blood Calcium
Ordering Applications
Ordering Application Description
4medica
 ​Calcium/Creatinine Clearance Ratio, 24 Hr Urine
​Cerner ​Calcium/Creatinine Clearance Ratio, 24 Hr Urine
CA-CL
24 CA-CL
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
 ​


Fasting RequiredSpecimen TypePreferred Container/TubeAcceptable Container/TubeSpecimen VolumeSpecimen Minimum Volume
(allows for 1 repeat)
No​ ​
24 Hour Urine

24 Hour Urine jug with 7g sulfamic acid as a preservative

24 Hour Urine jug with 20 mL 6N HCL or 25 mL 33% acetic acid​

10.0​ mL​2.0 mL​

*Plasma/Serum (*See Collection Instructions)

Lithium-heparin Plasma Separator Tube (PST)

 Serum Separator Tube (SST), Lithium or Sodium-Heparinized Green Top Tube (GTT) or Red Top Tube (RTT)

1.0 mL​0.3 mL​
Collection Processing
*If there is no other blood calcium or creatinine order on the same encounter within 24 hours of urine collection a blood order of CABLD (Ca and Creat for Ca/Cr Ratio) will be reflexed when the urine order is completely activated and should be drawn when the patient returns the timed urine collection.

Note: Blood specimens are acceptable no earlier than 24 hours prior to the start of the urine collection or no later than 24 hours after the collection ends.

Urine
Specimen Stability Information
Specimen Type Temperature Time
Urine​ - W/Preservative
 Refrigerate​ 7 days
Plasma/Serum
​​
 Refrigerate​ 7 days
​Ambient
​5 days
Rejection Criteria

​If either the blood or urine specimen is not available, the test cannot be performed. ​

Useful For
Measurement of the ratio of calcium clearance to creatinine clearance (fractional excretion of calcium) has been used primarily for distinguishing familial benign hypercalcemia from other causes of increased serum calcium in adult patients. Generally, benign hypercalcemia is characterized by a decreased urine calcium excretion, resulting in a decreased clearance ratio. 
Test Components
Urine and Blood Creatinine, Urine and Blood Calcium
Reference Range Information
Performing Location Reference Range
Marshfield​

Benign hypercalcemia: <0.010

Indeterminate: 0.010-0.020

Possible hyper-PTH: >0.020​

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Sunday​ Less than 2 hours Arsenazo III Endpoint Assay/Beckman AU​
Modified Jaffe Kinetic Fixed Assay/Beckman Coulter AU
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82340​ ​ ​ Calcium, Urine​ ​
82310​ ​ ​ Calcium, Serum​ If needed
82570​
​
​
​Creatinine, other source
​
​82565
​​
​
​Creatinine, blood
​If needed
For most current information refer to the Marshfield Laboratory online reference manual.