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22401 Calcium/Creatinine Clearance Ratio (Adult)

Calcium/Creatinine Clearance Ratio (Adult)
Test Code: CA-CL
Synonyms/Keywords
Fractional Excretion of Calcium​
Test Components
Urine and Serum Calcium, Urine and Serum Creatinine​
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)
Pediatric Minimum Volume
(no repeat)
No​ ​
24 hr
urine
24 hour urine jug with 7 g sulfamic acid as a preservative​

24 hr urine jug with 20 mL 6N HCL

or 25 mL  33% acetic acid ​

10 mL​2 mL​N/A​

And Plasma/Serum​

Lithium-heparin Plasma Separator Tube (PST)

 

Lithium or Sodium - Heparinized Green Top Tube (GTT)
Gold Top Tube (GDTT)

or

Red Top Tube (RTT)

1.0 mL​0.3 mL​0.3 mL of whole blood​
Collection Processing Instructions
10 mL from a well-mixed 24 hour urine collected with 7 g. sulfamic acid AND 2 mL heparinized plasma or serum (10 mL PST, 7 mL green, or 10 mL red) for blood calcium and creatinine analyses.
Indicate the collection time.
The total volume collected must be measured, recorded, and included with the test request.
NOTE: This test code (CA-CL) does not order the blood tests necessary to calculate this test ratio, therefore the phlebotomist must also order the test code CACLBD when the patient brings in the timed urine collection. Collect blood specimen within 24 hours of the urine collection. 
If uric acid is also ordered, See "Aliquotting of 24-Hour Urines for Multiple Tests".
Specimen Stability Information
Specimen Type Temperature Time
Urine​ Refrigerate​ 2 weeks​
Serum/Plasma​ Refrigerate​ 1 week​
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​
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​
Synonyms/Keywords
Fractional Excretion of Calcium​
Test Components
Urine and Serum Calcium, Urine and Serum Creatinine​
Ordering Applications
Ordering Application Description
​Centricity ​Ca/Creat Clear Ratio
​Cerner ​Calcium/Creatinine Clearance Ratio, 24 Hr Urine
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)
Pediatric Minimum Volume
(no repeat)
No​ ​
24 hr
urine
24 hour urine jug with 7 g sulfamic acid as a preservative​

24 hr urine jug with 20 mL 6N HCL

or 25 mL  33% acetic acid ​

10 mL​2 mL​N/A​

And Plasma/Serum​

Lithium-heparin Plasma Separator Tube (PST)

 

Lithium or Sodium - Heparinized Green Top Tube (GTT)
Gold Top Tube (GDTT)

or

Red Top Tube (RTT)

1.0 mL​0.3 mL​0.3 mL of whole blood​
Collection Processing
10 mL from a well-mixed 24 hour urine collected with 7 g. sulfamic acid AND 2 mL heparinized plasma or serum (10 mL PST, 7 mL green, or 10 mL red) for blood calcium and creatinine analyses.
Indicate the collection time.
The total volume collected must be measured, recorded, and included with the test request.
NOTE: This test code (CA-CL) does not order the blood tests necessary to calculate this test ratio, therefore the phlebotomist must also order the test code CACLBD when the patient brings in the timed urine collection. Collect blood specimen within 24 hours of the urine collection. 
If uric acid is also ordered, See "Aliquotting of 24-Hour Urines for Multiple Tests".
Specimen Stability Information
Specimen Type Temperature Time
Urine​ Refrigerate​ 2 weeks​
Serum/Plasma​ Refrigerate​ 1 week​
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 Serum Calcium, Urine and Serum Creatinine​
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​
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
82340​ Calcium, Urine​
82310​ Calcium, Serum​
For most current information refer to the Marshfield Laboratory online reference manual.