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HelpTest Code 24 CA-CL Calcium/Creatinine Clearance Ratio, 24 Hr Urine
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.
Synonyms/Keywords
Fractional Excretion of Calcium
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen 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 CACLBD (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. OUTREACH clients should manually order CACLBD and send blood sample with urine sample.
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
- Indicate the collection time.
- The total volume collected must be measured, recorded, and included with the test request.
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.
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 |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing 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 |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82340 | Calcium, Urine | |||
| 82310 | Calcium, Serum | If needed | ||
| 82570 | Creatinine, other source | |||
| 82565 | Creatinine, blood | If needed |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82340 | Calcium, Urine | |||
| 82310 | Calcium, Serum | If needed | ||
| 82570 | Creatinine, other source | |||
| 82565 | Creatinine, blood | If needed |
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 |