Calcium:Creatinine Ratio
Use
A random urine calcium:creatinine ratio is used to screen for hypercalciuria, as it is found to have a good correlation with 24-hour urine calcium excretion.1 Increased urinary excretion of calcium accompanies hyperparathyroidism, vitamin D intoxication, diseases that destroy bone (such as multiple myeloma), metastasis from prostatic cancer, and following calcium supplementation. Urine calcium is increased with immobilization, with steroid therapy, with Paget disease, and in primary (idiopathic) hypercalciuria.
Special Instructions
Final pH of the sample must be adjusted to 1.5−2.0 with 6N HCl before refrigeration. Use random urine transport tube or urine Monovette® with pH stabilizer (Labcorp N° 56015). Monovette® instructions accompany units.
Limitations
The test may have variability based on the collection method and the physiological state of the patient. Factors such as recent dietary calcium intake, hydration status, and timing of collection relative to food intake can affect results. Stability of the sample is maintained for 7 days at room temperature, 14 days refrigerated, and 7 days frozen.
Methodology
Other
Biomarkers
LOINC Codes
- 9321-1
- 18488-7
- 2161-8
- 9321-1
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
Not provided
Minimum Volume
Not provided
Container
random urine transport tube or urine Monovette® with pH stabilizer (Labcorp N° 56015)
Collection Instructions
Collect urine and transfer to a random urine transport tube or urine Monovette® with pH stabilizer (LabCorp N° 56015). Final pH must be <2.
Storage Instructions
After collection, pH is adjusted to 1.5−2.0 with 6N HCl. Refrigerate.
Causes for Rejection
Improperly labeled specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 7 days |