Calcium, Urine
Use
Reflects intake, rates of intestinal calcium absorption, bone resorption and renal loss. Those processes relate to parathyroid hormone and vitamin D levels. Evaluation of bone disease, calcium metabolism, renal stones (nephrolithiasis);1 idiopathic hypercalciuria,2 and especially, parathyroid disorders. Follow-up of patients on calcium therapy for osteopenia.
Special Instructions
Patient should provide the date and time collection started and finished on the test request form. The total volume should also be indicated. Additional time for test processing may be required for confirmatory or reflex tests.
Limitations
Urinary calcium levels may be decreased in patients on oral contraceptives. The test lacks specificity for diagnosing hyperparathyroidism when increased. It is also noted that five percent of the population may naturally have hypercalciuria. The test may not consistently distinguish hypercalciuria caused by different conditions.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 6874-2
- 18488-7
- 6874-2
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
25 mL aliquot
Minimum Volume
1 mL
Container
Plastic urine container with at least 10 mL 6N HCl (hydrochloric acid)
Collection Instructions
Instruct the patient to void at 8 AM and discard the specimen. Collect all urine including the final specimen voided at the end of the 24-hour collection period (8 AM the next morning). Secure the lid. Transport to the lab with full labeling on the container including patient's name, room number, date and time collection started and finished. pH must be <2.
Patient Preparation
The patient should be on a low calcium, neutral ash diet for three days prior to urine collection. Withdraw drugs affecting mineral metabolism, such as antacids, phosphates, diuretics, glucocorticoids, carbonic anhydrase inhibitors, and anticonvulsants, two to four weeks prior to and during collection if possible.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Improper labeling
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |