Calcium, 24‑Hour Urine (w/ Creatinine)
Use
This quantitative test, performed with a 24‑hour urine specimen, may help screen for hypercalciuria, one of the established risk factors for kidney stone formation. It also helps assess metabolic disorders of calcium metabolism such as hyperparathyroidism, bone disease, and idiopathic hypercalciuria. In general, 24‑hour urine specimens are preferred to random urine specimens when measuring calcium for diagnostic evaluation of hypercalciuria. Calcium is essential for bone formation and nerve, muscle, and heart functions. Calcium metabolism is regulated by parathyroid hormone and vitamin D metabolites. Urinary calcium excretion reflects kidney tubular filtration and reabsorption as well as dietary intake, intestinal absorption, and bone resorption. Creatinine excretion is useful in determining whether the 24‑hour urine specimen has been fully and accurately collected, as daily urinary creatinine excretion shows minimal fluctuation.
Special Instructions
Not provided.
Limitations
Oral contraceptive use may depress results. Use of calcium supplements and loop diuretics may increase urinary calcium; thiazide diuretics may decrease it. Results should be interpreted in the context of clinical and family history and physical exam.
Methodology
Other
Biomarkers
Calcium, 24‑Hour Urine
AnalyteCreatinine, 24‑Hour Urine
Analyte
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
10 mL
Minimum Volume
2 mL
Container
24‑hour urine in urinalysis transport tube (yellow‑top, blue fill line, preservative)
Collection Instructions
Collect all voidings over 24 hours in preservative tube; refrigerate during and after collection; do not include first morning specimen; last collection is next day’s first morning void
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 5 days |
| Refrigerated | 35 days |
| Frozen | 6 months |
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