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Calcium, Random Urine with Creatinine : 1633
Test CodeURCAES or 1633
CPT Codes
82310, 82570
Preferred Specimen
10 mL random Urine
Minimum Volume
2 mL
Other Acceptable Specimens
Unpreserved urine collected in urinalysis transport tube (yellow-top, blue fill line, preservative tube) • Preserved urine with 6N HCl acid submitted in a plastic, urine container
Instructions
Collect 10 mL random urine in a plastic, screw-cap container and adjust pH to <2 with 6N HCl. Aliquot urine specimens and send at room temperature to the laboratory
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It is acceptable to add preservative after collection if urine is refrigerated during collection. Record total volume and collection time on specimen container and requisition.
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It is acceptable to add preservative after collection if urine is refrigerated during collection. Record total volume and collection time on specimen container and requisition.
Transport Container
Plastic urine container
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 5 days
Refrigerated: 35 days
Frozen: 6 months
Refrigerated: 35 days
Frozen: 6 months
Methodology
Spectrophotometry
Setup Schedule
Sunday - Saturday
Report Available
1 day
Reference Range
See Laboratory Report
Clinical Significance
This quantitative test, performed with a random urine specimen, may help screen for hypercalciuria, one of the established risk factors for kidney stone formation [1-3]. This test may also help assess metabolic disorders of calcium metabolism, such as hyperparathyroidism, bone disease, and idiopathic hypercalciuria. To adjust for the concentration differences in random urine specimens, calcium to creatinine ratio is included in the results. In general, 24-hour urine specimens are preferred to random urine specimens when measuring calcium for diagnostic evaluation of hypercalciuria [1]. Calcium is essential for bone formation and nerve, muscle, and heart functions. Calcium metabolism is jointly regulated by parathyroid hormone and vitamin D metabolites. Urinary calcium excretion is the major route of calcium elimination and reflects kidney tubular filtration and reabsorption of calcium in addition to dietary intake, intestinal absorption, and bone resorption [2].
Urinary calcium levels may be elevated in patients with idiopathic hypercalciuria, chronic kidney disease, hyperparathyroidism, vitamin D intoxication, Paget disease of bone, sarcoidosis, or conditions that infiltrate and destroy bones (eg, multiple myeloma and a variety of metastatic cancers) [2,3]. Urinary calcium levels may be decreased in patients with hypoparathyroidism, vitamin D deficiency rickets, osteomalacia, or familial hypocalciuric hypercalcemia [2,3].
Note that use of calcium supplements and loop diuretics may cause increased urinary calcium levels; thiazide diuretics may cause decreased urinary calcium levels [3]. The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Williams JC Jr, et al. Urolithiasis. 2021;49(1):1-16. 2. Rifai N, et al. eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elservier Inc; 2022 3. MedlinePlus [Internet]. Calcium-urine. Accessed September 1, 2022. https://medlineplus.gov/ency/article/003603.htm
Urinary calcium levels may be elevated in patients with idiopathic hypercalciuria, chronic kidney disease, hyperparathyroidism, vitamin D intoxication, Paget disease of bone, sarcoidosis, or conditions that infiltrate and destroy bones (eg, multiple myeloma and a variety of metastatic cancers) [2,3]. Urinary calcium levels may be decreased in patients with hypoparathyroidism, vitamin D deficiency rickets, osteomalacia, or familial hypocalciuric hypercalcemia [2,3].
Note that use of calcium supplements and loop diuretics may cause increased urinary calcium levels; thiazide diuretics may cause decreased urinary calcium levels [3]. The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Williams JC Jr, et al. Urolithiasis. 2021;49(1):1-16. 2. Rifai N, et al. eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elservier Inc; 2022 3. MedlinePlus [Internet]. Calcium-urine. Accessed September 1, 2022. https://medlineplus.gov/ency/article/003603.htm
Performing Laboratory
med fusion
