Calcium is an essential mineral involved in bone health, muscle contraction, and nerve function.

Normally, the kidneys regulate calcium excretion to maintain balance.

Measuring calcium in a spot urine sample provides a quick assessment of urinary calcium excretion.

Clinical uses include:

Screening for hypercalciuria (excess calcium in urine).

Evaluating patients with kidney stones (nephrolithiasis).

Assessing parathyroid disorders (hyperparathyroidism, hypoparathyroidism).

Monitoring calcium metabolism in metabolic bone disease.

Often performed alongside serum calcium, phosphorus, PTH, and vitamin D tests.

Analyte: Calcium in urine (mg/dL or mmol/L).

Normal Range (varies by lab): Typically < 200 mg/day in adults (spot values interpreted relative to creatinine).

Abnormal Findings:

High urine calcium (hypercalciuria): Kidney stones, hyperparathyroidism, vitamin D excess, renal tubular disorders.

Low urine calcium (hypocalciuria): Hypoparathyroidism, vitamin D deficiency, malabsorption, chronic kidney disease.

Clinical Use:

Provides a marker of calcium excretion and metabolic balance.

Helps guide diagnosis and management of kidney stones and parathyroid disorders.

Supports nephrology and endocrinology evaluations.