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Urinary Calcium

Urine Analysis Biomarker

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Collection Type: Urine

Body System

Related System: Urine Analysis

Overview

Urinary calcium measures the amount of calcium excreted in urine (commonly collected over 24 hours or estimated by a spot urine calcium/creatinine ratio). It reflects intestinal absorption, bone turnover and renal handling of calcium. The test is used when kidney stones, unexplained high serum calcium, osteoporosis or recurrent fractures are suspected; symptoms prompting testing include flank pain, hematuria, bone pain, muscle weakness or polyuria. Results vary with age (children normally excrete relatively more), pregnancy (increased excretion), menopausal status, dietary calcium and sodium intake, and medications (e.g., diuretics). Renal function and ethnic/genetic factors (e.g., familial hypocalciuric hypercalcemia) also influence values.

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Test Preparation

Collect a Random/Spot urine sample in a sealed and sterile screw-capped container provided by our sample collection professional
Women are advised not to give the sample during the menstrual period unless prescribed
Blood contaminated and highly turbid samples are not acceptable

Why Do I Need This Test

Profile: included in Urine Analysis (often as a focused metabolic stone or calcium metabolism evaluation).
Symptoms: recurrent kidney stones, unexplained hypercalcemia, bone loss/fractures, muscle weakness.
Diagnoses/monitoring: hypercalciuria, nephrolithiasis risk assessment, primary hyperparathyroidism, vitamin D excess, monitoring treatment (e.g., thiazides).
Reasons for abnormal levels: altered diet, diuretics, parathyroid disease, malignancy, immobilization, renal disease.
Biological meaning & lifestyle causes: high urine calcium means increased bone resorption or absorption/renal leak; low urine calcium may indicate low intake, thiazide therapy or familial hypocalciuric hypercalcemia.
Family history of kidney stones or hypercalcemia warrants testing.

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Understanding Test Results

Values >300 mg/24 hr (>7.5 mmol/24 hr) constitute hypercalciuria and raise risk for calcium kidney stones and bone loss.
Mild hypercalciuria (300–400 mg/day) often reflects dietary/salt excess, high vitamin D or idiopathic hypercalciuria; values persistently >400–500 mg/day suggest primary hyperparathyroidism, malignancy-driven bone resorption, or vitamin D intoxication and merit prompt endocrine/oncologic workup.
Values <100 mg/24 hr suggest hypocalciuria, which can reflect low dietary calcium, thiazide use, reduced intestinal absorption, or familial hypocalciuric hypercalcemia (notable when serum calcium is high but urine calcium low).
Borderline or unexpected results should be confirmed with repeat 24‑hour collections, spot Ca/creatinine ratio, and correlated with serum calcium, PTH, vitamin D and creatinine to determine cause.

Normal Range

100-300 mg/24 hr OR 2.5-7.5 mmol/24 hr

FAQs

Q: What does it mean when there's calcium in your urine?

A: Calcium in the urine (hypercalciuria) means excess calcium is being lost in urine. Causes include high dietary calcium or vitamin D, primary hyperparathyroidism, certain medications, bone breakdown, or kidney problems. It’s often asymptomatic but raises risk of kidney stones and blood in urine. Diagnosis uses blood tests and a 24‑hour urine collection; treatment targets the underlying cause, dietary changes, hydration, and sometimes medications.

Q: What is the normal range of calcium in urine?

A: Normal urinary calcium excretion is generally reported as about 100–300 mg per 24 hours (≈2.5–7.5 mmol/24 h) in adults. Values above this suggest hypercalciuria; significantly lower values may indicate hypocalciuria. Spot urine calcium/creatinine ratios use different cutoffs, so interpretation depends on whether a 24‑hour collection or a spot sample was used.

Q: How to treat calcium in urine?

A: Treating high urinary calcium (hypercalciuria) focuses on preventing stones and correcting causes: drink plenty of fluids; cut dietary sodium and excess animal protein; keep normal—not low—dietary calcium; limit high-oxalate foods if stone risk. Doctors may prescribe thiazide diuretics or potassium citrate and investigate/treat causes (primary hyperparathyroidism, vitamin D excess). Regular urine testing and specialist review guide long-term therapy.

Q: What increases urinary calcium?

A: Increased urinary calcium (hypercalciuria) results from greater calcium absorption, bone resorption, or reduced renal reabsorption. Causes include high dietary sodium and animal protein, excess vitamin D or calcium supplements, hyperparathyroidism, certain malignancies, prolonged immobilization, loop diuretics, renal tubular disorders, and stimulants like caffeine. These factors raise calcium excretion and increase risk of kidney stones and bone loss.

Q: What cancers cause high calcium in urine?

A: Cancers that commonly cause high urinary calcium (from hypercalcemia) include breast cancer and other tumors that metastasize to bone, multiple myeloma, squamous‑cell lung carcinoma (often secreting PTH‑related peptide), and some lymphomas. Renal cell carcinoma and other PTHrP‑producing tumors can also raise blood and urine calcium. Evaluation should include serum calcium, PTH/PTHrP testing and cancer workup.

Q: Can high calcium cause UTI?

A: High blood calcium (hypercalcemia) does not directly cause a urinary tract infection, but it can increase UTI risk indirectly. Excess calcium promotes kidney stones, urinary stasis and altered urine composition, which can obstruct flow and harbor bacteria. If you have high calcium, recurrent UTIs, or symptoms such as pain, fever, or changes in urine, consult a healthcare provider for evaluation and management.