Calcium urine

Keywords: Urine calcium

Specimen:

24 h urine collection with HCl as preservative - consult pathologist.

Fasting morning spot urine (2nd void).

Method:

Spectrophotometry or atomic absorption spectrophotometry.

Reference Interval:

2.5-7.5 mmol/24 h

Fasting spot urine:

Males: 0.04-0.45 mol/mol creatinine

Females: 0.10-0.58 mol/mol creatinine

Application:

Usually for investigation of renal calculi.

Diagnosis of hypocalciuric Hypercalcaemia - 24 h urine calcium/creatinine clearance ratio < 0.01.

Interpretation:

Increased excretion seen with high dietary intake of calcium, increased mobilisation of calcium from bone, and most conditions associated with Hypercalcaemia.

Hypercalciuria is a risk factor for renal calculi.

Reference:

Pak CYC. Urologic Clin N Amer 1981; 8: 243-252.

Marx SJ. N Engl J Med 2000; 343(25): 1863-1875.