Interpretation
Hypercalciuria increases the risk of developing kidney stones. Urine calcium measurement is included as part of a “stone screen” in patients with unexplained nephrolithiasis or nephrocalcinosis. Because of the large intra-individual variation in urinary calcium excretion, it is recommended to measure urine calcium on several separate timed urine collections.
Urine calcium measurement may also be measured to calculate the fractional excretion of calcium (FECa) in patients with hyperparathyroidism. FECa is elevated in patients with primary hyperparathyroidism, but is low in patients with familial hypocalciuric hypercalcaemia (FHH).
Causes of hypercalciuria include hyperparathyroidism, type 1 renal tubular acidosis, Paget’s disease, malignancy, prolonged immobilisation and autosomal dominant hypocalcaemia.
Causes of hypocalciuria include FHH and thiazide diuretics.
Test Method
Performed on Beckman Coulter AU5822 analyser using Beckman Coulter reagents.