Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (772 page)

   Hypomagnesemia (e.g., due to cisplatin chemotherapy)

   Hyperphosphatemia (e.g., laxatives, phosphate enemas, chemotherapy of leukemia or lymphoma, rhabdomyolysis)

   Hypoalbuminemia

   Hemodilution

CALCIUM, URINE

   Definition

   Urinary calcium levels reflects intake, rates of intestinal calcium absorption, bone resorption, and renal loss. Hypercalcemia of any cause raises urinary calcium excretion, and its measurement adds little to the differential diagnosis of hypercalcemia. Fasting calcium excretion is useful when assessing the contribution of abnormal renal tubular handling of calcium to disorders of calcium homeostasis.

   
Normal range:

   Twenty-four–hour urine: 100–300 mg/day

   Random urine:

   Males: 12–244 mg/g creatinine

   Females: 9–328 mg/g creatinine

   Use

   Evaluation of patients with disorders of bone disease, calcium metabolism, and renal stones