Bone & Mineral Metabolism

Convert total calcium between mg/dL, mmol/L, mEq/L and mg/L — and get the divalent step right, because mEq/L is twice the mmol/L figure, not the same as it.

Separate familial hypocalciuric hypercalcaemia from primary hyperparathyroidism using the 24-hour calcium-creatinine clearance ratio.

Adjust total serum calcium for a low albumin using the traditional correction formula, and see why it should not be trusted alone in sick patients.

Convert a calcium salt dose to its elemental calcium content — the figure that dosing guidelines and prescriptions actually specify.

Convert intact PTH between pg/mL, pmol/L and ng/L, and see why a PTH from one laboratory cannot be compared with a PTH from another.

Convert serum phosphate between mg/dL, mmol/L and mg/L — and see why the factor uses the atomic weight of phosphorus rather than that of phosphate.

Convert a potassium salt dose in milligrams to mmol (equal to mEq for this monovalent ion), across the common oral salts.

Calculate the renal tubular maximum phosphate reabsorption threshold (TmP/GFR) using the Walton-Bijvoet formula, the most sensitive test for renal phosphate wasting.

Convert vitamin D doses between international units and micrograms, and see how dosing relates to the measured 25-hydroxyvitamin D level.