1. In a series of patients with sickle-cell anaemia, serum phosphate and magnesium concentrations were elevated. Serum calcium concentrations were normal. Urinary excretion of calcium was decreased.
2. The maximum tubular reabsorption of phosphate per litre of glomerular filtrate (TmP/GFR) was significantly increased in these patients.
3. The increase in phosphate reabsorption explains the elevated serum phosphate observed in these patients.