Abstract
In a cross-sectional survey 624 schoolchildren were screened for plasma calcium, inorganic phosphate, and alkaline phosphatase levels. Plasma magnesium and alkaline phosphatase isoenzymes were also estimated in some cases.No significant difference was found between adult and childhood values for calcium and magnesium. Levels of alkaline phosphatase and inorganic phosphorus varied with both age and sex. The magnitude of these variations in normal ranges is of clear importance in assessing data from individual paediatric or adolescent patients.