Hypophosphataemia and hyperphosphataemia in a hospital population.

One hundred cases of hypophosphataemia (</= 2.0 mg/100 ml) and 84 cases of hyperphosphataemia (>/= 5.0 mg/100 ml) occurring in a hospital population were studied in order to determine the cause of the abnormality. Examples of hyperphosphataemia due to renal failure were excluded from the study.A low serum phosphorus concentration was most frequently due to intravenous administration of carbohydrate, usually glucose, which accounted for 40% of cases. The next commonest cause was vomiting (12%). No obvious explanation could be found in 26% of cases, but in most of these factors were present which are known to affect phosphorus metabolism.No one cause of hyperphosphataemia was outstanding in frequency and in over 50% of cases no definite explanation for the abnormality could be found.