Serum 25-hydroxycholecalciferol in Greek uremics

Using a simplified competitive protein-binding assay, we measured serum 25-hydroxycholecalciferol (25-OH-D3) in 52 patients with chronic renal failure and in 21 normal subjects. Of the patients with chronic renal failure, 21 were undergoing hemodialysis. Low serum levels of 25-OH-D3 were found in nondialysis patients and normal levels in the dialysis group. A positive relationship between the levels of 25-OH-D3 and serum calcium and a negative relationship between the levels of 25-OH-D3 and serum creatinine were found in the nondialysis group. We postulate that the decreased 25-OH-D3 levels in chronic uremics is the result of the low level of vitamin D in their protein-restricted diets.