[Diagnosis of vitamin B12 deficiency in chronic kidney insufficiency].

It is difficult to assess the vitamin B12 metabolism in chronic renal insufficiency. In varying numbers out of a total of 88 nephropathy patients with varying degrees of insufficiency (22 patients without restriction of kidney function, 53 patients with chronic renal insufficiency in the stage of compensated retention and 13 haemodialysis patients) the Schilling test was performed and the serum vitamin B12 level was measured in fasting and 4, 6, 8 and 10 hours after oral administration of 2000 micrograms of vitamin B12. Regardless of the volume of urine, the Schilling test must be treated critically with serum creatinine values between 150 and 300 mumol/l and beyond 300 mumol/l it is no longer of diagnostic value. Serum vitamin B12 measurement after oral administration of 2000 micrograms of vitamin B12 allows vitamin resorption in the ileum to be qualitatively demonstrated on the basis of the curve. In most renal insufficiency patients the serum vitamin B12 level was increased, but this does not exclude the possibility of vitamin B12 deficiency.