[Hematologic changes in patients under long-term hemodialysis and hemofiltration treatment with special reference to serum concentrations of folic acid and vitamin B 12].

The incidence of macrocytic anemia has been investigated in 32 patients on maintenance hemodialysis (mean age 46 years, mean duration of dialysis treatment 27.5 months), in 18 patients with combined hemodialysis (HD) and hemofiltration (HF) treatment (mean age 42 years, mean duration of combined HD and HF treatment 6.3 months) and in 32 patients after renal transplantation (mean age 41 years, mean observation period since successful renal transplantation 55.2 months). Also investigated were serum levels of vitamin B12 (radioassay kit 57Co) and folic acid (radioassay kit 125J). Macrocytosis (MCV greater than 96 fl) was observed in 38% of the patients on maintenance hemodialysis, in 44% of the patients with combined HD and HF treatment, and in 47% of the renal transplant recipients. In the chronically dialysed patients, in contrast to the patients with combined HD and HF treatment, the mean serum folic acid level was significantly lower (p less than 0.005) than that of healthy controls. Serum levels of vitamin B12 were within the normal range in all patients. There were no significant differences in serum levels of folic acid and vitamin B12 between the patients with MCV greater than 96 fl and MCV less than or equal to 96 fl. Nor was there a correlation between the serum levels of folic acid or vitamin B12 and mean corpuscular volume. These results suggest that folic acid deficiency is of minor importance in the complex pathogenesis of anemia in hemodialysed patients.