[Folic acid levels in patients with compensated renal failure and during long-term haemodialysis (author's transl)].

Folic acid concentration in plasma and erythrocytes and vitamin B12 concentration in plasma were determined by radioassay in 56 patients with chronic renal failure. Compensated retention was present in 31, while 25 were haemodialysed at regular intervals, 14 at home, and 11 in hospital. One patient had megaloblastic anaemia. Mean folic acid concentration in plasma for the whole group was 4.60 microgram/l (normal 8.30 +/- 2.57 microgram/l), in RBC 385 microgram/l (normal 459 +/- 143 microgram/l. Vitamin B12 levels were normal. These was no significant difference in folic acid levels betwwen patients on home or on hospital dialysis. During dialysis there was a fall in folic acid concentration in plasma which was proportional to the intial levels. After a four-week replacement pause folic acid concentration in RBC had not decreased in those patients on long-term dialysis who had previously received folic acid. The decreased folic-acid concentration in plasma of patients in compensated chronic renal failure is not due to the renal failure. Folic acid concentration in RBC is decisive in the assessment of folic acid deficiency.