Whole blood folate values in pernicious anaemia: relation to treatment.

27 patients with pernicious anaemia, followed for a long period, were consecutively treated with three different vitamin B12 preparations, while during intervening period no therapy was given until signs of B12 deficiency developed. After vitamin B12 treatment, a peak whole blood folate value some 70% higher than the starting value was noted after about 75 d in patients treated with B12 injections and after about 165 d in perorally treated patients. During the same time significantly increased whole blood folate/plasma folate ratio was noted. In most of the patients, whole blood folate declined from peak to plateau level in about 150 d and thereafter remained almost unchanged until signs of cobalamin deficiency developed. The mean time from peak to plateau values was significantly longer in "long-reactors" than in "short-reactors". Higher peak and plateau values were noted in patients with neuropathy and mucosal symptoms, as compared to patients with hypersegmentation.