Folate deficiency in polycythaemia rubra vera.
D000748:Anemia, Macrocytic / Q000209:etiology*; D005365:FIGLU Test; D005494:Folic Acid Deficiency / Q000150:complications*; D006801:Humans; D008875:Middle Aged; D011087:Polycythemia Vera / Q000150:complications*; D014806:Vitamin B 12 Deficiency / Q000209:etiology