The 66 (age 101.1+58.9 months) leukemia cases admitted to our clinic were evaluated for the frequency of pre-treatment folic acid, vitamin B12 (VB12) and 25-hydroxy vitamin D (25-OH VD) deficiency/excess. In the patient group, folic acid (6.9 ± 6.2 vs. 9.5 ± 4.5, p = 0.0001 respectively) and 25- OH VD (19.5 ± 17.8 vs. 23.8 ± 16.7 μg/L, p= 0.042) were lower than the control while the ratio of patients who had low (18.5% vs. 0%, p = 0.001) and high (4.6% vs. 0%, p = 0.001) folic acid, low VB12 (12.1% vs. 0%, p = 0.012) and very low 25-OH VD (<10 mg/L) (34.4% vs. 0%; p = 0.021) were higher than the control. The ratios of patients who had high levels of VB12 were lower (19.7% vs. 34.7%, p = 0.012). No apparent relationship seemed between the risk of leukemia and the deficiency /excess of the parameters. Replacement therapy (VB12 and folic acid) was administered after achievement of remission. Both patients who did not achieve remission, had both folic acid and VB12 deficiency. Our data, accentuates the importance of such a pre-treatment screening in leukemia patients.

Keywords: <i>çocukluk çağı lösemisi, folik asit, vitamin B12, 25-hidroksi vitamin D, remisyon.</i>