Vitamin B12 and folate : pediatric reference ranges

Pediatric reference ranges were obtained for vitamin B 12 and folate (Quantaphase radioimmunoassay, BioRad, Hercules, Calif) using a large hospital population. Data were analyzed employing the Hoffman approach, which was computer adapted. For folic acid, the range for subjects aged 1 to 12 years averaged 5.7 to 31.3 nmol/L for female subiects and 4.5 to 27.0 nmol/L for male subjects. There was a significant decrease in folic acid concentrations after 13 years, the upper limit being 16.5 nmol/L in female subiects and 19.9 nmol/L in male subiects. For vitamin B 12 , the values in the 0- to 1 -year age group were nearly double those in the 13- to 18-year age group