Continuous reference intervals for holotranscobalamin, homocysteine and folate in a healthy paediatric cohort

Background :The detection of deficiencies in B12 and folate children is important. However, despite the availability of various markers to assess B12 and folate metabolism, there are limited studies describing the reference intervals (RIs) and changes during growth and development for these markers in healthy children. Methods: Using samples collected from 378 children aged 30 days-< 18 years, we derived continuous RIs for holotranscobalamin, homocysteine and red cell folate. Results: The lower RI for holotranscobalamin was lowest at birth, rising during early childhood and then declining following ages 4-6 years whereas red cell folate was highest early in life and then declined steadily towards adulthood. Total homocysteine, reflective of both B12 and folate status was elevated early in life, reaching a nadir at age 2 and then increasing towards adulthood. Conclusions: Continuous central 95(th) percentile RI for holotranscobalamin, homocysteine and red cell folate for children ages 30 days to <18 years were established. Each marker shows dynamic changes throughout childhood and adolescence which will assist clinicians in more appropriately assessing B-12 and folate status in this population.