Clinical profile and utility of biomarkers in children with cobalamin (vitamin B12) deficiency: A cross-sectional study.

This article focuses on evaluating the utility of novel biomarkers in diagnosing clinical cobalamin (vitamin B12) deficiency in children. In a prospective cross-sectional study of 67 children aged 1 month to 18 years with suspected B12 deficiency, the combined index 4cB12—which integrates total B12, holotranscobalamin (HoloTC), methylmalonic acid (MMA), and homocysteine (Hcy)—was used as a reference standard for functional B12 status. Results showed that total B12 levels alone had low sensitivity (51%) for detecting deficiency, whereas HoloTC demonstrated higher sensitivity (87%), and combinations of low HoloTC with macrocytosis (high mean corpuscular volume) or abnormal peripheral smear improved sensitivity further (up to 94%). The study concludes that HoloTC, especially when combined with macrocytosis, may serve as a more sensitive and practical screening tool than total B12 levels alone, though further validation in larger, community-based pediatric populations is needed.