Complete blood count derived indices for dietary follow up in children with celiac disease

Monitoring adherence to a GFD remains a central challenge in the long-term management of pediatric celiac disease (CD). Although serological markers are widely used, their cost and limited availability may restrict frequent monitoring in some settings. Routine complete blood count (CBC)–derived indices may provide additional, low-cost information to support dietary follow-up. In this multicenter retrospective longitudinal cohort study, 163 children with CD who had available laboratory data at diagnosis and after 12 months of a GFD were compared with 187 age-matched children with functional constipation serving as the control group. CBC-derived indices, including mean platelet volume (MPV), platelet-to-lymphocyte ratio (PLR), and red cell distribution width–to–platelet ratio (RPR), were assessed at diagnosis and after 12 months of a GFD. Dietary adherence was evaluated using tissue transglutaminase antibody (tTG) levels. Receiver operating characteristic (ROC) analyses were performed to determine the discriminative ability and optimal cut-off values of CBC-derived indices. Longitudinal changes and correlations with serological response were analyzed, and a practical CBC-based decision-flow approach was constructed. At diagnosis, MPV was significantly lower and PLR significantly higher in children with CD compared with controls ( P < 0.05). After 12 months of a GFD, MPV and RPR increased, while PLR decreased significantly (all P < 0.01). MPV showed a moderate inverse correlation with tTG levels both at baseline and over time. ROC analysis identified MPV as the most informative individual index (AUC 0.73). An optimal cut-off value of < 9.3 fL yielded 100% specificity and 48% sensitivity for identifying serological positivity. A combined model incorporating MPV, PLR, and RPR showed improved discriminative performance. Based on these findings, a simple CBC-based flow diagram was constructed to support dietary follow-up when serological testing is unavailable. CBC-derived indices demonstrate consistent longitudinal changes during GFD follow-up in children with CD. While not replacing serological markers, MPV—particularly when interpreted alongside PLR and RPR—may serve as a supportive, low-cost adjunct for dietary follow-up, supported by defined cut-off values and a practical clinical decision-flow approach.