Relationship Between Stool Color and Serum Direct Bilirubin in Children with Biliary Atresia

Abstract

Objective: Stool color inspection is a simple tool for monitoring outcomes of biliary atresia (BA). Aim of this study was to identify a correlation between stool color and serum direct bilirubin (DB) among BA and evaluate agreement of color inspection between groups of medical providers.

Materials and Methods: Prospective data collection was performed in 110 BA patients who admitted in Division of Pediatric Surgery for various conditions. Stool color card was created using standard CMYK system and was arranged as level of yellow color composition. Stool inspection was calibrated using stool color card and was performed when blood test for DB was ordered. Data analysis was performed using Spearman’s correlation coefficient, Fisher's Exact test, Diagnostic test, AUROC and Cohen’s weighted kappa.

Results: The overall correlation between intensity of yellow color in stool and DB was statistically significant inverse (r = - 0.31, p<0.05). When the intensity of yellow color was graded as level 1-5, there was statistically different between groups in term of detection of abnormal DB (p-value = 0.006). Five levels of intensity were grouped to find the best cut-point for abnormal DB. Children who had stool color level 1-4 could predict abnormal DB as sensitivity as 72%, specificity as 71% and AUROC as 0.73. There was almost agreement of color inspection of the same specimen between group of doctors(D), nurse(N) and practical nurse (PN).

Conclusion: Stool color card could be used as a standardized tool to assess among healthcare providers. Stool color inspection and calibrated with stool color card could be applied as a screening tool for abnormal serum DB. Patients who had stool color level 1-4 should be further assessed the blood test for liver function.