Evaluating the role of the Bristol stool chart in diagnosing functional constipation in pediatric populations

Figure 1 Flowchart of study enrollment. PPV: Positive predictive value; NPV: Negative predictive value; LR: Likelihood-ratio; CNS: Central nervous system; GI: Gastrointestinal.

Figure 2 Bristol stool chart. Type 1 separate hard lumps, like nuts, type 2 sausage-shaped but lumpy, type 3 like a sausage but with cracks on the surface, type 4 like a sausage or snake, smooth and soft, type 5 soft blobs with clear-cut edges, type 6 fluffy pieces with ragged edges, a mushy stool, type 7 watery, no solid pieces.

Figure 3 Diagnosis of functional constipation using the Rome IV criteria as the reference standard, with calculation of the area under the curve for Bristol stool chart. AuROC: Area under the receiver operating characteristic; CI: Confidence interval.