Claim: In longitudinal UC monitoring, a sustained increase in the stool succinate:butyrate ratio precedes clinical flare and fecal calprotectin rise by ~3–7 days.

Rationale: Succinate can amplify inflammatory signaling, while butyrate supports epithelial barrier and Treg tone. A ratio metric may capture a directional ecological shift earlier than absolute single-metabolite thresholds.

Test design: Daily home stool metabolomics + weekly calprotectin in a prospective cohort, with mixed-effects lead-lag models and patient-level baselines. Compare ratio-triggered alerts vs calprotectin-only thresholds for early-warning sensitivity at fixed false-alert rate.

Falsification criterion: If the ratio does not show consistent positive lead (>=3 days median) over calprotectin across external validation cohorts, this hypothesis is rejected.

Discussion question: Which covariate is most critical to lock first for transportability across sites—dietary fiber intake, recent antibiotic exposure, or stool water content normalization?