Chapter 4: Scores for Inflammatory Bowel Disease 4.1 Clinical and endoscopic scoring systems in IBD Statement 4.1.ECCO-ESGAR Diagnostics GL (2018) Clinical indices are useful for standardizing disease activity.However, despite widespread use, no score has been validated in clinical practice [EL5] Clinical and endoscopic scoring systems in ulcerative colitisThere are several scoring systems presently available to classify disease severity in ulcerative colitis (UC) within the multiple domains of disease activity, which aid objective assessment of disease and guide therapeutic and monitoring strategies [1,2].Although somewhat limited by subjective definitions, their strength lies in the potential to monitor patient progress over time [1].The Simple Colitis Clinical Activity Index (SCCAI) [2, 3] and the Paediatric Ulcerative Colitis Activity Index (PUCAI) [4] are reliable and responsive scores with clear definitions for clinical response and remission (see Tables).SCCAI scores range between 0 and 19 points and include nocturnal bowel movements and faecal urgency, which affect patient quality-of-life (QoL) [3].An SCCAI score <2 indicates clinical remission and a decrease of >1.5 points from baseline correlates with patient-defined significant improvement [5].The Mayo Clinic Index (Partial Mayo Clinic Index and endoscopic subscore) and Ulcerative Colitis Disease Activity Index (UCDAI) are a composite assessment of clinical symptoms (stool frequency and rectal bleeding) and endoscopic severity (Table x) [6,7].While these indices are not validated, the Mayo Clinic Index is easy to apply and has been used for assessing therapeutic endpoints in adult clinical trials [8].Clinical improvement is defined as the reduction of baseline scores by ≥3 points and clinical remission as an overall score ≤2 (and no individual subscore >1) or UCDAI ≤1 [6][7][8].A Partial Mayo Score (PMS) <1 indicates remission [1].The PMS has been shown to correlate well with the full scoring system [9,10].The Truelove and Witts Severity Index was described in 1955 [11].Its elements reflect levels of systemic toxicity and provide objective criteria for assessment of acute severe colitis, need for hospitalization, and corticosteroid therapy [2] (Table y).The Lichtiger Index is a Supplementary Table 3. Disease activity in ulcerative colitis, adapted from Truelove and Witts [11] Mild Moderate 'between mild and severe' Severe Bloody stools/day