P404 Monocyte distribution width differentiates bacterial gastroenteritis from Acute Severe Ulcerative Colitis in patients presenting with diarrhoea

Abstract Background Monocyte distribution width (MDW) is a haematological parameter that can be generated by newer generation blood analysers on routine full blood examination. It reflects the variation in the size of monocytes and is elevated in the setting of infection, however its utility in inflammatory disorders in unknown. We aimed to assess whether MDW can help differentiate bacterial gastroenteritis from Acute Severe Ulcerative Colitis (ASUC) among patients presenting to the Emergency Department (ED) with diarrhoea. We further aimed to assess whether MDW correlated with disease activity and clinical outcomes in ASUC. Methods We conducted a retrospective cohort study comprising three patient groups: (1) ASUC, (2) bacterial gastroenteritis and (3) a control group of patients without active inflammation. The control group consisted of outpatients with chronic hepatitis B in immune control phase with normal liver transaminases and suppressed viral load < 2000 IU/mL. Clinical outcomes, routine biomarkers and MDW were recorded. Results A total of 176 patients were identified (53 ASUC, 70 bacterial gastroenteritis and 53 controls). At time of ED presentation, patients with bacterial gastroenteritis had the highest MDW (median 23.6, IQR 20.7-25.8) compared to ASUC (19.0, IQR 17.9-21.2) and controls (16.8, IQR 15.9-18.0; P