Fecal calprotectin (FC) levels correlate with clinical or endoscopic activity in ulcerative colitis (UC), however, these values vary widely between detection methods, and optimal cut-off values remain debated. To assess the correlation between FC levels measured by fluorescent immunochromatography assay (FICA) and disease activity and to identify optimal cut-off values for predicting clinical and endoscopic activity in UC. The study included patients hospitalized at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology between January 2021 and June 2022. All the patients had a confirmed diagnosis of UC. Clinical activity was determined using the partial Mayo score (pMS), and endoscopic activity was determined using the ulcerative colitis endoscopy index of severity (UCEIS) and Mayo endoscopic score (MES). In 110 patients with UC, FC levels were significantly correlated with pMS (r = 0.609, P < 0.001), UCEIS (r = 0.751, P < 0.001) and MES (r = 0.635, P < 0.001). Moreover, the optimal FC cut-off values to predict clinical activity (pMS 3-12) and endoscopic activity (UCEIS 1-8 or MES 1-3) were 57.38 µg/g and 53.30 µg/g, respectively. FC measured by FICA was a good predictor of clinical and endoscopic activity in patients with UC. When using FICA to detect FC, the optimal cut-off value to identify clinical activity in patients with UC was 57.38 µg/g, and a lower value should be chosen to optimize the identification of endoscopic activity in these patients, which was determined as 53.30 µg/g.
Xu et al. (2025) studied this question.