Department of Gastroenterology, Glasgow Royal Infirmary, Glasgow, UK.
Aliment Pharmacol Ther. 2013 Mar;37(6):613-21. doi: 10.1111/apt.12221. Epub 2013 Jan 24.
As a non-invasive marker of gastrointestinal inflammation, faecal calprotectin (FC) is being increasingly used to guide the management of Crohn's disease. It is therefore a concern that studies have shown variability in day to day levels.
To determine the degree of this intrapersonal variability in the context of quiescent Crohn's disease.
A single-centre prospective study was undertaken in 143 Crohn's disease patients in clinical remission. Three faecal calprotectin levels were analysed from stool samples on consecutive days. Consistency of faecal calprotectin levels was determined by measuring the intraclass correlation (ICC). Due to higher variability at higher faecal calprotectin levels, the ICC was calculated for the log-transformed values. The reliability of detecting a 'case' of active inflammation as defined for specific concentrations of faecal calprotectin was measured by the kappa statistic.
Ninety-eight complete sets of results were obtained. The ICC was 0.84 (95% CI: 0.79-0.89), which represents low variability across samples. The kappa statistic for the reliability of detecting a case as defined by an FC level of >50 μg/g was substantial at 0.648 (0.511-0.769).
Day to day variability of faecal calprotectin is low in our cohort of quiescent Crohn's disease patients and the reliability of defining a 'case' is moderately good. These data provide reassurance to clinicians using a single calprotectin sample to inform therapeutic strategies in this cohort.
粪便钙卫蛋白（FC）作为胃肠道炎症的非侵入性标志物，正越来越多地用于指导克罗恩病的管理。因此，令人担忧的是，研究表明其日常水平存在变异性。
在克罗恩病缓解期患者中，确定其个体内变异程度。
在 143 例处于临床缓解期的克罗恩病患者中进行了一项单中心前瞻性研究。对连续 3 天的粪便样本进行了 3 次粪便钙卫蛋白水平分析。采用组内相关系数（ICC）来确定粪便钙卫蛋白水平的一致性。由于粪便钙卫蛋白水平越高，变异越大，因此对其进行了对数转换值的 ICC 计算。采用 Kappa 统计来衡量检测特定浓度粪便钙卫蛋白定义的“活动”炎症“病例”的可靠性。
获得了 98 套完整的结果。ICC 为 0.84（95%CI：0.79-0.89），表明样本间的变异度较低。根据 FC 水平＞50 μg/g 定义的病例检测可靠性的 Kappa 统计值为 0.648（0.511-0.769），具有中度可靠性。
在我们的克罗恩病缓解期患者队列中，粪便钙卫蛋白的日常变异度较低，定义“病例”的可靠性适中。这些数据为使用单个钙卫蛋白样本为该队列提供治疗策略的临床医生提供了保证。
