摘要目的:比较酶联免疫吸附分析（ELISA）与荧光免疫层析法（FICA）检测的粪钙卫蛋白（FC）在炎症性肠病（IBD）活动性评估中的诊断效能与一致性。方法:采用配对设计的诊断试验比较研究方法。前瞻性纳入西安交通大学第二附属医院2025年5—6月同步接受ELISA与FICA检测的61例IBD患者。以Best克罗恩病活动指数和改良Mayo评分为金标准，通过受试者工作特征（ROC）曲线确定FC评估活动性的最佳截断值。采用Spearman相关、Passing-Bablok回归和Bland-Altman分析评估数值一致性。基于厂商标准（ELISA为200 μg/g、FICA为100 μg/g）与自定义截断值计算Cohen's Kappa系数，评估分类一致性。结果:61例患者中，男性28例，女性33例；年龄48（34，61）岁；病程48（12，109）个月；溃疡性结肠炎43例，克罗恩病18例；缓解期35例，活动期26例；ELISA检测FC为178.0（30.0，1 342.0）μg/g，FICA检测FC为67.2（15.0，275.6）μg/g。ELISA测得FC诊断IBD活动性的曲线下面积（AUC）为0.930，最佳截断值为154.0 μg/g时敏感度为80.0%，特异度96.2%；FICA诊断活动性的AUC为0.784，最佳截断值为81.2 μg/g时敏感度为80.0%，特异度80.8%。DeLong检验结果提示ELISA的综合诊断效能明显优于FICA，差异具有统计学意义（ Z = 2.550， P = 0.011）。Spearman相关性分析发现，ELISA和FICA测得的FC数值相关系数为0.62（95% CI：0.41~0.73， P<0.001）。Cusum线性检验提示2种方法检测结果呈线性关系（ P = 0.291）。Passing-Bablok回归分析发现，回归拟合方程y = -53.38 + 5.56x，ELISA和FICA存在显著的固定和比例系统误差，且误差随浓度升高而增大。Bland-Altman分析显示，ELISA检测值系统性高于FICA（总体平均偏倚：74.5%，95%一致性界限：-101.0%~250.0%），且活动期的差异比缓解期差异更明显（平均偏倚：100.4%比48.0%）。基于ROC曲线分析的自定义截断值在分类一致性上较厂商截断值提升明显（Kappa：0.608比0.474）。 结论:ELISA与FICA对IBD活动性均有较好的诊断价值，但存在浓度依赖性系统误差（ELISA>FICA）。推荐临床固定使用同一方法监测病情，并采用自定义截断值优化活动性分层准确性。

abstractsObjective:To compare the diagnostic efficacy and consistency of fecal calprotectin (FC) detected by enzyme-linked immunosorbent assay (ELISA) and fluorescence immunochromatography assay (FICA) in assessing the disease activity of inflammatory bowel disease (IBD) .Methods:The paired-design diagnostic test comparison study was conducted. A total of 61 IBD patients from the Second Affiliated Hospital of Xi'an Jiaotong University who underwent simultaneous ELISA and FICA testing from May to June 2025 were prospectively enrolled. Using Best Crohn's disease activity index and modified Mayo score as gold standards, optimal FC cut-offs for assessing the disease activity were determined by receiver operating characteristic (ROC) curve analysis. Numerical consistency was evaluated via Spearman correlation, Passing-Bablok regression, and Bland-Altman analysis. Classification consistency was assessed by Cohen's Kappa coefficient based on both manufacturer-recommended cut-offs (ELISA: 200 μg/g, FICA: 100 μg/g) and ROC-optimized cut-offs.Results:Of the 61 patients, 28 were male and 33 were female, with a median age of 48 (34, 61) years and a disease duration of 48 (12, 109) months; 43 had ulcerative colitis (UC) and 18 had Crohn's disease (CD) ; 35 were in remission and 26 were in the active stage. Median FC concentrations were 178.0 (30.0, 1 342.0) μg/g by ELISA and 67.2 (15.0, 275.6) μg/g by FICA. The area under the curve (AUC) for ELISA in diagnosing activity of IBD was 0.930, with a sensitivity of 80.0% and specificity of 96.2% at the optimal cut-off of 154.0 μg/g. The AUC for FICA was 0.784, with a sensitivity of 80.0% and specificity of 80.8% at the optimal cut-off of 81.2 μg/g. DeLong test showed that the overall diagnostic efficacy of ELISA was significantly superior to that of FICA ( Z = 2.550, P = 0.011). Spearman correlation analysis showed a correlation coefficient of 0.62 (95% CI: 0.41-0.73, P < 0.001) between ELISA and FICA results. The Cusum linearity test indicated a linear relationship between the two methods ( P = 0.291). Passing-Bablok regression yielded the equation y = -53.38 + 5.56x, indicating both significant constant and proportional systematic errors between ELISA and FICA, and the errors increased with the concentrations. Bland-Altman analysis demonstrated ELISA assay values were systematically higher than those of FICA (overall mean bias: 74.5%, 95% limits of agreement: -101.0% to 250.0%), with larger differences in active disease than remission (the mean bias: 100.4% vs. 48.0%). Classification consistency improved markedly when using ROC-optimized cut-offs compared with manufacturer-recommended cut-offs (Kappa: 0.608 vs. 0.474) . Conclusions:Both ELISA and FICA can effectively identify active IBD but exhibit concentration-dependent systematic bias (ELISA > FICA). The consistent use of a single assay is recommended for disease monitoring and ROC-optimized cut-offs are adopted to improve the accuracy of disease activity stratification.