The novel latex agglutination turbidimetric immunoassay system for simultaneous measurements of calprotectin and hemoglobin in feces

BACKGROUND/AIMS: Fecal calprotectin (Fcal) as well as the fecal immunochemical test (FIT) are useful biomarkers for detecting activity and mucosal healing in inflammatory bowel diseases. Here, we report the performance of simultaneous measurements of Fcal and FIT for ulcerative colitis (UC) patients using the newly-developed latex agglutination turbidimetric immunoassay (LATIA) system. METHODS: Fcal and hemoglobin were measured by the LATIA system in 152 UC patients who underwent colonoscopy. Fcal was also quantified with a conventional enzyme-linked immunosorbent assay (ELISA). Fecal markers were evaluated in conjunction with the mucosal status of UC, which was assessed via the Mayo endoscopic subscore (MES) classification. RESULTS: The LATIA system could quantify calprotectin and hemoglobin simultaneously with the same fecal samples within 10 minutes. The values of the Fcal-LATIA closely correlated with those of the Fcal-ELISA (Spearman rank correlation coefficient, r=0.84; P<0.0001). The values of Fcal for each assay and the FIT all significantly correlated with the MESs (Spearman rank correlation coefficient, Fcal-LATIA: r=0.58, Fcal-ELISA: r=0.55, and FIT: r=0.72). The mucosal healing predictability (determined by an MES of 0 alone) of the Fcal-LATIA, Fcal-ELISA, and FIT-LATIA with the cutoffs determined by receiver operating characteristic curve analysis was 0.79, 0.78, and 0.92 for sensitivity, respectively, and 0.78, 0.69, and 0.73 for specificity, respectively. CONCLUSIONS: The performance of the novel Fcal-LATIA was equivalent to that of the conventional Fcal assay. Simultaneous measurements with FITs would promote the clinical relevance of fecal biomarkers in UC.

Fecal Immunochemical Test and Fecal Calprotectin Results Show Different Profiles in Disease Monitoring for Ulcerative Colitis

BACKGROUND/AIMS: Both fecal immunochemical test (FIT) and fecal calprotectin (Fcal) results are useful biomarkers for ulcerative colitis (UC). However, the situations in which each marker should be used are largely unknown. METHODS: A total of 110 colonoscopy intervals of UC patients were assessed, and correlations between changes in colonoscopic findings and changes in the two aforementioned fecal markers were examined. RESULTS: Among patients with mucosal healing (MH) and negative FIT or Fcal results at the initial colonoscopy, FIT and Fcal findings exhibited accuracies of 93% (38/41) and 79% (26/33), respectively, for predicting the results of the subsequent examination. Among the 24 patients who showed endoscopic activity at the precedent colonoscopy and MH at the subsequent examination, positive-to-negative conversion of FIT and Fcal findings at the subsequent examination was observed in 92% (12/13) and 62% (8/13) of patients, respectively. Among the 43 patients who showed endoscopic activity at both the precedent and subsequent examinations, Fcal findings reflected the change in endoscopic activity better than FIT results (r=0.59, p<0.0001 vs r=0.30, p=0.054). CONCLUSIONS: The FIT is useful for confirming MH and the occurrence of relapse. In contrast, Fcal is useful for monitoring the mucosal status of patients with active inflammation.

An Elevated Platelet Count Increases the Risk of Relapse in Ulcerative Colitis Patients with Mucosal Healing

BACKGROUND/AIMS: Although mucosal healing (MH) has been considered a treatment goal for patients with ulcerative colitis (UC), the risk factors predictive of relapse in patients who achieve MH are unknown. Because the platelet count has been shown to be a marker of inflammation in inflammatory bowel diseases, this study aimed to assess whether the platelet count could predict relapse in UC patients with MH. METHODS: A prospective observational study was performed. UC patients with MH were consecutively enrolled in the study and monitored for at least 2 years or until relapse. The correlation between the incidence of relapse and the platelet count at the time of study enrollment was examined. RESULTS: In total, 43 patients were enrolled, and 14 patients (33%) relapsed. The median platelet count at the time of enrollment in the patients who relapsed significantly differed from that in the patients who did not relapse (27.2×104/μL vs 23.8×104/μL, respectively; p=0.016). A platelet count >25.0×104/μL was a significant risk factor for relapse based on a multivariate analysis (hazard ratio, 4.85; 95% confidence interval, 1.07 to 25.28), and according to the Kaplan-Meier analysis, this cutoff could identify patients susceptible to relapse (p=0.041, log-rank test). CONCLUSIONS: The platelet count could be used as a predictor of relapse in UC patients with MH.