Serial measurements of faecal calprotectin may discriminate intestinal tuberculosis and Crohn’s disease in patients started on antitubercular therapy

Response to antitubercular therapy (ATT) is often used to differentiate intestinal tuberculosis (ITB) from Crohn's disease. Role of non-invasive biomarkers to predict mucosal response to ATT is unclear.A prospective study to compare faecal calprotectin and serum C-reactive protein (CRP) levels at diagnosis, 2 and 6 months of ATT in patients with suspected ITB started on ATT was done. The patients were eventually divided into two groups: ITB or alternative diagnosis (OTH). Decline of calprotectin and CRP levels was used to compute area under the receiver operating characteristic (AUROC) to predict mucosal healing at 2 months.Thirty-seven patients (mean age: 34.95 ± 16.35 years, 23 males) were included and 28 (75.67%) were diagnosed as ITB while nine (24.32%) had alternative diagnosis (OTH). The median faecal calprotectin values of ITB and OTH groups at baseline, 2 months and 6 months were 216 and 282 µg/g (P = 0.466), 43 and 216 µg/g (P = 0.003), and 26 and 213 µg/g (P < 0.001), respectively. The median CRP values at baseline, 2 months and 6 months were 18 and 30 mg/L (P = 0.767), 4.7 and 15 mg/L (P = 0.025), and 3 and 10.85 mg/L (P = 0.068), respectively. The AUROC of percent decline in faecal calprotectin and serum CRP at 2 months for mucosal healing were 0.8287 [95% confidence inteval (CI) 0.6472-1] and 0.6018 (95% CI 0.4079-0.7957), respectively.Faecal calprotectin can help in assessing response to therapy in suspected ITB patients started on empirical ATT.