Evaluation of the possibility of using fecal calprotectin for the diagnosis of inflammatory bowel diseases in patients with ankylosing spondylitis

The aim . To evaluate the possibility of using fecal calprotectin levels for early diagnosis of inflammatory bowel diseases in patients with AS in real clinical practice. Materials and methods . The analysis included 70 patients with a confirmed diagnosis of AS over the age of 18: 52 men (74.3 %) and 18 women (25.7 %), aged 47.4±8.8 years, with a disease duration of 19.6±7.9 years. All patients underwent blood tests (ESR, CRP, HLAB 27 antigen levels), esophagogastroduodenoscopy and colonoscopy, quantitative analysis of the fecal calprotectin levels using the method of lateral immunochromatography with the BUHLMANN Quantum Blue rapid test (standart range: 100–1800 μg/g). Results . All patients had high disease activity: BASDAI was 5.4±1.4, ASDAS CRP – 3.6±0.8. IBD was diagnosed in 18 cases (25.7 %). In 77 % of patients with AS, the FC level exceeded 100 μg/g, and in 28 % it exceeded 1800 μg/l. The FC level was more than 1000 μg/g in 63 %. In patients with IBD, the FC level was more than 100 μg/g, and the average FC level was higher in patients with IBD (1141.3 μg/g) than without IBD (787 μg/g). No active IBD was detected in all patients with FC levels less than 300 μg/g of feces. FC levels correlated with CRP (r=0.366) and ESR (r=0.366) (p<0.001). A positive HLAB 27 antigen was found in all patients with IBD. Conclusion . Patients with AS and IBD had higher FC levels than patients without IBD. Normal FC levels in patients with AS indicate the absence of intestinal inflammation. There was also a correlation between increased FC levels and the severity of AS. According to the study, measuring fecal calprotectin levels may be useful for detecting intestinal inflammation at an early stage.