Fecal calprotectin levels in healthy controls and patients with ankylosing spondylitis. Absolute values of fecal calprotectin (fCAL) are shown in μg/g (y axis). Each square represents the fCAL level of an individual healthy control (HC) and each circle represents the fCAL of an individual patient with ankylosing spondylitis (AS). The highest measured level of fCAL in the control group was 104 μg/dl, while the highest observed level in the AS group was 1,085 μg/g.
Matzkies et al. Arthritis Research & Therapy 2012 14:R261 doi:10.1186/ar4106