Fecal Calprotectin Quantification Protocol

EliA^TM Calprotectin 2 (Phadia AB, Uppsala, Sweden) kits were used to measure FC levels. Fecal samples were collected at home or in a hospital. When collected at home, patients were instructed to refrigerate their fecal samples (2–8°C). The fecal samples were stored in aliquots at −20°C or below until analysis using the fluorescence immunoassay method per manufacturer's instructions was performed. The EliA Calprotectin 2 kit measures FC levels in the range of 3.8 – ≥ 6,000 μg/g. As stated by the manufacturer, the cutoff level of FC, representing a positive value, was ≥ 50 μg/g. Based on previous studies.^{[13 ,15 (link)]} the FC test results classified cases as follows: moderate to severe (>200 μg/g, >250 μg/g, or >300 μg/g), mild (100–200 μg/g, 100–250 μg/g, or 100–300 μg/g), and inactive (<100 μg/g) activity. FC cutoff values of 200 μg/g, 250 μg/g and 300 μg/g were denoted as FC1, FC2, and FC3, respectively.