COLLECTION OF FAECAL SAMPLES

Sampling of faecal calprotectin; general advice

In proctitis the area of inflamed mucosa is very limited and the contact time between stool and tissue may be short, especially if the sample is collected late in the day and not from the first defecation. In this situation the intestinal content may pass the short inflamed area very rapidly, not allowing “the incubation time” in the gut to be sufficient for delivery of calprotectin into the stool. This is the reason why it is recommended that samples for calprotectin determination should be collected from the first defecation in the morning, thereby ensuring that “the incubation time” is sufficient. Lasson et al.  studied fecal calprotectin in patients with active ulcerative colitis, samples were collected from consecutive defecations during the day. They found that the levels are highest in samples collected when there is long time between the defecations. It is concluded that the sampling should be the same from day to day, preferably in the morning.