Of the referred children with functional abdominal pain, 87% met the PRC-III for specific diagnoses. This supports the use of these criteria as a diagnostic tool. The significant overlap between different FGIDs, however, makes it unclear whether some of the diagnoses represent distinct disorders or artificial categories.

The faecal calprotectin concentration is within normal limits in FGID and does not vary with different FGID entities suggesting that bowel inflammation is not a significant part of the pathogenesis in FGID.