Table 14

‘PAID’ scheme for summarising IBD biopsy histology

PatternRecorded as text; no code
Grade (at each site)Criteria*Code
 NoneNo intraepithelial neutrophils, erosions, or ulcersA0
 MildCryptitis in up to 25% of crypts/crypt abscesses in up to 10% of crypts/bothA1
 ModerateCryptitis in >25% of crypts/crypt abscesses in >10% of crypts/sparse small foci of surface erosion/combinationsA2
 SevereUlceration or multiple foci of erosionA3
 IBD definite/very likelyHistology is of IBD, or is highly suggestive/supportive of IBD. Subcategorise as belowIBD-DVL
 IBD favoured over other causesHistology is more likely to be IBD than other causes, but is not convincing. Subcategorisation may be inappropriateIBD-F
 No evidence of IBDIBD-0
Subcategory of IBD†
 UC definite/very likelyHistology is of UC, or strongly favours UC over CDUC-DVL
 UC favoured over CDHistology does not distinguish, but favours UC over CDUC-F
 IBD unclassifiedNeither UC nor CD is favouredIBDU
 CD favoured over UCHistology does not distinguish, but favours CD over UCCD-F
 CD definite/very likelyHistology is of CD, or strongly favours CD over UCCD-DVL
 No dysplasiaD0
 Low-grade dysplasiaSpecify site(s), and number of biopsies involvedDL
 High-grade dysplasiaSpecify site(s), and number of biopsies involvedDH
 Indefinite for dysplasiaUnclassifiable atypiaDI
  • *Modified from previous schemes.3 ,12 ,40 ,52 ,53

  • †In conjunction with the clinical picture.

  • CD, Crohn's disease; DH, dysplasia, high grade; DL, dysplasia, low grade; DVL, definite or very likely; F, favoured; IBD, inflammatory bowel disease; IBDU, inflammatory bowel disease, unclassified; UC, ulcerative colitis.