Table 2.

Modified scoring system for histological assessment of ulcerative colitis

Inflammation grade	Score	Intensity	Histological criteria
Active inflammation	0	Normal	Neutrophils not present in crypt or surface epithelium and no exudate, erosion or ulceration
	1	Low grade	Neutrophils present transmigrating through the crypt epithelium or within crypt lumina in < 20% of crypts; no erosions or ulcers
	2	Moderate	Neutrophilic infiltration in > 20% of crypts or presence of erosions
	3	High grade	Presence of ulcers
Chronic inflammation	0	No increase	Normal number of chronic inflammatory cells present primarily in the superficial lamina propria
	1	Moderate	Moderate number of mononuclear cells
			Aggregated between crypts at the base of the lamina propria
	2	Severe	Marked increase in chronic inflammation shown by sheets of chronic cells
Crypt distortion	0	None	Crypts had normal outlines with only artifactual irregularities
	1	Mild	Scattered or rare crypts showing irregular (bent, forked) outline
	2	Moderate	Approximately 25%-50% of crypts with an irregular outline
	3	Severe	> 50% of crypts with an irregular outline

Adapted from Hanauer et al[50], 1998.