Select the histological grade from the pathology report to visualize the mucosal healing status.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Standardized histological assessment of mucosal healing in Ulcerative Colitis (UC)
To define the target of "Histological Remission" (NHI ≤ 1)
Research-grade evaluation of biopsy specimens following therapeutic induction
Predicting the risk of future clinical relapse even in patients with endoscopic remission
Histological vs. Endoscopic Healing
Clinical guidelines (STRIDE-II) now recognize histological remission as a "secondary" target. Achieving histological remission (Grade 0 or 1) is associated with superior outcomes compared to achieving only endoscopic remission (Mayo 0).
Section 2
Formula & Logic
The 5 Grade Scale (0–4)
01
Grade 0: No significant inflammation.
02
Grade 1: Chronic inflammatory infiltrate (plasma cells/lymphocytes) but no neutrophils.
03
Grade 2: Mild active inflammation (neutralphilic infiltrate in the lamina propria).
04
Grade 3: Moderate-to-severe active inflammation (neutrophils in the crypts).
05
Grade 4: Ulceration (Presence of superficial fibrin/granulation tissue).
Diagnostic Thresholds
Grade 0 or 1
Histological Remission
Grade ≥ 2
Active Histological Disease
Section 3
Pearls/Pitfalls
Nancy vs. Robarts vs. Geboes
The Nancy Index is significantly simpler and easier to implement in clinical practice than the complex Geboes score. It has extremely high inter-observer reliability, making it the preferred choice for many recent clinical trials of JAK inhibitors and S1P modulators.
The Neutrophil Rule
The Presence of even a single neutrophil (Grade 2+) precludes the diagnosis of histological remission. Neutrophils are the "active" marker of imminent mucosal injury.
Clinical Pearls
NHI Grade 4 (Ulceration) is the histological correlate of the endoscopic Mayo Grade 3
Patients in histological remission have a 2-3x lower risk of hospitalization over 3 years compared to those with "Endoscopic-only" remission
Nancy score was the first to be validated specifically for reproducibility between expert and general pathologists
Section 4
Next Steps
Clinical Triage
01
NHI ≥ 2: Active inflammation. Consider dose-optimization if symptoms or biomarkers (calprotectin) are also elevated.
02
NHI ≤ 1: Success. Deep mucosal healing achieved.
Complementary Scoring
Mayo Endoscopic Subscore (MES)
Robarts Histopathology Index (RHI)
Geboes Score (Detailed Histology)
Section 5
Evidence Appraisal
The Defining Paper
Development and validation of the Nancy histological index for UC.
Marchal-Bressenot A et al. • Gut. 2017;66(1):43-49. The development and rigorous validation study.
Developed by the IBD research group in Nancy, France (led by Professor Laurent Peyrin-Biroulet). It was specifically designed to be the UC equivalent of the "Simple Endoscopic Score," prioritizing accuracy and ease of use over morphological minutiae.
