fibrosgradering

Fibrosgradering, or fibrosis grading, is the process of evaluating and staging the amount and distribution of fibrous tissue in a biopsy or tissue sample. The degree of fibrosis reflects chronic injury and scarring and is used to assess disease severity, prognosis and response to therapy. Grading is typically performed by a pathologist using histological stains that highlight collagen, and is often complemented by assessment of inflammation and architectural distortion.

In liver disease, several semi-quantitative scoring systems are commonly used. METAVIR staging ranges from F0 (no fibrosis) to F4 (cirrhosis); Ishak scores range 0–6; Batts-Ludwig uses 0–4. Similar organ-specific schemes exist for other tissues; for example, the Banff classification for kidney allograft biopsies includes scoring of interstitial fibrosis and tubular atrophy. The choice of system depends on the organ and the clinical question.

Methodology typically involves staining formalin-fixed, paraffin-embedded tissue sections with dyes such as Masson's trichrome or Sirius red to visualize collagen. Scoring may be semi-quantitative, based on the percentage of field fibrosis or particular patterns, or quantitative, using digital image analysis to estimate fibrotic area.

Clinical use and interpretation: fibrosis stage informs prognosis, helps guide treatment decisions, and serves as an endpoint in clinical trials. In practice, biopsy results are integrated with clinical data and non-invasive tests, such as elastography and serum fibrosis markers, to determine disease status and monitor progression.

Limitations include sampling error due to focal fibrosis, inter- and intra-observer variability, and the lack of universal standardization across organs and scoring schemes. Ongoing research aims to standardize terminology and improve reproducibility through digital pathology and automated scoring.