Issues affecting adequacy:
(1) whether the disorder is focal or diffuse
(2) the severity of the disorder
The diameter of the needle biopsy may vary depending on the size of the needle. Most biopsy needles give cores that have a diameter from 1.4 to 2.1 mm.
Criteria for adequacy:
(1) length: for grading fibrosis in chronic hepatitis the minimum length is 2 cm and 3 cm is preferred
(2) number of portal tracts (there should be about 6 portal tracts per cm of a core biopsy)
If the core is too short or if there are not enough portal tracts then the interpretation may underestimate the severity of the disorder.
Additional factors affecting the biopsy:
(1) subcapsular fibrosis
(2) angle of needle entry (which can increase the amount of fibrosis)
(3) fragmentation of the specimen as in cirrhosis
(4) artifacts from crushing, cautery, etc.
