This term distinguishes the more minor, low grade lesions (with minimal danger), from the more serious, high grade lesions (with greater danger).

Low grade lesions (LSIL) include mild dysplasia, HPV changes, and CIN 1.

High grade lesions (HSIL) include moderate dysplasia, severe dysplasia, carcinoma in situ, CIN 2, and CIN 3. In essence, everything that is worse than mild dysplasia, but not as bad as invasive cancer of the cervix.