When an unsatisfactory smear (thick inflammatory infiltrate or blood i
nfluencing the staining characteristics of the epithelial cells) is re
stained for MiB-1, the diagnostic proliferating cells are visualized,
and the MiB-1-positive smears can be thus upgraded as borderline, grad
e I, II, and III, corresponding with the cytologic diagnoses of, respe
ctively, ASCUS, CIN I, II, and greater than or equal to III. In a peri
od of 18 months, 2,068 unsatisfactory smears out of a material of 84,8
17 smears were restained for MiB-1. In the unsatisfactory group, signi
ficantly more abnormal smears were detected than in the satisfactory g
roup. Seventy-five of the unsatisfactory group were biopsied because o
f the MiB-1 findings: Three women proved to have severe dysplasia, fou
r had carcinoma in situ, and three had invasive carcinoma. The permill
age for invasive cervical carcinoma was ten times larger in the unsati
sfactory group than in the satisfactory group; thus the MiB-1 method h
as further enhanced our diagnostic acumen in this difficult type of sm
ears. (C) 1996 Wiley-Liss, Inc.