Within the strategies of internal quality control, the review of previous negative Papanicolaou smears from patients with diagnosis of CIN 2 or CIN 3 is considered one of the most efficient for detection of false negative results. In the present study we reviewed the previous negative smears of cases with diagnosis of CIN 2 or CIN 3 during the years of 1998 and 1999. During this period the Adolfo Lutz Institute has performed 113.619 Papanicolaou tests; 233 cases were diagnosed as CIN 2 or CIN 3. The cases diagnosed as unsatisfactory were excluded. Among the 36 cases from which there were previous smears in the period of 36 months before the original diagnosis, we found 22 cases of CIN (12 CIN 1, seven CIN 2 and three CIN 3) and 14 cases diagnosed as inflammatory or normal. When those 14 smears were reviewed, the following diagnosis were found: unsatisfactory (two cases), inflammatory (five cases), Ascus (three cases), CIN 1 (three cases), CIN 2 (one case). In conclusion, the review of previous negative Papanicolaou smears is a highly efficient strategy in order to detect false negative results. This practice can be useful as a guide for continued education measures.
High grade squamous lesion; Intraepithelial cervical; neoplasia; Quality control of cytopathology; Cervical smears
