[Causes and frequency of unsatisfactory cervicovaginal smears]

Inadequate Pap smear by definition is a specimen in which detection of cervical epithelial abnormality is impossible or uncertain. This causes poorer detection of intraepithelial lesions of a mild and more severe grade, including the possible false-negative diagnosis. Sample adequacy is most crucial in the evaluation of the finding, alerting the gynecologist to the limitations of the finding, its possible inaccuracy, and need to repeat the examination in order to obtain as precise results as possible. The aim of the study was to establish the frequency and reasons of unsatisfactory cervicovaginal smear samples in the course of one year, during which 1594 of 12,242 conventionally obtained cervical samples were sorted out as inadequate. These were reassessed with respect to their adequacy. Eight percent of the smears in which the evaluation of cell abnormality failed due to sample inadequacy were identified and these smears were repeated and analyzed for adequacy and presence of abnormality. The most common reasons included insufficient endocervical epithelial cells, excessive smear thickness, cells obscured with numerous inflammatory elements and erythrocytes, and sample inadequacy due to the presence of foreign material, poor fixation or staining. Inadequate equipment, insufficient material for cytologic analysis, and poor preparation technique may lead to failure to observe abnormality and errors in microscopic analysis. This implies each team member's responsibility for the accuracy of the result as well for the assurance of specimen adequacy. Reduction in the frequency of the reasons mentioned above is possible if internal control, performance quality monitoring and continuing education of each team member are conducted on a regular basis. The necessity to repeat sampling adds to the cost of health care with no considerable increase in the detection rate of epithelial abnormalities, inadequate specimens being the most common cause of false-negative cytologic findings.