Results of a control quality strategy in cervical cytology
To determine the efficacy of a quality control strategy in cervical cytology in the detection of high-grade squamous intraepithelial lesions.
Forty-two patients were selected who underwent a Pap smear and cervical uterine biopsy between April 2008 and December 2009, with evidence of a high-grade squamous intraepithelial lesion in one or both tests. The statistical parameters of the smear test were calculated before and after systematic meetings for review of the archived test results (6 years), in which the following was done: interobserver diagnostic consensus; cytohistological correlation, with the latter as gold standard; and evaluation of the therapeutic status of each patient.
Once these controls were applied, it was noted that sensitivity and positive likelihood ratio of the test for high-grade squamous intraepithelial lesion increased 9.5% (34.5 to 44%) and 0.45% (1.64 to 2.09%), respectively, while specificity remained at 79%. Reduction in interference of false-negative results associated with errors in the analytical phase of the cytological productive process gave an estimate of failures in collection of the specimens (pre-analytical phase).
In addition to improving the performance of the cytological diagnosis of the high-grade squamous intraepithelial lesion, the proposed quality control strategy allows a reflection on the causes of incorrect or conflicting scrutiny.