Quality Control in Cervical Cytopathology: a Leterature Review

Abstract

Cervical cytopathology is an important tool for the detection of precursor lesions of cervical cancer, which are still treatable at that stage, thus resulting in a significant decrease in mortality. However, cervical cytopathology has drawbacks, with the false-negative rate varying from 2 to 50%. False-negative results are mainly due to errors in sample collection, examination, and interpretation. The ultimate objective of routine internal and external quality control in laboratories is to improve the test's diagnostic performance, evaluate screener performance, and identify causes of sample collection errors. Internal quality control can be performed regularly and involves monitoring the sample adequacy, duration of the examination, screener workload, hierarchical review of smears, and review of negative smears. Internal quality control can also include analysis of the cytology/histology correlation, review of previous exams, monitoring of statistics on frequency of lesions and sample adequacy, and deliberate inclusion of abnormal smears in routine exams. Continuing education, personnel training, and periodic proficiency exams are strategies that should be adopted. Random or 100% review of smears, rapid review, and detailed reviews are methods that have advantages and disadvantages for the detection of false-negative results. It is the laboratory's task to define the best strategy for internal quality control that will lead to improvement in technical procedures and consequently in the quality of the service provided by cytopathology laboratories.