Quality assurance in cervical cancer screening: results of a proficiency testing scheme for cytology laboratories in the north west Thames region

To examine the effectiveness of introducing External Quality Assessment (EQA) into all laboratories which undertake gynaecological cytopathology. To assess pathologists and cytotechnologists regularly for their competence to screen cervical smears, regardless of their standing in the laboratory hierarchy or their experience of gynaecological cytopathology. Each participant was asked to screen and report on 10 slides during a 2 h period. The assessment was carried out by a facilitator under the direction of a specially appointed EQA Committee. A maximum score of 20 points was awarded for a completely correct set of answers. A minus score was awarded for a missed abnormal smear. Seventeen pathology laboratories in North West Thames Regional Health Authority participated; 146 cytologists were assessed. A pilot and four rounds of EQA have been completed and a total 5350 smears examined. Out of 2568 dyskaryotic (abnormal) smears screened, 0.7% were not identified correctly. Of the 146 cytologists taking part in the assessment, 95% achieved a score of 17 or more. Three participants were identified who did not reach an acceptable level of competence and appropriate remedial action was taken. The EQA scheme detected unacceptable levels of performance which can be quickly rectified. Participation of 100% has been maintained on a voluntary basis, and 4 years experience of the scheme confirms that a very high standard of screening prevails in the Region. The study illustrates that voluntary self-regulation is acceptable in the NHS, and the introduction of similar EQA schemes on a national scale will go a long way to establishing confidence in the cervical cancer screening programme.