Comparison of cervical cytology reporting rates: a useful adjunct to external quality assurance

Reporting rates for abnormal and inadequate cervical smears have been compared during a 5-year period in nine laboratories and related to targets and achievable ranges recently recommended by the National Health Service Cervical Screening Programme (NHSCSP). There was improved consistency in rates for all grades of abnormality as well as inadequate smears. The average rate for moderate and severe dyskaryosis combined increased to 1.6%, which is the target recommended by the NHSCSP, and the standard deviation fell from 0.52 to 0.27. Although average rates for mild dyskaryosis and borderline nuclear change combined and inadequate smears both remained within the achievable range recommended by the NHSCSP, four laboratories were above the upper limit for each of those categories in the final year. During the 5 years of the study there was a fall in the number of 'inflammatory' smears coded as negative with a recommendation for early repeat. Only one laboratory still uses that category. The challenge for the future lies in controlling high rates for minor abnormalities and inadequate smears while maintaining acceptable rates for moderate and severe dyskaryosis. Comparison of reporting rates is regarded by the participating laboratories as a useful adjunct to external quality assurance.