Internal quality assurance in cervical cytology one laboratory's experience.

The results of an internal quality assurance exercise in one cervical cytology laboratory in England are presented, using different types of partial percentage re-screening of cervical smears. An overall false negative dyskaryotic rate of up to 4.3% was demonstrated, with the final cytology report diagnosis differing from the primary screening dignosis in 1.3% of cases. These finding are discussed, with the aim of helping to foster debate on the setting of national laboratory internal quality assurance standards.