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