Comparison of transformation zone sampling rates--a potentially useful indicator of smear taker performance.

Retrospective analysis of 18555 routinely collected smears from women in the age range 20-50 years reveals that there is a statistically significant relationship between the overall transformation zone sampling rate achieved in general practice and the detection rates for cervical abnormality. Similar analysis comparing unsatisfactory smear rates with rates for the detection of abnormality demonstrates a negative correlation which fails to achieve statistical significance. Comparison of transformation zone sampling rates achieved by smear takers sending samples to the same laboratory is proposed as a potentially useful performance indicator for smear takers.