Interobserver variation in the assessment of the sampling quality of cervical smears

In order to assess the interobserver variation among cytological assistants in evaluating the sampling quality of cervical smears, all four laboratory assistants from one cytological department examined the same set of 71 smears. They assessed the presence of endocervical cells, the quality of fixation, the number of cells and the undesirable presence of clumps of cells. The interobserver agreement, uncorrected for chance, varied from 73 to 93% for the presence of endocervical cells and from 86 to 100% for the three other criteria. For the presence of endocervical cells, the kappa values, a measure for the interobserver agreement corrected for chance, varied from 42 to 84%. This is a reasonable outcome. For the three other criteria many kappa values were zero or uncalculable. The interobserver agreement in evaluating the sampling quality of cervical smears is reasonable to good, but not perfect. Prudence in the interpretation of quality data is warranted.