Specimens may be unsatisfactory due to obscuring blood, overly thick smears, air-drying of alcohol-fixed smears or an inadequate number of follicular cells.
Specimens containing at least five groups of follicular cells, each composed of at least ten cells, are considered satisfactory for evaluation.
With experience, the average unsatisfactory rate is about 5% to 10%. It is incorrect to consider unsatisfactory or non diagnostic tests as negative. The lowest unsatisfactory rate will be achieved by close cooperation between the clinician and the cytopathologist, with immediate assessment of material.