Sputum cytology: a limited role

To determine the cost and sensitivity of sputum cytology in routine use and to determine when sputum cytology is most appropriate.

A retrospective study, based on all sputum cytology requests received in five histopathology/cytopathology laboratories in Yorkshire from 1 January to 31 December 1993. Cytology findings were correlated with histological diagnosis or clinical outcome, and related to the speciality of the referring clinician.

Laboratory practice and performance was similar in all five centres. The average laboratory cost of sputum cytology was 26.93. The mean absolute sensitivity was 36% and the specificity was 99.6%. The majority of specimens was submitted by general physicians or geriatricians. The largest proportion of positive specimens were submitted by chest physicians.

Often sputum cytology is used inappropriately as a screening investigation on, or soon after, admission. In addition, it is used inappropriately before bronchoscopy. Sputum cytology should be limited to individuals in whom a histological diagnosis is desired, but in whom bronchoscopy is inappropriate or unsuccessful.