QUALITY-CONTROL STUDY ON NEGATIVE GYNECOLOGICAL CYTOLOGY IN MEXICO

An external evaluation of the quality of diagnosis of gynecological cy tology specimens (Papanicolaou or ''Pap'' tests) in the Cytopathologic al Laboratory at the Mexico General Hospital was performed, with evalu ation of 6,011 Pap tests randomly selected from 31,378 Pap studies pre viously reported as negative during 1988-1989. These tests were part o f the early detection program for cervical cancer run by the Ministry of Health of Mexico City. A quality index for specimens was constructe d based on the presence of endocervical cells, mucus, and squamous met aplastic cells. The index of false negatives for the diagnosis of cerv ical neoplasm in this sample which correspond to diagnostic error by t he examiner was 0.18% (11). The constructed quality index revealed tha t 64.1% of specimens were low quality. The correlation between diagnos tic error and low quality was .87 Results indicate that laboratories p articipating in early detection programs for cervical cancer in develo ping countries need to implement (1) external evaluation programs for Pap diagnosis; (2) permanent training programs in registration; and (3 ) monitoring procedures for collection, fixation, and transportation o f cytologic materials.