Quality control in gynaecologic cytology at Ribeiro clinic in Nairobi, Kenya

Abstract

The Papanicolaou test (Pap test) remains the best method available for the detection of premalignant and malignant cervical lesions with sensitivity varying between 42-89%. Other sophisticated approaches such as the expensive automated cytologic screening or the use of Human Papilloma virus typing remain experimental and are not available in developing countries. The success of screening for cervical cancer largely depends on the technical and diagnostic competence of the personnel of a cytology laboratory. There is therefore need of an organized arrangement that has the object of ensuring that slides are ofthe required quality for proper interpretation and correct diagnosis. In this retrospective descriptive study, the aim was to determine the effectiveness of quality control in gynecologic cytology in the Project Reproductive Health (PRH Project) at Ribeiro clinic in Nairobi. It sought to determine the value ofthe following parameters of Papanicolaou test that are core to quality control and quality assurance in gynecologic cytology - Sensitivity -Specificity -Predictive value -False negative rate -Atypical Squamous Cells of Undetermined Significance (ASCUS) and - Atypical Squamous Cells of Undetermined Significance / Squamous intra-epithelial Lesion (ASCUS/ SIL) ratio. A total of 600 reports of previously diagnosed cervical/vaginal smears were used. These were randomly selected from 1000 reports of women who visited the clinic in the period between

February 1998 - July the year 2000. The attending pathologist or cytotechnologist did the reporting. A combination of cytology and histology findings was used, with histology as the "Gold Standard. The data generated was analyzed using Epi info computer program. The following results were posted: - ASCUS 12 % - ASCUSI SIL ratio 3% - Sensitivity 55-100 % - Specificity 61- 65% " - Positive predictive value 3-94% - False negative rate 9% Quality control is key to accurate diagnosis in cervical c..ancer screening using Pap smear. Because of its outstanding success in cancer prevention, expectations regarding the Pap smear's ability to detect pre-malignant lesions have now been raised too high. Unfortunately, the Pap smear is not a perfect test, and therefore, it is not possible to completely conquer cervical cancer through screening alone. However, with good quality control, screening can significantly reduce the morbidity and mortality of cancer of the cervix. From the results obtained in this study it is apparent that proper quality assurance and quality control mechanisms were in place in the PRH Programme. To further enhance quality control and possible eradication of cancer of the cervix, it is recommended that all Pap smears be screened according to a strict laboratory protocol.