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.
Citation
Masters of Medicine (Clinical Cytology)Publisher
University of Nairobi School of Medicine