RESUMEN
SETTING: A non-governmental organisation (NGO) supported tuberculosis control programme in Bangladesh with good smear microscopy. OBJECTIVE: To verify whether bleach sedimentation method increases the sensitivity of sputum smear microscopy for acid-fast bacilli (AFB), and if so, how. DESIGN: Duplicate smears from successive routine specimens, peripheral centres examining direct smears, and blind examination of bleach sediment smears at central laboratories. RESULTS: When all 3,287 sputum samples were examined in duplicate and the International Union Against Tuberculosis and Lung Disease cut-off for positivity was applied, more positives were not found by bleach sedimentation. Using the much lower American Thoracic Society (ATS) threshold, the percentage positives rose slightly from 15.5% for direct smear to 16.6% after bleach. The gain was more evident when suspect examinations only were taken into consideration, as bleach missed many positives identified by direct follow-up smear. When patients rather than individual smears were counted, more suspects were detected by bleach (10% gain on average), but with considerable variation between the centres (range 6-16%). To arrive at this gain, the ATS cut-off was used, with corrections for false results. Under routine conditions, however, this threshold is too low in view of possible transfer of AFB. CONCLUSIONS: Bleach sedimentation can increase the diagnostic yield, but only to a minor extent if all other factors have been optimised already; it is not a panacea. Precautions against false negatives as well as false positives should be taken, and the additional workload is not negligible.
Asunto(s)
Técnicas Bacteriológicas , Mycobacterium tuberculosis , Hipoclorito de Sodio , Manejo de Especímenes/métodos , Esputo/microbiología , Tuberculosis Pulmonar/diagnóstico , Tuberculosis Pulmonar/microbiología , Bangladesh , Sesgo , Recuento de Colonia Microbiana , Reacciones Falso Negativas , Reacciones Falso Positivas , Humanos , Microscopía , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
A 14 year old boy is presented who was admitted to the psychiatric ward because of delirium. He also had gynaecomastia, facial oedema, striae, and hypertension. He was finally proved to have a mixed oestrogen and cortisol producing adrenal tumour which was removed surgically with complete improvement and no relapse.
