Usefulness of the paralens fluorescent microscope adaptor for the identification of mycobacteria in both field and laboratory settings.

Abstract

The presence of acid-fast bacilli (AFB) in laboratories has traditionally been demonstrated using the fluorochrome method, which requires a fluorescent microscope or the Ziehl-Neelsen (ZN) method employing light microscopy. Low sensitivity of the ZN method and high costs of fluoroscopy make the need for a more effective means of diagnosis a top priority, especially in developing countries where the burden of tuberculosis is high. The QBC ParaLens attachment (QBC Diagnostic Inc., Port Matilda, PA) is a substitute for conventional fluoroscopy in the identification of AFB. To evaluate the efficacy of the ParaLens LED (light-emitting diode) system, the authors performed a two-part study, looking at usefulness, functionality and durability in urban/rural health clinics around the world, as well as in a controlled state public health laboratory setting. In the field, the ParaLens was durable and functioned well with various power sources and lighting conditions. Results from the state laboratory indicated agreement between standard fluorescent microscopy and fluorescent microscopy using the ParaLens. This adaptor is a welcome addition to laboratories in resource-limited settings as a useful alternative to conventional fluoroscopy for detection of mycobacterial species.