The CyScope® fluorescence microscope, a reliable tool for tuberculosis diagnosis in resource-limited settings

Poor laboratory equipment and few human resources have made it difficult to implement microscopic diagnosis of pulmonary tuberculosis (TB) on a large scale basis worldwide. Three hundred sputum samples from patients in Cameroon were studied by using the CyScope®, a new light-emitting, diode-based, fluorescence microscope, to compare auramine-rhodamine fluorescence with the conventional Ziehl-Neelsen staining method. Five fluorescence protocols were tested to reduce manipulation time. Smear positivity for acid-fast bacilli with the Ziehl-Neelsen staining method was 27.7% (83 of 300) compared with 33.3% (100 of 300) with the fluorescent method. Staining time with the modified fluorescence protocol could be reduced from 21 minutes to 10 minutes. This study confirmed that the fluorescence staining method is more sensitive than the Ziehl-Neelsen staining method. It is suggested that the training of laboratory technicians on fluorescence microscopy should be scaled up for increased disease control.