The future looks bright: low-cost fluorescent microscopes for detection of Mycobacterium tuberculosis and Coccidiae

In many resource-poor countries, diagnosis of tuberculosis is based on microscopy of Ziehl-Neelsen-stained smears. However, the fluorescent stain auramine performs better and allows the detection of more positive smears. The limitation for its widespread use has been the high cost for fluorescent microscopes, especially the frequent replacement of the expensive light source, which lasts only 200-300 h. Novel light-emitting diodes (LED) are alternatives and last ten thousands of hours. Based on LEDs, rather inexpensive solutions for fluorescent microscopes are now available and thus auramine may be a cost-effective step to improve the diagnosis of tuberculosis in resource-poor countries.