A new $240 microscope that runs on AA batteries is as effective for diagnosing tuberculosis as $40,000 professional laboratory models.
The microscope, described online in the journal PLoS ONE, weighs just two and a half pounds and could be used in developing countries that lack expensive lab equipment and reliable electricity.
"The World Health Organization estimates that 1.3 million people died from tuberculosis in 2008," study researcher Rebecca Richards-Kortum, a professor of bioengineering at Rice University, said in a statement. "[The microscope], which is portable, durable and inexpensive, could be used to diagnose tuberculosis in community or rural health centers with limited infrastructure in the developing world, promoting early detection and successful treatment of the disease."
The microscope was developed by Andrew Miller, then a Rice undergraduate and now a designer for San Francisco-based medical device firm Thoratec. To test the microscope's reliability, Miller and his colleagues used 64 slides of saliva samples, some of which were contaminated with tuberculosis. Each sample was stained and examined under Miller's portable Global Focus microscope and under a standard laboratory microscope worth thousands of dollars. The person examining the slides did not know which were contaminated. In 98.4 percent of cases, the examiner's conclusions using both microscopes were identical.
The researchers have filed a patent on the microscope and have contracted with the medical device company 3rd Stone Design to produce 20 models that will be field tested next month, according to Rice University.
"This is hugely significant as a point-of-care tool clinicians can use for tuberculosis patients, whether they're in Asia or Africa or even in West Texas," study co-author Edward Graviss of the Methodist Hospital Research Institute in Houston said in the statement. "The first identification of TB is usually made with a smear, and it will be good to know that in the field instead of having to wait three or four days to get the smear to a lab."