'Electronic nose' to detect TB
[DHAKA] Scientists from Bangladesh and the Netherlands have proven the efficiency of an electronic diagnostic device that detects tuberculosis (TB) of the lung.
The device, named electronic nose (eNose), can obviate cumbersome conventional diagnosis where patients' sputum is examined under the microscope, cultured in a laboratory and lung X-rays taken to confirm infection.
Pilot studies, done in collaboration with Bangladesh's National TB Control Programme and lasting seven months until September 2009, proved the new device to be simple, rapid, highly sensitive and specific. The findings have been reported ithis month (05 Nov) in Tuberculosis Journal.
About 230 subjects, both healthy and active TB germ carriers, were involved in the studies.
"This is a revolutionary invention which will give significant advantage to users in places with a high TB infection burden like Bangladesh," said Zeaur Rahim, a scientist who led the studies at the International Centre for Diarrhoeal Disease Research, Bangladesh.
"Since there is no direct handling of patients' biological samples, the device allows risk-free diagnosis," Rahim told SciDev.Net
The device scores on accuracy and early diagnosis which are essential to controlling pulmonary TB in countries with high TB prevalence. Sputum cultures take weeks or months to develop results and microscopy cannot predict viability or resistance patterns.
According to a WHO report there were 8.8 million new cases and 1.5 million associated deaths in 2010 with a new TB infection occurring every second.
Patients are required to exhale into an airbag which is then passed over metal oxide sensors within the device that detect volatile organic compounds produced by Mycobacterium tuberculosis – the organism that causes TB.
Data from the sensors are analysed with the aid of computers and compared against preset values for normal air. The device is capable of rapidly identifying several bacterial species, other than M. tuberculosis.
A commercial version of the tool, called DiagNose, will reduce the cost of each TB test to less than US$10, which is far cheaper than conventional diagnostic methods, Marcel Bruins, a Dutch researcher with the eNose company and associated with the project, told SciDev.Net.
"Our aim is to develop a low-cost, user-friendly TB-screening device that can be used globally. If it turns out, for instance, that TB in Bangladesh differs from TB in Africa, this can be resolved by adjusting the software," Bruins said.