Medics have often relied on microscopes and chest x-rays to diagnose TB in patients, which lasts for weeks to see results. But a new technology set to be available in South African Clinics soon, only takes about 90 to 105 minutes to diagnose the disease, that could lead to earlier diagnosis and treatment to prevent deaths.
Termed as the rapid “GeneXpert tuberculosis test”, it was previously introduced in the country in 2011 to diagnose TB as well as other forms of drug resistant TB in a short period, showing 60 per cent higher accuracy than the conventional TB testing.
However, the revolutionary test has only been available in labs and not clinics meaning that samples sent would take a couple of days to receive results. Nevertheless, the technology set to be ready for use in clinics does not require much technical expertise to use. In a study conducted by the University of Cape Town, it was discovered that nurses instead of lab technicians were able to administer the test in clinics in Zimbabwe, Zambia, South Africa and Tanzania.
It was found that the nurses could accurately run the GeneXpert machines after a single day’s training. Moreover, the study found that using the new technology in the clinics increased the number of patients starting same day treatment by half. Yet, experts concur that only half of all patients diagnosed with multidrug-resistant TB in South Africa receive treatment. However, access to the GeneXpert would serve as a breakthrough as it can diagnose several forms of TB which are drug resistant, in turn helping the country control the rising cases of TB.
Reports say that South Africa has the highest cases of XDR drug resistant TB worldwide with only 16per cent drug resistant TB cases tested. The GenXpert TB test unlike the conventional form of testing that involves microscopes and X-rays, has its results obtained using fluorescent probes known as molecular beacons.
The test detects DNA sequences specific for Mycobacterium TB and drug resistance TB through a polymerase chain reaction and is based on a platform for rapid and simple to use nucleic acid amplification tests (NAAT). The system then purifies concentrates of TB pathogens from samples, isolating genomic material from the sampled bacteria by sonication and then amplifies the genomic DNA through Polymerase chain reaction.
The process identifies drug resistant TB mutations in the TB genome in a format using fluorescent probes. However, although the test can be performed in a doctors office if necessary, the challenge lies in the cost of the technology that diagnoses TB in less than two hours. The agreed price for a GeneXpert system is currently $17,000USD for a four module instrument, reports say.