A test that can detect TB, including drug-resistant forms, in less than two hours could revolutionize treatment of the disease, according to the WHO, which is urging its roll-out across the globe.
Tuberculosis killed 4,700 people every day last year. The annual death toll of 1.7 million includes 380,000 people who are at particular risk because they have HIV.
The current diagnostic test for TB has been used for 125 years. It involves microscopic examination of a sputum sample and is not ideal because it doesn’t easily detect the growing number of strains that are resistant to antibiotics, or TB where the patient is also infected with HIV.
Some patients have to wait as long as three months to be diagnosed. The long wait also increases the chances they will infect others and, if they are given the wrong antibiotics for their particular strain of TB, drug resistance can worsen.
The new test delivers a result in 100 minutes.
“This new test represents a milestone for global TB diagnosis and care. It also represents new hope for the millions of people who are at the highest risk of TB and drug-resistant disease,” said Mario Raviglione, director of the WHO’s Stop TB department. “We have the scientific evidence, we have defined the policy, and now we aim to support implementation for impact in countries.”
The test is a fully automated nucleic acid amplification test, which the WHO says is simple and safe to use. It incorporates modern DNA technology that can be used outside of conventional laboratories — although there is need for a steady electricity supply.
The market price for the equipment is US$55,000 to US$62,000, with an additional US$55 to US$82 for the cartridges it uses. The makers, Cepheid, have agreed to cut the price by 75 percent for the poorest countries. However, at US$16.86 per test, the cost is higher than the current system.