TB testing revolution

A test that can detect TB, including drug-resistant forms, in less than two hours could revolutionise treatment of the disease, according to the World Health Organisation (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.

Some patients have to wait as long as three months to be diagnosed, which means their treatment is delayed and their prospects of recovery are reduced.

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. Dr Mario Raviglione, director of the WHO’s Stop TB department, said: “This new test represents a milestone for global TB diagnosis and care.”

He said: “We have the scientific evidence, we have defined the policy, and now we aim to support implementation for impact in countries.”

Trials and demonstration studies have been carried out over 18 months in a number of countries, involving more than 8 000 patients. 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 conventional laboratories - although the need for a constant electricity supply may be a problem in rural settings.

The major issue now will be cost. The market price for the equipment is $55 000 to $62 000, with an additional $55 to $82 for the cartridges it uses.

The makers, Cepheid, have agreed to cut the price by 75% for the poorest countries. But at $16,86 a test, the cost is higher than the current system and the roll-out will depend on donor funding.—Guardian News & Media 2010