At a time when the World Health Organisation (WHO) is embarking on the goal to end the global tuberculosis (TB) epidemic by implementing the End TB Strategy, the development of a new, inexpensive and quick test has come as a big boost to the mission.
The new Khatri blood test could radically alter the way medical professionals test for tuberculosis in the nations of the developing world, as revealed by James Maynard in the Tech Times on Saturday. This simple blood test could also serve to identify which patients have active infections, and serve in treatment of the disease.
As pointed out by Purvesh Khatri of the Stanford University School of Medicine, one-third of the world’s population is currently infected with TB. Even if only 10% of them get active TB, that’s still 3% of the world’s population - 240 million people.
TB is an infectious bacterial disease caused by Mycobacterium tuberculosis, which most commonly affects the lungs. It is transmitted from person to person via droplets from the throat and lungs of people with the active respiratory disease.
In healthy people, infection with Mycobacterium tuberculosis often causes no symptoms, since the person’s immune system acts to “wall off” the bacteria. The symptoms of active TB of the lung are coughing, sometimes with sputum or blood, chest pains, weakness, weight loss, fever and night sweats. Tuberculosis is treatable with a six-month course of antibiotics.
In 2014, 9.6mn  people fell ill with TB and 1.5mn  died from the disease, according to the WHO. Over 95% of TB deaths occur in low- and middle-income countries, and it is among the top five causes of death for women aged 15 to 44. In 2014, an estimated 1 million children became ill with TB and 140,000 children died of TB, which is also a leading killer of HIV-positive people: in 2015, 1 in 3HIV deaths was due to TB.
Globally in 2014, an estimated 480,000 people developed multidrug-resistant TB. The Millennium Development Goal target of halting and reversing the TB epidemic by 2015 has been met globally. TB incidence has fallen by an average of 1.5% per year since 2000 and is now 18% lower than the level of 2000.
Previous tests for TB involved examining the sputum, heavy respiratory secretions of potentially-infected patients. One of the problems with this testing method is that it becomes increasingly difficult for doctors to obtain samples as patients recover and mucus is reduced.
The new diagnostic method is 86% effective in children, and does not produce false positives among those who have been immunised against the disease, or those with an inactive infection.
Given that the new test is designed to be quick and inexpensive, healthcare centres in the developing world should have the facilities to easily diagnose and treat local populations, as Maynard suggested.