A New Test Could Identify Tuberculosis in Less Than an Hour
One of the two current test options takes two visits with a health professional over 48 hours.
A new test is capable of diagnosing tuberculosis (TB) in less than an hour, according to a paper published in the medical journal Science Translational Medicine.
The paper explains how scientists identified four blood proteins that are unique to TB to develop the test.
Overall, the test was able to successfully identify TB 86% of the time, and also correctly ruled out disease in non-TB infected people 69% of the time, which are in line with the World Health Organization’s (WHO) requirements for TB testing.
Although deaths related to TB have reduced, from 1.6 million in 2017 to 1.5 million in 2018, it remains one of the top 10 causes of deaths worldwide, according to the WHO.
The scientists “used machine learning to develop an algorithm that distinguished active tuberculosis from other diseases with similar symptoms,” the paper states.
Quickly detecting the disease and distinguishing it from other respiratory infections with similar symptoms is a challenge. Typically, it has been difficult to differentiate TB symptoms from other causes of persistent cough in patients, according to the study.
The report states: “Improved tuberculosis prevention and control depend critically on the development of a simple, readily accessible rapid triage test to stratify TB risk.”
Currently, there are two different tests used to detect tuberculosis: the TB skin test and TB blood test, which both detect for TB bacteria in the body, according to the Centers for Disease Control and Prevention.
The skin test requires two visits with a health care provider. On the first visit, a small amount of fluid called tuberculin is injected on the person’s skin, at the lower part of their arm.
Within 48 to 72 hours, they visit a health professional once again, and the test results are determined by an assessment of the skin’s reaction to the injection. If there is a positive skin test, additional tests are needed to determine if it is a latent TB infection or TB disease.
A latent TB infection means TB bacteria are alive, but inactive in the body, whereas with TB disease, the bacteria are multiplying and attacking a part of the body, typically the lungs.
The TB blood test involves drawing a patient’s blood and sending it to a laboratory for analysis. If it is positive, it means that a person is infected with TB bacteria and additional testing is also required to determine if it is the latent infection or disease. This additional testing can include a chest X-ray and or testing of saliva and mucus samples.
TB is caused by bacteria that are spread through the air when a person with the disease coughs or speaks. Symptoms include a bad and persistent cough, coughing up blood or mucus, and chest pain. It is curable and preventable, but can also be deadly. The disease disproportionately impacts low-income and otherwise marginalized people, such as people with HIV, migrants, refugees, and people who are homeless.
A recent report by the WHO showed that more people with TB are receiving treatment than ever before, but an estimated 3 million people living with tuberculosis still lack access to care.