A staggering 10.4 million individuals were diagnosed with tuberculosis (TB) in 2015, and 1.8 million died from the disease. In addition, a total of 480,000 cases of multidrug-resistant TB were also reported that same year. TB continues to be a major public health threat, despite the fact that it is a curable disease. Therefore, when it comes to TB, drug-resistant or not, a rapid and accurate diagnosis is imperative.
All strains of TB are spread through the air, with bacteria passed on from one individual to another. When it comes to diagnosis of the disease, as with most infection, an early diagnosis is best so that the infected individual can receive treatment as quickly as possible to effectively control the disease. New diagnostics in the field are slowly changing the landscape as we know it, and now, a team of researchers have conducted a trial dedicated to studying the effectiveness of a molecular diagnostic test performed in the clinic compared with the test completed in a laboratory. The researchers hypothesized that this point-of-care test would result in better patient outcomes.
For the study, the researchers conducted a randomized controlled trial
of the test in a rural clinic in South Africa, northern KwaZulu-Natal, a region with the highest rates of HIV and HIV-associated TB in the world. The study participants were randomized into 2 groups: point-of-care, which consisted of 651 patients, or laboratory testing, which consisted of 646 patients. All participants were adults reporting cough, and were either HIV-positive or at increased risk of drug-resistant TB.
Study leader Richard Lessells, PhD, a former clinical research fellow at Africa Health Research Institute (AHRI), and his team compared 2 testing systems: one where a nurse performed Xpert MTB/RIF at a rural South African clinic, and one where researchers transported sputum samples to a central laboratory where technicians performed Xpert MTB/RIF.
“To fight TB in South Africa and elsewhere, we need to decentralize both diagnosis and treatments in a coordinated manner,” Dr. Lessells explained. “Nurses are at the frontline of TB and HIV care in South Africa, and we need to give them the tools to make the correct diagnosis and initiate the correct TB treatment in a single encounter.”
According to the study results, the researchers found that performing a molecular diagnostic test during a patient’s visit at a clinic “greatly reduced the time to treatment for patients who did not have a drug-resistant form of the disease,” compared with performing the test at a centralized laboratory, according to a recent press release
They found that the testing delivery system involving nurses at the clinic provided patients with a diagnosis within hours of their visit, and 3 out of 4 patients (who did not have drug-resistant TB) were able to begin treatment that same day.
In contrast, patients had to wait, on average, 7 days to begin treatment with the diagnostic testing performed by the laboratory. Furthermore, they found that beginning treatment within 30 days after receiving diagnosis “was better with point-of-care than laboratory diagnosis.” However, the difference was “not statistically significant.”
“Research has shown that in South Africa and other countries with high TB burden, up to 1 in 4 people with a laboratory diagnosis of TB do not start TB treatment,” explained Dr. Lessells in the press release. “Theoretically, we now have the technology to diagnose TB and initiate treatment during a single visit—something that happens routinely with HIV and malaria—but we wanted to test this technology in the real world to see if it could actually deliver this.”
The point-of-care diagnosis did not reduce time to treatment for patients who had drug-resistant TB. According to the press release, this may be because at the time of the study, a local treatment program for drug-resistant TB had yet to be created; however, such a program now exists, and time to treatment has thus been shortened.
“The holy grail of TB remains to be developed: a simple, rapid rest that does not rely on sputum, that can be performed in a few minutes by a nurse or community health worker and that detects all forms of TB,” Dr. Lessells concluded.
Until researchers develop the “holy grail” test, point-of-care diagnosis may link countless infected individuals with needed treatment more rapidly, which can help these individuals prevent their infection from becoming more severe, and even deadly.
The Xpert MTB/RIF test is relatively new—less than a decade old—but “highly accurate” when it comes to the identification of TB bacteria, and it only takes 2 hours to yield results. The test is also capable of identifying resistance to first-line TB drug rifampicin.
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