Tuberculosis (TB) is a global health challenge that affects millions of people. It is caused by the bacteria Mycobacterium tuberculosis, which mainly infects the lungs. TB can be cured with antibiotics, but it requires early diagnosis and appropriate treatment. Early diagnosis of TB and drug resistance not only helps in effective treatment but also prevents the spread of the disease. However, TB diagnosis remains a challenge in low-resource settings, where the cost and availability of diagnostic tests are often barriers to timely intervention. The solution is to invest in innovative and affordable solutions and provide effective implementation.

How TB is Diagnosed and What are the Challenges

TB is diagnosed using two tests – TB skin test (TST) and TB blood test. A TB skin test only confirms if a person is infected with TB bacteria. It does not inform whether a person has latent TB infection (LTBI) or has progressed to TB disease. A chest X-ray is used to detect abnormalities in the lungs and to rule out the possibility of pulmonary TB. Finally, sputum smear microscopy and culture testing confirm the TB disease. Also, drug resistance tests are highly recommended to provide better treatment.

The direct and indirect costs of getting a diagnosis through various expensive tests and the cost and time it takes to travel act as barriers to the timely diagnosis of TB. Low-and middle-income countries lack a healthcare system where all tests can be performed together and receive quick results. This discourages a potential patient from returning and receiving timely treatment.

How to Diagnose TB in Low-Cost Settings

New technologies have emerged over the past few years to aid in TB diagnosis. These technologies are designed to be low-cost, rapid, and easy to use in low-resource settings. Some of these technologies are:

• Portable imaging software and computer-aided detection (CAD): These tools help with quick reading of chest X-rays, which can be taken using mobile devices or low-cost cameras. The software can detect signs of TB and provide a preliminary diagnosis.
• Cough sounds: This technique uses digital analysis of a forced brief cough session to check whether the person has an increased probability of TB. The cough sounds can be recorded using a smartphone or a microphone and analysed by an algorithm.
• Breath-based diagnostic biomarkers: This method detects molecules in the breath that are indicative of TB infection. The breath samples can be collected using a simple device and analysed by a sensor or a spectrometer.
• Non-invasive techniques: These techniques use samples that are easy to collect and process, such as aerosols, urine, stool, or tongue swabs. These samples can be tested for the presence of TB bacteria or antigens using molecular or immunological methods.
• Fingerstick blood tests: These tests use a small amount of blood from a finger prick to detect antibodies or antigens related to TB infection. The blood samples can be analysed using a paper-based device or a microfluidic chip.

The Future of Low-Cost Solutions

Innovation and testing of new technologies to diagnose TB are showing promising results. The low-cost and quick tests not only save the cost of testing but also aid in timely intervention. Once the effectiveness and evidence of these emerging technologies are established, their use will surely help the burdened healthcare system and prove to be a crucial feature in aiding with TB diagnosis and prevention.