On World TB Day 2023, Dr Pavan Asalapuram , Co-founder, EMPE Diagnostics highlights the importance of testing and treating strategy in managing and eliminating TB
As the world battles a multitude of communicable and non-communicable diseases like COVID-19 and diabetes increasingly affirming their presence, another disease that continues to haunt India is Tuberculosis (TB). With an estimated 26 lakh people contracting TB and approximately 4 lakh people dying from it every year, India is home to the highest tuberculosis burden across the globe. In 2021, there was a 19 per cent increase in the number of TB patients in India, with 19,33,381 incident TB patients (new and relapse) notified, compared to 16,28,161 in 2020. Despite decades of progress in fighting this disease, TB has been on the rise in India. However, there is a silver lining: the pandemic has opened new doors to innovative solutions, health-system strengthening, and an ever-expanding reach of public health programmes. Through continuous testing and tracking, we can defeat TB in India and mitigate its implications.
The economic burden of TB is quite substantial and it usually affects the most economically productive age group of society resulting in a significant loss of working days and pushing TB patients further into the vortex of poverty. However, the government of India is committed to eliminating TB in India by 2025 through the National Tuberculosis Elimination Programme (NTEP). Eighteen states have committed to ending TB by 2025 by implementing state-specific strategic plans and devising district-specific strategic plans to guide programme managers and staff at the district and sub-district levels.
Why is the tracking and testing formula instrumental in curbing TB?
The World Health Organization estimates that around 10 million people were affected by TB in 2019, and 1.4 million people died from the disease. Albeit, early detection and timely treatment are crucial in preventing the spread of TB and reducing mortality rates effectively. If one isn’t aware of the existence of tuberculosis, the possibility of eliminating it from the ground level stands zero. Therefore, a systematic tracking approach is a must in order to curb the spread of tuberculosis, particularly in remote areas where regular medical services are unavailable. To expedite tracking, it becomes imperative for government-aided medical facilities and the private healthcare sector to track and identify patients with active symptoms of TB through various mechanisms. Once tracking and identification of places and patients with more susceptibility to tuberculosis, tests should be executed at a large scale. These tests can be done via numerous tests available to diagnose tuberculosis.
Let us now explore what tests are available at the patient’s disposal for TB diagnosis:
Molecular test kit for amplification of M. Tuberculosis: Strongly recommended by WHO, rapid molecular tests enabled kits like mfloDx MDR-TB Kit are user-friendly diagnostic tests that can provide immediate confirmatory results, reducing the time required to initiate effective therapy for TB patients significantly. In some kits, results even arrive within 3 hours of the time frame. Besides rapid results, these TB diagnostic kits are inexpensive, easy to interpret and perform multiplex molecular tests with no advanced instrument required. Moreover, they provide an instant outcome for Rifampicin and Isoniazid drug resistance so that patients can avail of effective antibiotic treatment and limit the transmission of drug resistance.
Interferon-Gamma Release Assays (IGRAs)
Interferon-gamma release assays (IGRAs) represent blood tests that detect the presence of specific proteins produced by the immune system in response to TB bacteria and are available in two types: the QuantiFERON-TB Gold In-Tube test (QFT-GIT) and the T-SPOT.TB test. Both tests involve drawing blood from the patient and measuring the amount of interferon-gamma released by the immune system in response to TB antigens. IGRAs are more specific than the TST and can be used in individuals who have been vaccinated with BCG. However, they are more expensive than TST and require specialized laboratory equipment.
Chest X-ray is an imaging test that produces pictures of the chest, including the lungs and surrounding tissues. It can detect abnormalities in the lungs, such as nodules, cavities, or infiltrates, which may indicate the presence of TB. However, chest X-ray cannot differentiate between active and latent TB infections and is not suitable for diagnosing TB in asymptomatic individuals.
Sputum smear microscopy
Sputum smear microscopy is a simple and inexpensive test that involves examining sputum samples under a microscope to detect the presence of TB bacteria while the samples are collected from the patient by asking them to cough up sputum, which is then stained with a special dye and examined under a microscope. Sputum smear microscopy is widely used in resource-limited settings but has a low sensitivity for detecting TB, especially in individuals with HIV co-infection.
Culture and sensitivity testing
Culture and sensitivity testing involves growing TB bacteria from sputum or other body fluids in a laboratory and testing them against various antibiotics to determine which drugs are most effective in treating the infection. This method can provide a definitive diagnosis of TB and also determine drug resistance patterns. However, culture and sensitivity testing is expensive, time-consuming, and requires specialized laboratory equipment and trained personnel.
Tuberculin Skin Test (TST)
Also known as the Mantoux test, it is one of the oldest and most widely used diagnostic tests for tuberculosis which involves injecting a small amount of purified protein derivative (PPD) into the skin and observing the reaction after 48 to 72 hours. If the person has been infected with TB, their immune system will react to the PPD, resulting in a raised, red, and itchy bump at the site of injection. The size of the reaction is measured in millimetres, and a positive reaction is defined as a bump that is 5 mm or larger. However, TST has some limitations as it cannot differentiate between current or past infections and can be affected by other factors like BCG vaccination.
The diagnosis of tuberculosis has long been a challenge for medical professionals worldwide. It is a serious global health problem and is one of the top 10 causes of death worldwide. To tackle this global health crisis, scientists and healthcare professionals continue to explore new and innovative methods for diagnosing and treating TB and diagnostic kits for TB like mfloDx MDR-TB Kit can prove crucial in combatting the disease. To sum up, the fight against TB in India is a long one, but continuous testing and tracking of TB patients can help mitigate its implications. It is imperative to reach the unreached and targeted groups through active case finding for early detection of TB cases and initiating prompt treatment.