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The presumptive TB testing rate in the country increased from 1,352 per lakh population in 2022 to 1,710 per lakh population in 2023.
Even two years before the 2025 deadline that the government has set to “eliminate” TB in India, only 21% of presumptive TB testing in 2023 was upfront done using a rapid molecular diagnostic test.
According to the India TB Report 2024, which is yet to be made public, at 79%.
The vast majority of presumptive TB testing was still carried out using the 100-year old sputum smear microscopy, which has low sensitivity.
Ironically, compared with 2022, there has actually been a marginal decrease from 23% to 21% in the percentage of presumptive TB testing offered upfront using a molecular test in 2023.
Smear Microscopy
Smear microscopy is a rapid and relatively simple technique used in laboratories to diagnose various infections and conditions.
A biological sample is collected from the patient, depending on the suspected condition.
This could be sputum (cough mucus) for diagnosing respiratory infections, vaginal fluid for Pap smears to detect cervical cancer, or a swab from a wound or sore.
The sample is thinly spread onto a glass slide, creating a smear.
This allows for better visualization of cells or microorganisms under the microscope.
The smear is air-dried and then heat-fixed to ensure the cells or organisms adhere to the slide.
The smear is treated with specific dyes that bind to different components of cells or microorganisms.
This staining process enhances contrast and makes them easier to identify under the microscope.
Different stains are used depending on the suspected diagnosis.
A Ziehl-Neelsen stain is used to identify Mycobacterium tuberculosis (TB) bacteria, while a Papanicolaou stain (Pap stain) is used in Pap smears.
A trained technician examines the stained smear under a microscope to identify the presence, type, and quantity of cells or microorganisms.
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