Tuberculosis (TB) is an infection caused by the bacterium Mycobacterium tuberculosis. It most often affects the lungs but can involve almost any part of the body. India carries about a quarter of the world's TB cases, according to the WHO Global TB Report 2025, yet TB is curable: most people recover completely with a six-month course of medicines, which are free under India's National TB Elimination Programme (NTEP).
Quick answer: A cough lasting two weeks or more, especially with fever, night sweats, weight loss or blood in the sputum, should be tested for TB. The main tests are a sputum molecular test (such as CBNAAT or Truenat), which also checks for drug resistance, and a chest X-ray. Ordinary TB is treated for six months with a combination of four medicines at first, then three. Taking every dose until the end is what cures TB and prevents drug-resistant TB.
Key takeaways
- ✅ Testing and treatment are free at government health centres and designated private facilities.
- ✅ People with TB receive ₹1,000 a month for nutrition under the Ni-kshay Poshan Yojana while on treatment.
- ✅ After about two weeks of correct treatment, most people with lung TB are much less infectious.
- ✅ Close contacts, especially children and people with HIV or diabetes, should be checked too.
How TB spreads and develops
TB spreads through the air when a person with active lung TB coughs, sneezes or talks and others breathe in the tiny droplets. It does not spread through shaking hands, sharing food or utensils. Most people who breathe in the bacteria never become ill: their immune system walls the germs off inside small clumps of cells called granulomas. This is latent TB infection, which causes no symptoms and is not infectious.
In some people, the bacteria break out and multiply, damaging lung tissue and sometimes forming cavities. This is active TB disease. The risk is higher with HIV, diabetes, undernutrition, smoking, alcohol use, kidney failure, steroid or cancer treatment, and in young children and older adults.
|
Latent TB infection |
Active TB disease |
| Symptoms | None | Cough, fever, weight loss and others |
| Infectious? | No | Yes, if in the lungs or throat |
| Sputum test | Negative | Often positive |
| Treatment | Preventive treatment for high-risk groups | Full course of anti-TB medicines |
Symptoms of pulmonary TB
- Cough for two weeks or more, with or without phlegm
- Coughing up blood or blood-streaked sputum
- Fever, often in the evening
- Night sweats
- Unexplained weight loss and loss of appetite
- Chest pain and breathlessness
- Tiredness and weakness
TB outside the lungs (extrapulmonary TB) causes symptoms depending on the site: painless swollen glands in the neck, back pain from spine TB, fluid around the lungs or in the abdomen, or headache, confusion and neck stiffness in TB meningitis, which is an emergency.
TB in children
Children often do not cough up sputum and may not have a typical cough. Warning signs are weight loss or failure to gain weight, persistent fever, reduced playfulness, and a cough that does not settle. Children usually catch TB from an adult at home, so when an adult is diagnosed, every child in the household should be checked. Children under five who live with someone with lung TB are offered preventive treatment once active TB is ruled out. The BCG vaccine given at birth protects young children against severe forms of TB such as TB meningitis.
Tests for tuberculosis
| Test |
What it shows |
| Molecular test on sputum (NAAT: CBNAAT/GeneXpert, Truenat) | Detects TB DNA within hours and checks for rifampicin resistance at the same time. India's programme recommends it as the first test for presumptive TB. |
| Sputum smear microscopy | Looks for acid-fast bacilli under the microscope. Quick and cheap but misses many cases, and cannot detect resistance. |
| Chest X-ray | Shows patches, cavities or fluid. Useful for screening and when sputum tests are negative, but cannot confirm TB alone. |
| Culture and drug-susceptibility testing | Grows the bacteria to confirm TB and test which medicines work. Takes weeks; used mainly for drug-resistant TB. |
| Tuberculin skin test or IGRA blood test | Shows TB infection, but cannot tell latent infection from active disease. |
| Biopsy, fluid tests and scans | Used for extrapulmonary TB, such as a lymph node biopsy or tests on pleural fluid. |
Everyone diagnosed with TB should also be tested for HIV and diabetes, because both change how TB is managed.
Treatment of TB
- Drug-sensitive TB: six months of treatment. The first two months use four medicines (isoniazid, rifampicin, pyrazinamide and ethambutol), followed by four months of three medicines. Fixed-dose combination tablets are given by weight.
- Drug-resistant TB (MDR/RR-TB): uses different medicine combinations, often including newer drugs such as bedaquiline. Shorter all-oral regimens are now used for many patients. Treatment is managed through specialist centres.
- Common side effects include nausea and harmless orange-red urine from rifampicin. Report yellow eyes, persistent vomiting, skin rash, blurred vision or tingling in the feet to your doctor promptly.
Do not stop treatment early, even when you feel well after a few weeks. Stopping or missing doses is the main reason TB comes back and becomes drug-resistant, which is much harder to treat.
Support available in India: free medicines and tests under NTEP, a treatment supporter to help with daily doses, ₹1,000 a month in nutrition support through the Ni-kshay Poshan Yojana (paid by direct bank transfer), and food baskets from Ni-kshay Mitra volunteers in many areas. The TB helpline number is 1800-11-6666.
Preventing TB
- Cover your mouth when coughing and wear a mask during the first weeks of treatment
- Keep rooms well ventilated with windows open
- Get household contacts screened, and take preventive treatment if offered
- Control diabetes, stop smoking, limit alcohol and eat enough protein
- Make sure babies get the BCG vaccine
Frequently asked questions
Is TB curable?
Yes. Drug-sensitive TB is cured in the large majority of people who complete the full course. Drug-resistant TB is also curable, though treatment is more complex.
How long is a TB patient infectious?
Only active lung or throat TB spreads. Infectiousness falls quickly once correct treatment starts, usually within about two weeks, but continue to follow your doctor's advice on masks and ventilation.
Can TB come back after treatment?
It can, especially if treatment was incomplete or immunity is low. See a doctor if cough, fever or weight loss return.
Does TB mean I have HIV?
No. Most people with TB do not have HIV, but HIV testing is recommended for everyone with TB because the two often occur together.
Related reading: HIV/AIDS symptoms, tests and prevention and diabetes symptoms.
Last updated: September 2026. General health information only, not a diagnosis or a treatment plan. Please get tested and follow the treatment advised by a qualified doctor.
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