Tuberculosis
Tuberculosis (TB) is a bacterial infection caused by Mycobacterium tuberculosis. It primarily affects the lungs (pulmonary TB) but can also affect other parts of the body including the kidneys, brain and bones.
TB spreads through the air when a person with active pulmonary TB coughs, sneezes or speaks. Not everyone who is infected becomes ill. Latent TB means the bacteria are present in the body but the immune system is keeping them under control, with no symptoms and no risk of spreading the infection to others.
The interferon-gamma release assay (IGRA), such as the QuantiFERON-TB Gold test, is a blood test used to detect TB infection. It works by measuring the immune system's response to TB-specific proteins and is useful for screening people who may have been exposed.
Active TB is treatable with a course of antibiotics, typically lasting six months.
Causes of Tuberculosis
Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. It is an airborne infection spread through tiny droplets released when a person with active pulmonary TB coughs, sneezes, speaks or sings.
Factors that increase the risk of infection and progression to active disease include:
- Close, prolonged contact with someone who has active TB
- A weakened immune system, including from HIV, immunosuppressive medications, malnutrition or diabetes
- Living or working in crowded conditions
- Being born in or travelling to countries with high TB prevalence
- Homelessness, imprisonment and substance misuse
Around a quarter of the world's population is estimated to have latent TB. Only 5 to 10% of those with latent TB will develop active disease during their lifetime, though this risk is much higher in immunocompromised individuals.
Tests that can help check this condition
Learn more on the official NHS page .
