Tuberculosis screening or TB screening is a worldwide program promoted by health experts in order to curtail the spread of pulmonary tuberculosis. It is a health screening test often done to identify individuals with a TB infection and those suffering from active pulmonary tuberculosis, and to give them appropriate treatment. The TB screening test also investigates close contacts of those found positive for tuberculosis, including each member of their households. This is an important method to catch TB infection and to give proper treatment in order to prevent the disease from becoming active and contagious. The TB screening test often includes a skin test, called the Mantoux test, where a small amount of purified protein derivative (PPD) is injected just under the skin of the forearm. After 48 to 72 hours, the physician checks for any reactions, which can indicate infection with TB. Other important TB screening tests include chest X-rays, blood tests, sputum smears, and sputum cultures. Pulmonary tuberculosis is an infection of the lung caused by the bacteria Mycobacterium tuberculosis. Symptoms of active pulmonary TB include fever, unexplained loss of weight, nights sweats, fatigue, and persistent cough. Sufferers sometimes cough up blood, and chest pain may accompany breathing or each bout of coughing.
When people with active TB cough, spit, speak, or even sing, they expel TB bacteria into the air. Close contacts of TB patients may inhale these bacteria, which can gain access to either one or both lungs, causing TB infection. When a person is healthy, his immune system can generally kill the bacteria or wall them off in the lungs, preventing the disease from becoming active. These bacteria in the lungs can lie dormant for many years, until the individual's immune system weakens for any reason. The TB bacteria can then multiply in the lungs, making the person infectious and often manifesting with the signs and symptoms of active TB. People who show signs and symptoms of active TB should immediately consult a lung specialist or pulmonologist. If the specialist suspects tuberculosis, he will usually order a TB screening test. When the patient becomes positive for TB, his family members and close contacts will also need to undergo TB screening in order to determine where the TB came from and to identity if any of them are infected as well. A person with active TB may infect as many as 10 to 15 people annually if left untreated.
How is it used?
TB screening tests are not used as a general population screens but are used to screen certain people who are at high risk for TB exposure, such as: * Those who have signs and symptoms consistent with active tuberculosis * Those with diseases or conditions that weaken the immune system, such as those with HIV or AIDS , that make them more vulnerable to a TB infection * Those who are in confined living conditions such as homeless shelters, migrant farm camps, nursing homes, schools, and correctional facilities * Health care workers and others whose occupations bring them in close contact with those who may have active TB * Those who have been in close contact with someone who has an active case of TB * Those who come from or have lived for a period of time in a foreign country where TB may be more common * Those who inject illegal drugs
TB screening tests are also used sometimes as part of a routine examination prior to starting school or a new job. Since mothers can pass TB to their unborn children, pregnant women are sometimes screened. Testing is used to help diagnose a Mycobacterium tuberculosis infection, either a latent TB infection or active disease. If the doctor suspects that a person has active tuberculosis, other tests, such as chest X-rays and AFB smears and cultures, are used to confirm the diagnosis. Either a tuberculin skin test or an IGRA may be performed. IGRA tests are relatively new and are not performed by all...