If you suspect tuberculosis exposure, a contagious bacterial infection, your doctor may recommend getting a TB test. Learn about the different TB tests, who should be tested, and what the results can tell you about your health.
Recognising the tuberculosis symptoms getting the appropriate screening, such as a Mantoux test, is crucial for early detection and treatment.
Types of TB Tests
There are two main types of tests used to detect tuberculosis infection:
· TB Skin Test (TST or Mantoux Test):
o Involves injecting a small amount of tuberculin beneath the skin of the forearm.
o Measures the immune system's response to TB bacteria.
o Results are interpreted 48-72 hours later by measuring the size of the raised, hardened area (induration).
o Typically recommended for children under 5 and individuals with weakened immune systems.
· TB Blood Test (Interferon-Gamma Release Assay or IGRA):
o Uses a blood sample to evaluate the immune system's response to TB proteins.
o Examples include the QuantiFERON test and the T-Spot TB test.
o Recommended for individuals who may not return for TST reading, those with previous BCG vaccination, or for individuals over 5 years old who have a low or intermediate risk of developing TB.
Purpose of TB Tests
TB tests detect the presence of tuberculosis-causing bacteria in a person’s system. While they can't differentiate between latent and active TB infections, a positive result shows TB bacteria are present, prompting further evaluation to assess tuberculosis symptoms and infection type. TB screening is a crucial tool in public health, aiding in early detection and treatment to curb the spread of TB in communities.
Who Should Get Tested
Certain groups are at a higher risk of contracting tuberculosis or tuberculosis symptoms and should consider getting tested:
· those born in or travelling to TB-prevalent regions
· individuals in congregate settings (shelters, prisons)
· close contacts of TB patients
· healthcare workers
· people with HIV
· those exposed to silica
· communities with limited healthcare access
Procedure for TB Test
The Mantoux test is administered by a healthcare provider trained in both performing the test and interpreting the results. The reaction is measured in millimetres of induration (not redness) on the forearm, measured perpendicular to the long axis.
For TB blood tests, a trained phlebotomist or healthcare provider will will draw a blood sample, which is sent to a lab where a medical technologist will perform the analysis.
Interpreting Test Results
A positive Mantoux test or TB test result suggests possible exposure to the tuberculosis-causing bacteria. However, additional tests, such as chest X-rays and sputum tests, are required to determine whether the infection is latent or active. The interpretation of a positive Mantoux test result depends on the size of the induration and the individual specific risk factors.
A negative result typically indicates the individual has not been exposed to TB bacteria. However, if symptoms of tuberculosis are present, additional testing may be needed to rule out the infection.
Treatment and Prevention
For individuals with latent TB infection (LTBI), a course of anti-tuberculosis medicines is prescribed to prevent the development of active TB disease, particularly if they are at an elevated risk. An active TB disease requires a more extensive treatment plan, including a combination of antibiotics to effectively treat the infection.
TB preventive treatment (TPT) is given to individuals infected with TB bacteria who are at a higher risk of developing active TB disease, to eliminate the bacteria before they cause illness.
Conclusion
TB tests are crucial in identifying tuberculosis infections and reducing their transmission. If you're experiencing Tuberculosis symptoms or belong to a high-risk group, consult your healthcare provider about getting tested.
Remember, the Mantoux test price is a small investment in both your health and the health of others.
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