Synonyms/Also Known as
Tissue AFB Smear, Tissue Mycobacteria Smear, Tissue TB Smear
TB Screening Tests, Susceptibility Testing, Adenosine Deaminase
Why get tested?
Helps to detect the infections that are caused by Mycobacterium tuberculosis and other mycobacterium species and to monitor the effectiveness of treatment.
When to get tested?
When there are signs and symptoms such as weight loss, loss of appetite, chronic cough, fever with evening rise of temperature, chills, enlarged neck nodes (lymph nodes), weakness, etc., when suspecting tuberculosis, when TB screening test is positive, when exposed to the person diagnosed with tuberculosis, etc.
Test preparation needed
No special preparation required
About The Test
How is it used
1. When is AFB test done?
When a person has symptoms such as chronic cough, weight loss, fever - evening rise of temperature, chills, loss of apetite, enlarged lymph nodes and weakness, when suspecting tuberculosis. When TB screening test is positive and to monitor effectiveness of treatment for Tuberculosis.
2. Can the tuberculosis infection be Asymptomatic?
Yes. Usually with active tuberculos infection will be symptomatic and manifest with symptoms like loss of weight, loss of apetite, fever, cough, chills etc. But when the tuberculosis infection is latent, persons can be asymptomatic.
3. What all organisms are detected by AFB stain apart from Mycobacterium tuberculosis?
Mycobacterium avium-intracellulare complex (MAC), Mycobacterium marinum, Mycobacterium fortuitum, Mycobacterium bovis, Nocardia species etc.
4. How is a AFB smear interpreted?
When the AFB smear is examined under microscope, if acid-fast bacilli (Mycobacterium) are found, it is reported as positive and graded according to the RNTCP guidelines. At least 100 oil immersion fields are examined before reporting the AFB stain as negative.