AFB, Smear Test

AFB is Acid-fasting Bacillus, acid-fasting is the property of certain bacterial cells. The AFB Smear test is carried out when a person is suspected to have Tuberculosis. The tuberculosis infection is caused by the Mycobacterium tuberculosis AFB. The test is carried out by taking the sample from the patient and is the fastest yet effective tests available to detect tuberculosis. The negative test results means that the infection is not present in the patient. A positive AFB test result indicates the presence of mycobacteria in the sample. The negative sample may contain infection and is therefore the sample is still allowed to grow in the culture.

AFB smear is the fastest test available to detect the infection which may cause tuberculosis. The test detects for positive or negative presence of the mycobacteria. The sample collected from the patient is spread on a thin glass slide. A particular dye is added to the sample which will stain the mycobacteria and can be spotted clearly on the slide, under the microscope, if present. The mycobacteria are easy to locate due to their high mycolic acid content of their cell wall. This mycolic acid is stained due to the dye because of its poor absorption and higher retention quality.

If someone is experiencing coughing from several weeks then it is advised to get them tested for potential TB. The doctors advise to undergo AFB smear to check for the mycobacterial infection or other lung infections. The test is helpful to detect the following diseases: Chronic cough producing phlegm, Lingering, Fever, Loss of appetite, Spinal TB, Bone marrow TB, TB meningitis, Joint and abdominal pain.

Before undergoing the AFB smear test the patient should drink lots of fluids the night before the test. The fluids can be water, tea, coffee, etc. The inclusion of fluids helps your body to create more sputum and the night before the test will do the same. The more the sputum the more accurate will be the results. Bacteria are present in a high number during the morning time.