What does a positive acid fast bacillus smear mean?
If your AFB smear was positive, it means you probably have TB or other infection, but an AFB culture is needed confirm the diagnosis. Culture results can take several weeks, so your provider may decide to treat your infection in the meantime.
What is an acid-fast bacteria smear?
Brief Description. Acid- Fast Bacilli (AFB) smear and culture are two separate tests always performed together at the MSPHL, Tuberculosis (TB) Unit. AFB smear refers to the microscopic examination of a fluorochrome stain of a clinical specimen.
What color do acid-fast positive organisms stain?
Acid Fast Strain Acid fast bacteria have a high content of mycolic acids in their cell walls. Acid fast bacteria will be red, while nonacid fast bacteria will stain blue/green with the counterstain with the Kinyoun stain.
What does acid fast stain test for?
The acid-fast stain is a laboratory test that determines if a sample of tissue, blood, or other body substance is infected with the bacteria that causes tuberculosis (TB) and other illnesses.
What diseases can be diagnosed through the acid-fast procedure?
An acid-fast bacteria (AFB) culture is done to find out if you have tuberculosis (TB) or another mycobacterial infection. Besides TB, the other main mycobacterial infections are leprosy and a TB-like disease that affects people with HIV/AIDS.
What bacteria are acid-fast positive?
Bacteria displaying acid fastness include:
- Genus Mycobacterium – M. leprae, M. tuberculosis, M. smegmatis, M. Avium complex, M. kansasii.
- Genus Nocardia – N. brasiliensis, N. cyriacigeorgica, N. farcinica, and N. nova.
What does AFB negative mean?
What Do the Results Mean? If your AFB stain does not have any bacteria that hold onto the dye, then the result is considered negative. This means that you most likely do not have TB or another mycobacterial infection in your lungs.
What is an acid-fast organism?
Excerpt. Acid-fast bacteria, also known as acid-fast bacilli or simply AFB, are a group of bacteria sharing the characteristic of acid fastness. Acid fastness is a physical property that gives a bacterium the ability to resist decolorization by acids during staining procedures.
What diseases are diagnosed using acid-fast staining?
What is this test? An acid-fast bacteria (AFB) culture is done to find out if you have tuberculosis (TB) or another mycobacterial infection. Besides TB, the other main mycobacterial infections are leprosy and a TB-like disease that affects people with HIV/AIDS.
What does acid-fast mean in microbiology?
Acid fastness is a physical property that gives a bacterium the ability to resist decolorization by acids during staining procedures. This means that once the bacterium is stained, it cannot be decolorized using acids routinely used in the process.
Is AFB positive contagious?
A positive AFB culture several weeks after medicine treatment has started may mean the antibiotic is not working and needs to be changed. It also means you are still likely to be infectious and can pass the infection to others through coughing or sneezing.
What can cause a positive AFB?
A positive AFB smear resulting from other bacteria that may have a positive AFB smear, such as Nocardia, Actinomyces, Rhodococcus, Legionella micdadei or cysts of Cryptosporidium species (12, 13).
How should the results of acid-fast microscopy be reported?
The results of acid-fast microscopy may be reported according to the following standards based on the World Health Organization and International Union Against Tuberculosis and Lung Diseases (WHO-IUTLD):For the Ziehl-Neelsen Method (via light/brightfield microscopy) No Acid-fast bacilli (AFB) seen – Report as “0”.
What does an acid fast bacteria smear mean?
A normal result for an acid-fast bacteria smear is negative, meaning no bacteria were found in the sputum sample. A positive result means that bacteria were found and that you may have an infection.
What is AFB smear microscopy?
Terminology •AFB Smear Microscopy: Microscopic examination of specially stained smears to detect acid-fast organisms such as Mycobacterium tuberculosis and non- tuberculous mycobacteria (NTM)
What is the GLI Handbook for acid fast microscopy?
The Global Laboratory Initiative (GLI) handbook for acid-fast microscopy specifies guidelines for reading, recording, and reporting results for both, Ziehl-Neelsen and the auramine methods.[21]