- Call: +919990304304
- Email: info@drvikasmittal.com
Sputum AFB stain is a microscopic test used to detect Mycobacterium tuberculosis (TB bacteria) in the sputum. “AFB” stands for Acid-Fast Bacilli, which are bacteria that retain special stains even after being washed with acid, a characteristic of TB bacteria.
To diagnose active pulmonary tuberculosis in patients with symptoms such as:
Cannot detect drug resistance or differentiate between dead and live bacteria.
Sample Collection:
Lab Procedure:
Breathe deeply and cough from the lungs, not throat.
It is a gold-standard test to detect and confirm the presence of tuberculosis (TB) and other mycobacterial infections by growing the bacteria from sputum or other body samples. The AFB culture is a laboratory test where a patient’s sample (usually sputum) is placed in a special medium to grow Mycobacterium tuberculosis, the bacteria that causes TB.
To perform drug susceptibility testing (DST) and check for drug-resistant TB.
Sample Collection:
Culture Method:
If TB grows, further testing is done to confirm the type of bacteria and its drug resistance.
GeneXpert is a molecular test that detects the DNA of Mycobacterium tuberculosis in a patient’s sample, usually sputum. It also tests whether the bacteria are resistant to rifampicin, a key anti-TB drug. It gives the result within 2 hours.
Sample Collection:
Laboratory Procedure:
It is a laboratory test which is used to identify the bacteria in a clinical sample and determine the most effective antibiotic for treatment. The Gram stain and culture is a common laboratory test performed on body fluids like sputum, blood, urine, or wound discharge to visualize the bacteria under a microscope (Gram stain), grow bacteria in a controlled lab environment (Culture) and identify the exact bacteria and test which antibiotics work against it (Sensitivity testing).
It is commonly used in:
Gram Stain:
Culture:
Sample Collection:
Gram Staining:
Culture Process:
Colonies are tested for identification and sensitivity.
No. At least two or three samples are needed. TB may be missed if only one is tested.
Doctors may use nebulisation to help loosen secretions (induced sputum), or perform a bronchoscopy if needed.
Because TB bacteria grow very slowly, especially in solid media. Liquid culture methods are faster but still take at least a week.
Yes. Culture is more sensitive, and some people (especially those with low immunity) may have smear-negative but culture-positive TB.
AFB stain looks for TB bacteria under a microscope and is less sensitive. GeneXpert uses DNA technology, is faster and more sensitive, and also detects drug resistance.
Not always. If suspicion is strong, other tests (e.g., TB culture, imaging) may still be needed, especially for extra-pulmonary TB.
These terms describe how bacteria react to staining and help in choosing antibiotics. For example, Streptococcus is Gram-positive, while Pseudomonas is Gram-negative.
Then the infection is viral or fungal. Antibiotics were taken before giving the sample. The sample was inadequate or contaminated.