AFB Sputum Microscopy: Bacillary Burden Threshold
Direct microscopy for detecting Acid Fast Bacilli (AFB) in sputum requires a significant number of bacteria present to be reliably identified.
Understanding AFB Detection Limits
The sensitivity of direct sputum microscopy is limited. A certain minimum concentration of AFB is necessary for them to be visible under the microscope.
- Lower concentrations of AFB may be missed, leading to false-negative results.
- Higher concentrations increase the likelihood of detection.
Typical Bacillary Burden for Detection
For AFB to be typically detected using direct microscopy in sputum samples, the bacillary burden usually needs to be in the range of 5,000 to 10,000 organisms per milliliter of sputum.
This concentration corresponds to option B.
Important Questions from Tuberculosis
A 65-year old man, on Warfarin treatment, is started on antitubercular treatment. The pharmacologic effect of Warfarin is likely to:
- The Gene X-pert test used for MTB detection has the additional advantage of detection of which of the following?
- Recommended first time drug for initial treatment of tuberculosis include all EXCEPT:
The most frequent adverse reaction of significance among people treated for drug-susceptible tuberculosis is:
All adult patients in whom anti-tubercular treatment is being started should undergo baseline assessment of:
