Tuberculosis: Screening Flashcards
1
Q
What is the main technique used to screen for latent TB?
A
The Mantoux test.
2
Q
In recent years, what other test has been used to detect latent TB?
When might it be used?
A
Interferon-Gamma Blood Test
- The Mantoux test is positive or equivocal
- People where a tuberculin test may be falsely negative
3
Q
Tell me about how the Mantoux test is injected, how much, when & how to interpret it?
A
- 0.1 ml of 1:1,000 purified protein derivative (PPD) injected intradermally
- result read 2-3 days later
- < 5mm - negative. If unvaccinated can be given BCG.
- 5-15mm - Should not be given BCG - may be due to TB infection or BCG. Consider Interferon Gamma Release Assay.
- >15mm - strongly positive - suggests TB infection.
4
Q
What can cause the Mantoux test to be falsely negative?
A
- Miliary TB
- Sarcoidosis
- HIV
- Lymphoma
- Very young age (e.g. < 6 months)
5
Q
What test is no longer used?
A
The Heaf test
