Micro & Immunology · single question
What is the Mantoux test used for?
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Correct answer: A. Tuberculosis (TB) screening
Tuberculosis (TB) screening (A). The Mantoux tuberculin skin test (TST):
• 0.1 mL of purified protein derivative (PPD) injected intradermally
• Read at 48-72 hours — induration (not erythema) is measured
• Positive cutoffs: ≥5mm (HIV+, close contacts, immunosuppressed), ≥10mm (HCWs, recent immigrants, prisoners, high-risk populations), ≥15mm (low-risk individuals)
• A positive TST indicates TB infection (latent or active) — NOT disease confirmation (chest X-ray + sputum culture needed).
• BCG vaccination causes a false positive result.
• OSHA requirement: HCWs should have annual TB testing (though QuantiFERON Gold blood test is now preferred).
• Dental offices should screen all patients for TB symptoms at each visit.
• 0.1 mL of purified protein derivative (PPD) injected intradermally
• Read at 48-72 hours — induration (not erythema) is measured
• Positive cutoffs: ≥5mm (HIV+, close contacts, immunosuppressed), ≥10mm (HCWs, recent immigrants, prisoners, high-risk populations), ≥15mm (low-risk individuals)
• A positive TST indicates TB infection (latent or active) — NOT disease confirmation (chest X-ray + sputum culture needed).
• BCG vaccination causes a false positive result.
• OSHA requirement: HCWs should have annual TB testing (though QuantiFERON Gold blood test is now preferred).
• Dental offices should screen all patients for TB symptoms at each visit.
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