A Mantoux test is performed on a patient being screened for tuberculosis. An induration of 15 mm is measured at 48-72 hours. The patient received BCG ...

Question

A Mantoux test is performed on a patient being screened for tuberculosis. An induration of 15 mm is measured at 48-72 hours. The patient received BCG vaccination as a child. What is the role of IGRA (interferon-gamma release assay) in this scenario?

Accepted Answer

IGRA is more specific than Mantoux as it uses M. tuberculosis-specific antigens (ESAT-6 and CFP-10) that are absent from BCG strains, reducing false positives from prior BCG vaccination

Answer

IGRA is less specific than Mantoux and cannot distinguish BCG from TB infection

Answer

IGRA and Mantoux have identical performance in BCG-vaccinated individuals

Answer

IGRA is only useful in children under 5

Answer

IGRA requires sputum samples

uk-dtmh MCQ (SBA): IGRA vs Mantoux in BCG-vaccinated

A Mantoux test is performed on a patient being screened for tuberculosis. An induration of 15 mm is measured at 48-72 hours. The patient received BCG vaccination as a child. What is the role of IGRA (interferon-gamma release assay) in this scenario?