This invention relates to a test for detecting a
Mycobacterium tuberculosis (
tuberculosis or TB) infection in a patient or subject, specifically a
diagnostic test, including a
breath test, whereby patients are provided a small
dose of an isotopically labeled TB
drug,
Isoniazid (INH) orally or directly to the lungs of the patient or subject. If TB is present, a TB
enzyme mycobacterial
peroxidase KatG oxidizes the INH; and KatG specific metabolites, in particular, isotopically labeled
nitric oxide (NO), nitrites, nitrates,
carbon monoxide (CO) or
carbon dioxide converted from
carbon monoxide of INH cleavage are measured. Other embodiments relate to a diagnostic
breath test for detecting TB utilizing isotopically labeled
urea (preferably, carbon-13 labeled
urea), alone or in combination with isotopically labeled
isoniazid (preferably,
nitrogen-15 labeled
isoniazid), wherein M.
tuberculosis organism, if present in the patient or subject's lungs (or other tissues), will metabolize the isotopically labeled
urea to isotopically labeled
carbon dioxide (CO2) such that a determination of the
residence of M. tuberculosis, including
residence of an
isoniazid resistant strain of M. tuberculosis, may be made.