Tuberculosis (TB)

Note: Complete management of tuberculosis is beyond the scope of this book. See Canadian Tuberculosis Standards.

Recommend investigation for TB in adults if:

  • symptoms of:
    • cough > 2-3 weeks
    • hemoptysis
    • fever/night sweats
    • anorexia/weight loss
  • high risk:
    • foreign-born (Asia, Africa, Latin America)
    • First Nations
    • elderly
    • homeless
    • immunocompromised/HIV
    • epidemiologic link to active TB case
  • chest x-ray with upper lobe cavity or fibronodular infiltrate.

- If suspect TB, place patient in negative pressure respiratory isolation until sputum AFB smear negative on 3 consecutive days.


  • Chest x-ray
  • Sputum for AFB smear and culture (collect on 3 consecutive days).

NB: Do NOT use tuberculin skin test (TST) or Interferon Gamma Release Assay (IGRA) for diagnosis of active TB. These are used to diagnose latent TB infection and cannot distinguish active from latent infection.

- If AFB smear/culture positive for M. tuberculosis complex, initiate therapy and report case to Public Health. Test for HIV infection.

- Strongly consider directly observed therapy (DOT) via Public Health, especially for HIV co-infection, MDR/XDR TB, sputum smear positive pulmonary TB, and nonadherence.

- If history of previous TB treatment or contact with drug-resistant TB*, consult TB specialist.

* Multi-drug resistant TB (MDR-TB) = resistance to at least isoniazid and rifampin.

Extensively drug-resistant TB (XDR-TB) = resistance to isoniazid and rifampin and fluoroquinolone plus at least one of the three second-line injectable aminoglycoside drugs (capreomycin, kanamycin, or amikacin).

- Monitor for drug toxicity:

  • CBC with differential, ALT, AST, bilirubin, urinalysis, serum creatinine at baseline and every 1-2 weeks
  • Increased monitoring recommended in patients at risk for hepatotoxicity:
    • pre-existing liver disease
    • history of alcohol use disorder
    • ≥ 35 years of age

Patients should be instructed to watch for signs of hepatitis (nausea, vomiting, stomach pain, lack of appetite, fatigue, dark urine, jaundice).

  • visual acuity (Snellen chart)/color vision (isochromatic plates) baseline and monthly while on ethambutol.
Usual Pathogens

M. tuberculosis


Empiric Therapy Dose Duration
Isoniazid (INH) 5mg/kg PO daily or 5 times per week (max 300mg/dose) See Duration
Rifampin 10mg/kg PO daily or 5 times per week  
Pyrazinamide 20-30mg/kg PO daily or 5 times per week (max 2g/dose)  
Ethambutol 15-25mg/kg PO daily or 5 times per week (max 1.6g/dose)  
Pyridoxine (vitamin B6) 25mg PO daily