1. Clinical Evaluation
- Chronic cough >2–3 weeks
- Fever (often evening rise)
- Weight loss, loss of appetite
- Night sweats
- Hemoptysis (late feature)
2. Sputum Examination (Key for Confirmation)
- Sputum AFB smear (Ziehl–Neelsen stain)
- Detects acid-fast bacilli
- Rapid, inexpensive
- Confirms infectious TB
- Sputum culture (Lowenstein–Jensen / liquid culture)
- Gold standard
- More sensitive
- Takes weeks
- CBNAAT / GeneXpert MTB/RIF
- Detects Mycobacterium tuberculosis DNA
- Identifies rifampicin resistance
- Rapid (≈2 hours)
3. Radiological Tests
- Chest X-ray
- Upper lobe infiltrates
- Cavitations
- Fibrosis, nodules
- Supports diagnosis (not confirmatory alone)
- CT chest (if X-ray unclear)
4. Other Microbiological Samples (if sputum not available)
- Induced sputum
- Bronchoalveolar lavage (BAL)
- Gastric aspirate (children)
5. Immunological Tests (Supportive)
- Mantoux test (Tuberculin skin test)
- Indicates exposure, not active disease
- IGRA (Interferon Gamma Release Assay)
- Supports TB infection, not disease confirmation
6. Histopathology (Selected cases)
- Lung biopsy showing:
- Caseating granulomas
- Langhans giant cells
Final VP Conclusion
Respiratory TB is confirmed by demonstrating Mycobacterium tuberculosis in respiratory samples, most commonly by sputum AFB smear, culture, or CBNAAT, supported by clinical features and chest imaging.