Investigations

Investigations
Pulmonary TB:

• Chest X-ray (cavitations, pleural effusions, mediastinal or hilar lymphadenopathy, parenchymal infiltration in upper lobes)
• 3 sputum samples if X-ray suggestive

Extrapulmonary TB:

• Above investigations plus site-specific:
• MSU
• Echo
• Skeletal X-rays
• Abdominal ultrasound

Screening methods:

Mantoux skin test: positive if ≥5mm induration

IGRA blood test: detects white cell response to TB antigens

• Rapid diagnostic NAAT for HIV patients/urgent contact tracing

*Screening patients who are asymptomatic but at high risk includes:

1. Had contact w/ someone who has active TB
2. Immunocompromised
3. New entrants to the UK from highly prevalent areas
4. New NHS employees working with patients +/- clinical specimens
5. Has evidence of TB scarring or untreated fibrotic changes on CXR