Table 8 Interpretation of the tuberculin sensitivity (Mantoux) test

Table 8 Interpretation of the tuberculin sensitivity (Mantoux) test*

	Induration
Clinical context	<5 mm	5-10 mm	10-20 mm	>25 mm
Screening, non-endemic population	Negative	Suspicious of infection†	90% of patients have infection	Virtually all have infection
Screening, endemic population	Negative	Consistent with past infection†	Suspicious of infection	Suggestive of infection
Following BCG vaccination	Negative	Expected	Suspicious of infection	Suggestive of infection
Chest X-ray suggesting past infection	Negative	Consistent with past infection†	Suspicious of infection	Suggestive of infection
Suspicious clinical findings or contact with active tuberculosis	Negative	Suspicious of infection	90% of patients have infection	Virtually all have infection

* Intradermal injection of 10 Tuberculin units of purified protein derivative (PPD).
† May also be due to cross-reactivity with other mycobacterial species.

Serial tuberculin testing may produce an augmented reaction (booster phenomenon) in those previously sensitised by infection or BCG vaccination.