Tuberculin sensitivity test
In vivo test.
Intradermal injection of 5 Tuberculin units of purified protein derivative (PPD) is the preferred technique for quantitation of response.
Multiple puncture techniques (Heaf and Tine tests) are also alternatives by trained operators.
The reaction is read at 48-72 h.
|Reference Interval:|| |
Negative test defined as < 5 mm induration.
Investigation for exposure to, or infection with, Tuberculosis.
This test is contraindicated in patients with a history of a previous excessive reaction.
A positive test indicates that the patient has been infected with Mycobacterium tuberculosis or with an atypical Mycobacterium sp.
It is consistent with both previous exposure or active infection.
A positive result may also indicate previous BCG vaccination, and results should be interpreted in the light of the vaccination history. See Table 7.
In a patient with known or suspected immune deficiency, a negative result should be interpreted in conjunction with the results of delayed hypersensitivity skin tests.
Tiruviluamala P and Reichman LB. Immunol Allergy Clin North Am 1993; 13: 59-75.
Tala-heikkela M et al. Tuber Lung Dis 1992; 73: 330-335.
Australian Technical Advisory Group on Immunisation. The Australian Immunisation Handbook. 10th ed. 2013. Canberra: Australian Government Department of Health.