Tuberculin reaction in pulmonary tuberculosis in the Asir Region of Saudi Arabia.

The Mantoux test was performed on 75 Saudi and Yemeni patients with pulmonary tuberculosis using 2TU of PPD-RT23; 82.7% of these patients had a positive skin test. It was also noted that, contrary to findings in the West, old age does not seem to affect the Mantoux reaction adversely. 9 patients had a non-significant reaction and using the 3-step 'boosting', 8 of the 9 (88.9%) non-reactors converted to positive. Despite the low number of patients included in our study, we recommend 3-step 'boosting' when doing tuberculin skin testing in Third World Countries in order to bring out the true tuberculin 'reactors'.