[Reduction of excessive reactions after tuberculin skin test (mendel-mantoux method)].

In 2.5 % of cases excessive reaction with formation of blisters and local necrosis is seen after tuberculin skin testing with Mendel-Mantoux technique. The objective of this prospective study was to determine whether this rate can be reduced by pretesting. 426 contacts of cases with contagious pulmonary tuberculosis were examined in a public health office. A tuberculin skin test in Mendel-Mantoux technique with 1 unit purified tuberculin Behring (GT 1, bioequivalent to 0.5 units PPD-S) was applied and the results read after 3 to 7 days. Negative results were retested with 10 units (GT 10, bioequivalent to 5 units PPD-S). 422 patients completed the examination course as planned. In two cases forming of blisters was noticed. The difference between this observed rate of 0.5 % and the published rate of 2.5 % is highly significant. The alternative hypothesis that pretesting reduces the rate of excessive reactions can be assumed.