RESUMEN
Skin testing with antigens from M. tuberculosis (PPD-S) and various atypical mycobacteria was carried out in Somalia among 170 patients with active tuberculosis. Percentage of positive reactons (5 mm or greater) was 70,58% with PPD-S, 60,0% with the antigen from M. africanum and M. scrofulaceum, 56,47% with the antigen from M. xenopei, 10,58% with the antigen from N. otididis and 4,50% with the antigen from N. farcinica. The percentage of subjects in whom the reaction with the antigen from M. africanum was greater than with PPD-S was 10,58%; more precisely in a percentage of 16,0% the skin testing from M. africanum was positive against a negative reaction to PPD-S, meanwhile in a percentage of 8,33% both skin tests were positive, with a greater reaction for a M. africanum test. As far as other antigens are concerned at least one of these tests was greater on the 28,23% the PPD-S one.