RESUMO
SETTING: Several studies have indicated considerable variability in the biological results of different tuberculin preparations in different geographical areas or even within a single region. OBJECTIVE: To compare the biological potency of two different tuberculins. DESIGN: We performed simultaneous testing with RT23 and Merieux tuberculin in a group of 546 Police Academy students in Athens to compare reactions to both tuberculins. The students were divided into three groups according to their year of training; the participants in each group were tested using the Mantoux method simultaneously with the two tuberculins in different concentrations. RESULTS: Using a 10 mm cut-off point for a positive tuberculin skin test, positive reactions to RT23 and Merieux were highly correlated. No statistically significant difference was established. The results indicated significant superiority of the size of the reaction with RT23 tuberculin (P = 0.014). CONCLUSIONS: Both tuberculins appear to have equivalent potency, with RT23 more frequently producing reactions of larger sizes.
