[Diagnostic clinical trial in children using an allergenic extract of Blomia tropicalis].

Background: Blomia tropicalis is a mite that is one of the most important causes of allergic sensitization in studies of tropical and subtropical regions. Nonetheless, there are no published studies of the sensitivity and specificity of B. tropicalis extracts.
Method: An open, non-randomized study was carried out in 205 asthmatic children and in 205 non-asthmatic children, both groups with an age range of 1 to 14 years. Duplicate skin prick tests were made using allergen extracts standardized by biological units and positive and negative controls. The test was considered positive when the average diameter of the wheal was > or = 3 mm and negative when it was < 3 mm. The validity of the test was estimated by calculating sensitivity, specificity, and the positive and negative predictive values.
Results: The skin prick test was positive in 82.92% of the asthmatic children and in 10.7% of the non-asthmatic children, yielding a sensitivity of 82.9%, 95% CI 76.9; 87.7 and a specificity of 89.3%, 95% IC 84.0; 93.0. The positive predictive value was 88.5%, 95% IC 83.0; 92.5 and the negative predictive value was 83.9%, 95% IC 78.2; 88.4.
Conclusions: Blomia tropicalis is an important cause of bronchial asthma among the children of the northern Camagüey region.