From each article, data on sensitivity, specificity, negative and positive predictive value was obtained. In cases where these values were not presented by the authors, contingency tables were created in order to find them.
De cada artículo se obtuvieron datos de sensibilidad, especificidad, valor predictivo positivo y negativo; en caso que no fueran expuestos estos valores por los autores se realizaban tablas de contingencia para poder hallarlos.