Data analysis
Data are expressed as frequencies and percentages for categorical
variables and means for continuous variables. Agreement
between tests was estimated using Cohen’s kappa (k) coefficient,
while also describing the pattern of disagreement
(discordant results). To aid in the interpretation of agreement
and disagreement, estimates of the prevalence of positive results
are presented. These estimates were compared between
diagnostic tests using the McNemar x2 test for correlated
proportions. The association between each diagnostic test and
the M tuberculosis contact score (high vs low score) was
estimated using logistic regression models, controlling for the
potential confounding effect of age.