Fig. 4

Likelihood ratios and probability plot for symptoms and signs in predicting skin infections. Likelihood ratios and pre- and post-test probabilities for symptoms and signs in predicting skin infections. Positive and negative likelihood ratios with 95% confidence intervals are presented for each symptom. The black dot within the dumbbell plot represents the pre-test probability of infection (i.e. prevalence). The red dot represents the probability of infection after a positive test (i.e. given that the symptom is present), and the green dot represents the probability of infection after a negative test (i.e. given that the symptom is absent)