Figure 5.
The upper pane shows theprobability of a positive RSV PCR test in an infant with bronchiolitis if the RSV antigen test is positiveconditioned on the results of prior RSV antigen tests performed on other infants with bronchiolitis within 24 hours of the case being tested. The lowerpanel shows this if the antigen test is negative. To use this graph: (1) Pick the top panel if the RSV antigen test is positive or the lower panel if the antigen test is negative. (2) Draw a horizontal line from the y-axis at the number of prior negative antigen tests and a vertical line from the x-axis at the number of prior positive antigen tests. The colour where these lines intersect gives the probability that the patient’s PCR test would be positive.