OBJECTIVES: To demonstrate, using the example of a new systematic review of rapid diagnostic tests, how Sankey diagrams, alongside the PRISMA guidelines, can (i) facilitate reporting of the quality of the evidence base and (ii) help assess evidence syntheses when studies use heterogeneous outcomes. METHODS: Systematic review and meta-analysis of experimental and observational studies which included at least one prescribing or clinical outcome of RDTs in hospital in-patients. Sub-group analysis was used to assess heterogeneity in summary effect estimates. A Sankey diagram was then used to show the pattern and quality of evidence on RDT outcomes. RESULTS: 57 studies from 14 countries were included. The introduction of RDTs did not significantly reduce in-hospital mortality (RR 0.83, 95% CI 0.60 – 1.15) or length of stay (weighted mean difference = -0.36, 95% CI -1.67 to 0.96). There was high heterogeneity in outcomes. CONCLUSION: There is no clear evidence that the routine use of RDTs for bacterial identification and antibiotic susceptibility testing improves clinical outcomes in hospital in-patients. Sankey diagrams may be a useful further way succinctly to present the pattern and quality of evidence in systematic reviews, especially when it is heterogeneous and not easily amenable to meta-analysis.