BACKGROUND There is good evidence from multiple sites, including in Ghana, that malaria is massively over-diagnosed. It could be argued that where microscopy is not available it can be introduced, and elsewhere it can be improved, but high-quality microscopy is not easy to sustain. If substantial over-diagnosis continues in Ghana in an era where an ACT is now the first-line treatment, it will lead to the intervention being substantially more expensive due to over-prescription than it should be, potentially rendering it unsustainable.