The OptTEST by HiE project (Optimising testing and linkage to care for HIV across Europe) was a three year project co-funded by the EU Commission under the Second Health Programme. The project ran from 1 July 2014 to 30 September 2017 and aimed to help reduce the number of undiagnosed people with HIV infection in the European region and to promote timely treatment and care. The project has produced tools and assessment methods to analyse and effectively respond to late presentation for HIV care and treatment, with a particular emphasis on priority regions and groups throughout Europe.