HIV testing services have been scaled up considerably worldwide. Between 2010 and 2014 more than 600 million people received HIV testing services in 122 low- and middle- income countries (LMIC). In 2017, it was estimated that, globally, 75% of people with HIV were aware of their HIV- positive status, an increase from 67% in 2015. Despite this progress, 9.4 million people – 25% of all people with HIV – remain unaware of their HIV infection. Many of those not currently benefiting from HIV testing scale-up are key populations, men and young people (aged 15–24).