These consolidated guidelines on HIV testing services (HTS) bring together existing and new guidance on HTS across different settings and populations. The World Health Organization (WHO) first released consolidated guidelines on HTS in 2015, in response to requests from Member States, national programme managers and health workers for support to achieve the United Nations (UN) 90–90–90 global HIV targets – and specifically the first target of diagnosing 90% of all people with HIV. In 2016, based on new evidence, WHO released a supplement to address important new HIV testing approaches – HIV self-testing (HIVST) and provider-assisted referral. Since the release of 2015 and 2016 HTS guidelines, new issues and more evidence have emerged. To address this, WHO has updated guidance on HIV testing services. In this guideline, WHO updates recommendation on HIVST and provides new recommendations on social network-based HIV testing approaches and western blotting (see box, next page). This guideline seeks to provide support to Member States, programme managers, health workers and other stakeholders seeking to achieve national and international goals to end the HIV epidemic as a public health threat by 2030. These guidelines also provide operational guidance on HTS demand creation and messaging; implementation considerations for priority populations; HIV testing strategies for diagnosis HIV; optimizing the use of dual HIV/syphilis rapid diagnostic tests; and considerations for strategic planning and rationalizing resources such as optimal time points for maternal retesting