Nightingale et al argue that all patients presenting to neurologists with cognitive impairment should undergo HIV testing.1 This view, prompted by a highly unusual case of a patient with HIV-related cognitive impairment, is based on the following reasoning: HIV is potentially treatable and testing is quick and relatively inexpensive; dementia is listed as an indication for testing by the British HIV Association, and suspected encephalitis is an indication for HIV testing in the Association of British Neurologists and British Infectious Association National Encephalitis guidelines; increasing age does not exclude HIV; and HIV is much more common than other ‘routinely’ tested potential causes of dementia, such as syphilis. The authors suggest that clinicians’ reluctance to test for HIV partly relates to misconceptions about the need for extended pre-test counselling.

Undoubtedly HIV can be associated with dementia, is easily tested and potentially treatable. However, before accepting that blanket HIV testing is warranted in all patients with dementia, it is important to consider how most patients with dementia present and the context in which they are seen. The vast majority of individuals presenting with cognitive impairment are elderly, with many—if …