Medical professionals and a sexual health charity say doctors in parts of the UK where HIV infections rates are higher than normal, are failing to follow testing guidelines.
Doctors from Britain's largest NHS trust, Barts Health say the biggest barrier to screening for the virus is often clinicians themselves.
The National Aids Trust has supported the claims. The charity says one in five people living with HIV remain undiagnosed and almost half are diagnosed late.
The Department of Health says its sexual health strategy focuses on prevention and testing, but says the NHS and local authorities need to work together to make sure services work for patients.
28 year old Tom was diagnosed in 2011. There's more about his story here..
Doctor Chloe Orkin is from the Royal London Hospital. In this video she explains how an HIV test works, and how you can get one.
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