1st August 2023

Diagnosis

HIV infection can be symptomatic or asymptomatic and may be detected through screening or following investigation of suspicious clinical features.

Clinical features

Primary HIV infection (or seroconversion illness) refers to the non-specific flu-like illness that may present in the first six months following infection. It generally manifests within the first six weeks when the immune system reacts to the virus and produces antibodies. The common features are fever, sore throat, malaise, lethargy, arthralgia, myalgia, and a maculopapular rash.

Long-term HIV infection may cause constitutional features such as fever, weight loss, night sweats and lymphadenopathy.

HIV may also manifest with the features of associated illnesses as the initial presentations (see Complications section below).

NICE recommends that HIV be suspected in patients presenting with prolonged or recurrent infections, any conditions recognised as complications, unexplained weight loss, unexplained lymphadenopathy, or pyrexia of unknown origin.

Testing

The first line HIV test in the UK is a dual test for the HIV antibody and p24 antigen (HIV viral material). Point-of-care antibody tests can give results within minutes, but should always be followed up by confirmatory serological testing.

There is a roughly six week latency period between the initial infection and the time at which the serological test becomes positive. Therefore, if an individual has been exposed and initially tests negative, repeat tests at this time interval may be indicated. Currently, the window period in which HIV tests may be negative despite the individual being infected is 45 days – therefore, negative tests before this interval may be inaccurate.

All individuals with symptoms suspicious of HIV infection should be tested, and screening tests also offered opportunistically to at-risk individuals, such as men who have sex with men (MSM), female sexual contacts of MSM, sex workers, intravenous drug users, prisoners, people from countries with a high prevalence of HIV, and people reporting sexual contact with individuals from a country with a high prevalence of HIV.

Specific verbal consent must be given for an HIV test, and a patient cannot be tested without their consent. Permission to disclose positive test results to other healthcare professionals – such as a patient’s GP – must also be specifically sought and can be refused.