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All patients whose sexual or drug injection history indicates the recommendation or consideration of pre-exposure prophylaxis (PrEP), and who are interested in taking PrEP, must undergo laboratory testing. The tests identify those for whom this intervention would be harmful, or in whom it could present specific health risks that would require close monitoring.

HIV testing

For patients’ safety, those with acute or chronic human immunodeficiency virus (HIV) infection should be identified through taking a medical history and HIV testing. A negative HIV test result must be documented at the time the patient is evaluated for PrEP as the daily, or on-demand^† tenofovir disoproxil* and emtricitabine (TD*/FTC) combination alone is insufficient for treatment of acute or chronic HIV infection.

HIV testing must be repeated every 3 months when patients attend for a prescription refill. This requirement for quarterly visits should be explained to patients during the initial discussion about whether PrEP is appropriate for them.

A fourth-generation HIV antibody/antigen venous blood test should be used and should be performed within 7 days of the patient being evaluated for PrEP. Clinicians should tell patients to start PrEP within 7 days of the day that their HIV-negative test was performed.

Rapid, point-of-care tests (PoCT) should not be used alone to screen for HIV infection when considering PrEP because they are less sensitive than blood tests. Failure to detect very early HIV infection by rapid testing in the PrEP context has been reported (1). This includes the Atomo HIV Self-Test, a rapid homebased HIV testing kit which was approved for online purchase in Australia by the TGA in November 2018. However, a rapid PoCT can be used for the same day initiation of PrEP providing that a venous blood test for a fourth generation HIV antibody/ antigen test is obtained and tested simultaneously. A PoCT can exclude potential PrEP users who are found to be HIV positive, and any reactive PoCT should be confirmed by conventional laboratory testing in line with the Australian HIV Testing Policy. Clinicians should not accept patient-reported HIV test results, including home-based HIV test results, or documented anonymous test results. Any positive HIV antibody test result must be managed according to the Australian HIV Testing Policy and local management guidelines (www.testingportal.ashm.org.au).

A course of non-occupational post-exposure prophylaxis (nPEP) may be required before transitioning to PrEP, in accordance with the PEP and nPEP guidelines (2) if a patient has had a recent high-risk exposure (within 72 hours). See the PEP guidelines for more information.

Patients who have had a recent high-risk exposure outside the 72 hour window for the commencement of nPEP should be started on PrEP and closely monitored for seroconversion using a fourth-generation HIV test for the next 2–8 weeks before reverting to standard PrEP monitoring. HIV viral load and HIV proviral DNA tests are not recommended to screen for early HIV infection. These tests are not reimbursed by Medicare and may take 10-14 days for results to be available.

Acute HIV infection should be suspected in individuals at high risk of HIV who may have had recent exposure to HIV (e.g. no condom or a condom broke during sex with an HIV-positive partner not on treatment, or casual partner of MSM; recent injecting drug use with shared injection equipment with MSM, or person known to be HIV positive).

In a prospective study of 2,226 people at high risk of HIV infection who underwent twice-weekly HIV nucleic acid testing, 50 people were evaluated for their clinical signs and symptoms during acute HIV infection. Symptoms and signs occurred in 94% of participants with acute HIV infection, just before and around the time of peak HIV viraemia (3). The most common symptoms were fever, headache and malaise, while the most common signs were related to the head, eyes, ears, nose, throat, tachycardia and lymphadenopathy (Table 5.1).

Table 5.1 Symptoms and abnormalities associated with primary or acute HIV infection, overall and by region (3).

^aHead, ears, eyes, nose and throat^.

^bA condition or disease affecting the lymph glands of the body resulting in lymph nodes that are abnormal in size, consistency or number

Initiation of TD*/FTC PrEP in individuals with undiagnosed primary or acute (symptomatic) HIV infection has been associated with the development of resistance to TD*/FTC, mostly commonly to the FTC component (4-7).

People who present with signs or symptoms consistent with acute HIV infection should not be commenced on PrEP until HIV infection has been excluded. 2019

Patients with indeterminate HIV test results at baseline should not be started on PrEP. They should be assessed for early HIV infection and treated according to local antiretroviral treatment guidelines (8). Such patients can only be started on PrEP if and when HIV infection is excluded.

^† The Therapeutic Goods Administration (TGA) has not approved this regimen in Australia.