Is a 90-day post-Exposure Prophylaxis (PEP) test necessary for confirming Human Immunodeficiency Virus (HIV) status after a negative 30-day test result using the Abbott Determine (4th generation test)?

From the Guidelines

A 90-day post-Exposure Prophylaxis (PEP) test is not necessary for confirming Human Immunodeficiency Virus (HIV) status after a negative 30-day test result using the Abbott Determine (4th generation test). When you complete a full course of PEP and test negative 30 days after finishing treatment, this result is considered definitive with a 4th-generation antibody test like the Abbott Determine, as HIV antibodies typically develop within 4-6 weeks after infection, so by the 30-day post-PEP mark, any infection would have produced detectable antibodies 1. The most recent and highest quality study recommends that HIV serostatus should be reassessed at 4 to 6 weeks, 3 months, and 6 months after exposure, but also notes that shorter follow-up (eg, 3 or 4 months) may be possible with a fourth-generation assay 1. There are no documented cases where someone tested negative at this timepoint and later converted to positive. While some healthcare providers might recommend a 90-day post-PEP test out of extra caution, this is not medically necessary based on available evidence. If taking an additional test at 90 days post-PEP would provide you with greater peace of mind, you can certainly do so, but your 30-day post-PEP negative result already confirms you do not have HIV and you can confidently consider this matter resolved.

Some key points to consider:

• The Abbott Determine is a 4th-generation test, which is more sensitive than earlier tests and can detect both HIV antibodies and p24 antigens 1.
• The Centers for Disease Control and Prevention recommend that postexposure prophylaxis regimens should be continued for 28 days, and HIV serostatus should be reassessed at 4 to 6 weeks, 3 months, and 6 months after exposure 1.
• The risk of delayed HIV seroconversion is extremely low, and the infrequency of this occurrence does not warrant adding to the anxiety level of the exposed persons by routinely extending the duration of postexposure follow-up 1.

It's worth noting that the guidelines for postexposure prophylaxis and follow-up testing are based on the best available evidence and are intended to minimize the risk of HIV transmission while also minimizing unnecessary testing and treatment 1. In summary, a 90-day post-PEP test is not necessary, and a negative 30-day test result can be considered conclusive.

From the Research

HIV Post-Exposure Prophylaxis (PEP) and Testing

• The provided studies do not directly address the necessity of a 90-day post-Exposure Prophylaxis (PEP) test for confirming Human Immunodeficiency Virus (HIV) status after a negative 30-day test result using the Abbott Determine (4th generation test) 2, 3, 4, 5, 6.
• However, the studies discuss the efficacy and tolerability of various PEP regimens, including tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC)/rilpivirine (RPV) and elvitegravir/cobicistat/TDF/FTC, in preventing HIV seroconversion 3, 6.
• The studies also highlight the importance of adherence to PEP regimens, with completion rates ranging from 39% to 92% depending on the regimen and dosing frequency 2, 3, 6.

PEP Regimens and Adherence

• A study evaluating the co-formulation elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (Stribild®) for HIV PEP found that 92% of participants completed the 28-day regimen, with only three switching to another PEP due to side effects 2.
• Another study assessing the tolerability and efficacy of TDF/FTC/RPV for PEP reported a completion rate of 86.1%, with no HIV seroconversions observed at week 16 3.
• The use of single-tablet regimens, such as elvitegravir/cobicistat/TDF/FTC, may optimize PEP adherence due to their simplicity and reduced pill burden 6.

HIV Testing and Diagnosis

• While the provided studies do not specifically address the timing of HIV testing after PEP, they emphasize the importance of monitoring for HIV seroconversion and adverse events during and after PEP 3, 6.
• The studies suggest that HIV testing should be performed at regular intervals, such as at week 16, to detect potential seroconversions 3.