Do Patients adherent on PrEP exposed to HIV have seroconversion symptoms & falsely reactive HIV tests? Mark Roche1, Elaney Youssef1, Yvonne Gilleece¹, Daniel Richardson¹,Amanda Clarke¹, Nicky Perry¹, Martin Fisher¹, Yolanda Collaco Moraes², Laura Else³, Sheena McCormack² 1.Brighton & Sussex University Hospitals Trust 2.MRC Clinical Trials Unit @ University College London 3.University of Liverpool Background Sensitivity & Specificity rates of Point of Care Tests Truvada is licensed for use as pre-exposure prophylaxis (PrEP) for the reduction of HIV in the US. In the UK, PrEP is only widely available via enrolment to the PROUD study for men who have sex with men (MSM). Participants are randomised to immediate daily Truvada for two years or deferred Truvada for the last year only. Name Ag / Ab Sensitivity (95% CI) Specificity (95% CI) Determine HIV - 1/2 Ag/Ab Combo 100% (Ag/Ab) (CI 99.7% - 100%) 99.6% (Ag) (CI 98.5 - 99.9%) 99.2% (Ab) (CI 95.7% - 99.8%) Clearview COMPLETE HIV-1/2 Ab 99.7% (98.9% - 100%) 99.9% (CI 99.6% - 100%) OraQuick Advance HIV-1/2 99.6% (98.5 - 99.9%) 100% (CI 99.7% - 100%) Case Patient M presented to his local GUM clinic reporting a significant increase in unprotected passive anal intercourse in the previous 6 months. He was enrolled in the PROUD study and was randomised to the immediate Truvada arm. At baseline he had a HIV negative POCT and serum test. At his 3 month PROUD visit he was unwell complaining of flu like symptoms and malaise for 5 weeks; rectal pain, bleeding and constipation for 2 weeks, and 8kg weight loss. He reported passive anal intercourse 8 weeks previously with several known HIV positive partners. An HIV POCT test was performed which was p24 Antigen and Antibody reactive (Determine HIV-1/2 Ag/Ab Combo). He also had rectal gonorrhoea. At this stage Patient M was advised to discontinue taking his Truvada immediately. The following day, a serum HIV test collected on the same day as POCT (Abbott Architect framework and confirmed by Biomerieux Vider) was negative. An HIV RNA (Abbott PCR) was <40 copies/ml. Samples taken on the same day as the reactive HIV POCT were analysed for Tenofovir and emtricitabine levels and although there were variations between plasma and serum levels, they were consistent with the patient’s report of 100% adherence. Tenofovir & Emtrcitabine Levels Drug TDF (ng/ml) FTC (ng/ml) Plasma Level 188.80 1602.78 Serum Level 116.64 1043.20 Title Conclusion Patient M may have been sufficiently exposed to HIV to have a positive DETERMINE but by being on PrEP prevented an established infection. The reactive DETERMINE was both Antigen and Antibody falsely reactive. Sensitivity of POCTs in HIV positive MSM is 96% compared to 98% for a 4th generation test (Delaney et al, 2011) Confirmatory HIV testing in MSM on PrEP is needed to inform decisions about continuing or discontinuing treatment Acknowledgments Many thanks to Patient M who gave his informed consent for this abstract. References: Clinical and Laboratory Standards Institute. Procedures and Devices for the Collection of Diagnostic Capillary Blood Specimens; Approved Standard-5th H4-A5 Vol.24 No.21 Delaney, P et al, (2011) Evaluation of the Performance Characteristics of 6 Rapid HIV Antibody tests; Journal of Clinical Infectious Diseases 52 (2): 257-263. http://www.proud.mrc.ac.uk email: PROUD@ctu.mrc.ac.uk