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Acute HIV Diagnosis — SCE Infectious Diseases MCQ

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EasyHIV MedicineAcute HIV DiagnosisSCE Infectious Diseases

A 28-year-old man presents with fever, sore throat, lymphadenopathy, and diarrhoea 2 weeks after unprotected sexual intercourse. A 4th generation HIV Ag/Ab test is negative. His clinician suspects acute HIV seroconversion. What is the most appropriate next investigation?

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Correct answer: A — HIV RNA viral load (PCR) — to detect viraemia during the antibody-negative window period

During acute HIV seroconversion, there is a window period where antibodies have not yet developed. While 4th generation tests detect p24 antigen (reducing the window to approximately 2 weeks), very early presentations may still be missed. HIV RNA PCR (viral load) can detect viraemia approximately 10 days post-infection, before p24 antigen or antibodies appear. If clinical suspicion is high despite negative 4th generation test, HIV RNA should be sent. A repeat 4th generation test should also be performed at 4 weeks.

Reference: BHIVA 2020 – HIV testing guidelines; NICE NG60 2016 – HIV testing