HIV tests during the window period

HIV tests during the window period

British Association for Sexual Health and HIV (BASHH)/ /Expert Advisory Group on AIDS (EAGA) statement on HIV window period:

• accredited diagnostic laboratories in the UK use "fourth generation " tests for HIV. These test for HIV antibodies and p24 antigen simultaneously in venous samples, and will detect the great majority of individuals who have been infected with HIV at 4 weeks after exposure
  
  
• patients attending for HIV testing who identify a specific risk occurring less than 4 weeks previously should not be made to wait before HIV testing as doing so may miss an opportunity to diagnose HIV (in particular acute HIV infection during which a person is highly infectious). They should be offered a laboratory "fourth generation " HIV test on a venous sample and be advised to repeat it when 4 weeks have elapsed from the time of the last exposure
  
  
• a negative result on a fourth generation test performed at 4 weeks post-exposure is highly likely to exclude HIV infection. A further test at 8 weeks need only be considered following an event assessed as carrying a high risk of infection
  
  
• patients at ongoing risk of HIV infection should be advised to retest at regular intervals
  
  
• patients should be advised to have tests for other sexually transmitted infections in line with advice on window periods for those infections (1)

Reference:

1. The Medical Foundation for AIDS & Sexual Health (MedFASH) 2016. HIV in primary care. A practical guide for primary healthcare professionals in Europe.