Window periods

Different authorities give slightly different estimates for the duration of the window period between exposure and the ability of tests to detect infection:

  • nine days1 
  • nine to 14 days2
  • twelve days3 

HIV RNA is the first marker of infection that appears after infection (approximately five days before p24 antigen), and so these tests may be able to detect primary infection before a fourth-generation test. However, their sensitivity at this point has not been extensively studied.

Related Links

References

  1. Branson BM State of the art for diagnosis of HIV infection. Clin Infect Dis 45:S221-225, 2007
  2. Coombs RW Clinical laboratory diagnosis of HIV-1 and use of viral RNA to monitor infection. In Holmes KK (editor), Sexually Transmitted Diseases. New York: McGraw-Hill, 2008
  3. Maldarelli F Diagnosis of Human Immunodeficiency Virus infection. In Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases (sixth edition). Philadelphia: Elsevier Churchill Livingstone, 2004