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Clarification For The Window Period of HIV



I am a bit confused. I have read from the CDC that the window period is three months. HIV in site says it's three months too. World Health organization says it's 21 days from the time of probable infection. Harvard School of Medicine says that it's three weeks. I am trying to read the reputable internet sites as some sites can be really confusing, especially if the person researching and reading is as anxious and paranoid as I am. Can you help clarify this issue please?


Acute HIV infection describes roughly the first 3 weeks following infection. At the peak of acute HIV infection, persons can be 1,000 times more likely to transmit HIV infection than those who have been infected 6 months or longer. Because HIV antibody tests only become detectable 4-6 weeks into the infection, accurate diagnosis requires the use of HIV viral load testing, which can detect the virus as early as 5 days after infection. The window period is the time delay from infection to a positive antibody test. Hope this helps. 

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Response by:

Pamposh   Kaul, MD Pamposh Kaul, MD
Assistant Professor
College of Medicine
University of Cincinnati