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Laboratory Diagnosis of HIV Infection

Assay-Defined HIV Detection Windows and Infection Periods

Slide 3

October 2009

Before I discuss further the various tests available commercially, let’s also look at the various detection windows and infection periods that are commonly indicated in the literature, because it has caused some confusion as to what are the definitions.

You can see from this timeline, indicated in the blue line and the various time points indicated by the down arrows, that there are basically 2 windows of HIV infection for detection. The first is the seroconversion window, which starts from time of infection, indicated by the first arrow on the left-hand side of the timeline, to the time point where antibody becomes detectable. So, this seroconversion window period actually includes the eclipse period and the acute infection period. The eclipse period is the period at which time that only molecular tests can detect the presence of HIV RNA. The acute infection is the period between viral infection detectable by molecular tests and a serologic response, which is detectable by serologic assays. Now the incidence window is the period from the time of antibody detection first from the infected individual until a specific time point where the serologic assay can determine recent infection. So that particular window period is also known as the recent infection. And, after this assay-specific detection point for recent infection, we see long-standing HIV infection. This timeline has been proposed by the World Health Organization Technical Working Group on HIV Incidence Assays.

Assay-Defined HIV


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