HIV Testing Flashcards
Understand different HIV tests
What is a fourth generation HIV test?
combines anti HIV and p24 antigen (reduces window period)
What is the false positive rate of EIA tests?
2% (hence need for confirmatory western blot)
What is a positive Western Blot?
reactivity to gp 120/160 + gp41 and p24
what is the longest time it takes to seroconvert for HIV
usually within 3 weeks but up to 6 months
how do you deal with indeterminate WB ?
risk assessment and viral load
What techniques are there to detect viral load
HIV-1 DNA PCR,RNA, bDNA (branched DNA) or RT-PCR
What is an appropriate response to antiviral therapy?
Decrease in 1 log after 4 weeks
Virologic suppression?
A confirmed HIV RNA level below the limit of assay detection (e.g., <48
copies/mL).
What is virologic failure?
The inability to achieve or maintain suppression of viral replication (to an HIV RNA level
<200 copies/mL)
Incomplete virologic response?
Two consecutive plasma HIV RNA levels >200 copies/mL after 24 weeks on an ARV regimen. Baseline HIV RNA may affect the time course of response, and some regimens will take
longer than others to suppress HIV RNA levels
What is virologic rebound?
Confirmed detectable HIV RNA (to >200 copies/mL) after virologic suppression.
What is persistent low level viremia?
Confirmed detectable HIV RNA levels that are <1,000 copies/mL.
What is virologic blip?
After virologic suppression, an isolated detectable HIV RNA level that is followed by a
return to virologic suppression.
What is considered to be significant change in CD4 count?
30% of absolute count or CD4% of 3%.
How long does it take CD4 count to rise after ART?
50 cells every 4-8 weeks after virologic suppression
