HIV Lab Testing Flashcards
(32 cards)
What form of HIV is most common throughout the world and progresses faster?
HIV-1. Both produce same patterns of illness.
Primary target cells for HIV
CD4 T lymphocytes
When will you see detectable levels of HIV antibody
3-8 weeks after infection- time between in “window period”. Serologic tests will be negative in window period.
The current, CDC standard serologic testing protocol to confirm HIV status is to perform:
screening EIA testing, if positive perform confirmatory Western Blot testing
HIV is able to infect cells containing:
CD4 protein receptor- Ex: T lymphocytes, macrophages, peripheral blood monocytes, B lymphocytes.
Per established criteria, ART treatment failure includes what patient response(s):
viral load remains above detectable levels
Laboratory tests most often used to routinely monitor an HIV positive patient include:
CD4 lymphocyte count and HIV RNA quantitation (viral load)
What is NOT a routinely encountered HIV opportunistic infection?
Cryptosporidium sp. causing pneumonia
What testing methodologies is NOT routinely utilized in the laboratory diagnosis of viral infections?
Electron microscopy
CD4 counts below what is usually when the patient becomes symptomatic, develops opportunistic pattern?
500
What classifies AIDS infection
CD4 <200 or AIDS defining condition
Standard serology Patient >2 years of age.
Enzyme immunoassay that will detect antibodies in patient serum. If 2 of 3 screen EIA tests are positive, confirmatory testing automatically performed.
What specific bands on a Western Blot do you look for for confirmation of HIV?
p24 and p120/160
T/F: If screen + and confirmatory negative, the patient is considered positive for HIV
False- Recommend follow up testing in 4 weeks
What can cause a false negative HIV test
- Window Period (usually all positive w/i 6 months.
- Seroreversion
- Atypical host response
- Agammaglobulinemia
- HIV-2 infection
- Technical or clerical error
False positive HIV results
- Autoantibodies
- HIV vaccines
- Technical or clerical error
Perinatal HIV infection in Infants. Testing:
Nucleic acid testing (NAT).
-Cant utilize serology as mother’s IgG HIV antibody will cross placenta. Infant positive if NAT positive 2 different times.
Virologic failure is classified as viral load above what?
200
Pneumo jiroveci is what type of organism? Detection how? When to start therapy? Drug of choice?
- Fungal
- Detection via stains of BAL, lung tissue
- CD4<200
- SXT
MAC: Detection how? Treatment when? With what?
Detection via culture.
-CD4 100) with Azithromycin
Cryptosporidium sp is a ________ that causes diarrhea and detection is ______ via microscopy or antigen detection.
Parasite- stool
Mycobacterium TB: Start therapy when with what?
TST> 5mm with Isoniazid
What parasite associated with HIV causes encephalitis, brain abscess and it detected via serology, staining tissue or NAT
Toxoplasma gondii
Microscopic detection of virus-induced cytopathic effects on cells in specimen is called what?
Cytology
