Wk 4 HIV Labs and Diagnostics Flashcards
Who is considered for routine HIV screening?
Anyone ages 13-75
How often should someone considered high risk for contracting HIV be screened?
Yearly
Who is considered at high risk for contracting HIV? (5 groups)
1) Men who have sex with men
2) IV drug users
3) Persons who exchange sex for $/drugs
4) Sex partners of people who are infected with HIV, bisexual, or IV drug users
5) Persons who have sex with people who have unknown HIV status
What is required before doing an HIV screening?
Consent form that is voluntary and has had the chance to opt-out
What should you pay scrupulous attention to concerning HIV screening?
Confidentiality
What should you educate a patient on who is undergoing HIV screening?
Counseling to reduce the likelihood of exposure
What percentage of HIV-infected persons are aware of their status?
Only 85%
What is a concerning issue for HIV infected persons?
Adherence
What type of tests are the older generation HIV tests?
HIV antibody only
What are the fourth generation HIV tests?
Combination of antibody and antigen testing
What are 3 types of HIV older generation tests?
ELISA
HIV-1/HIV-2
Western Blot
What does the ELISA test stand for?
Enzyme linked immunosorbent assay
What is the Western Blot used for?
Confirmatory follow up testing
What is the advantage of the new generation HIV tests over the older generation HIV tests?
Because they test for both the antigen and antibodies, they can identify HIV infection earlier because antibodies have to be produced after the antigen replicates
What type of HIV test tests for the actual viral load level?
HIV RNA
What is the HIV-1/HIV-2 test?
Differentiation assay
Which test type has almost 100% specificity and sensitivity?
Combination, HIV antigen and antibody tests, 4th generation
What are the two categories of HIV RNA tests?
Qualitative and quantitative
What are qualitative HIV RNA tests used for?
Used as a screener to identify HIV-infected individuals
What is an example of a time where the qualitative HIV RNA test might be used?
Blood donors
What is a quantitative HIV RNA test used for?
It has the ability to count viral load, so it is used for management/monitor those who are infected or diagnose
How many days can the newer generation HIV test positive?
15-20 days
What are the 3 results a patient could get after doing an HIV test?
Positive
Negative
Indeterminate
What is the criteria for a patient to be HIV-positive?
Positive ELISA or combination assay followed by a positive confirmatory assay
What is the criteria for a patient testing negative for HIV?
A negative screening ELISA or combination assay, do not need a follow up test
What is the criteria for a patient testing indeterminate for HIV?
The first test is positive, but the follow up test is indeterminate or negative
What is the window period, concerning HIV?
Time between potential exposure to HIV infection and the point when the test will give an accurate results
During the HIV window period a patient is…
VERY infectious, but will still test negative
What is the eclipse phase of HIV infection?
Point of exposure to point of increased viral load
What is the window period phase of HIV infection?
Point of exposure to point of detectable antibodies
When is the patient infectious during the phases of HIV infection?
They become infectious after the eclipse phase, with high viral load
How long does it take to develop antibodies after being exposed to HIV?
Usually within 4 weeks, but almost all patients by week 12
How is the progression of HIV monitored? (2 things to test for)
CD4 count
Viral load
What number do you want the CD4 count to be?
Greater than 500
What number do you want the viral load to be?
Less than 50 or non-detectable
What is the best indicator for a healthy immune system?
CD4 count
What is the normal CD4 cell count range?
800-1200
CD4 count helps monitor the progression of __
AIDS
CD4 count helps determine when it’s time for…
Prophylactic treatment and risk for opportunistic infections
What is are the CD4 cells also called?
Copies
What CD4 count is the HIV infected person vulnerable to opportunistic infections/rare cancers?
< 200
How often is the CD4 count check in an HIV positive patient?
Every 3-4 months
What is the best indicator of how active HIV is in a patient’s body?
Viral load testing
If an HIV infected person remains untreated, the virus produces…
billions of new viral copies per day
What is viral load?
Plasma HIV RNA
What is plasma HIV RNA?
The viral load
What does the viral load quantify?
Viral burden in plasma
How often is viral load testing done in an HIV positive patient?
Every 3-4 months
What else does the viral load test help monitor?
A patient’s response to ART
The lowest level of detection __ with each test
differs
What is the goal for viral load with HIV positive patients?
Keep it at an undetectable level
How long is the clinical latency period of HIV?
Years
What does undetectable viral load NOT mean?
It does not indicate absence or clearance of the virus from the body
What is the recommendation for viral load testing?
Check twice at baseline before starting ART, and then every 3-4 months
What are other labs worth monitoring in a patient with HIV? (5 tests)
WBC Platelets H&H LFTs Resistance to ART drugs
What two WBCs are especially important for monitoring HIV?
Lymphocytes and neutrophils
What type of cell is a CD4 cell?
Lymphocyte
Why are LFTs monitored for HIV patients?
Early detection of HCV or HBV confection is very important
