HIV Labs & Diagnostics Flashcards
Which groups of people are recommended for annual HIV screening?
- MSM
- Injection Drug Users
- Persons exchanging sex for drugs/money
- Sex partners: HIV+, bisexual, injection drug users, or status of partner unknown
What are the Antibody-ONLY HIV tests?
- ELISAs- Enzyme-linked immunosorbent assays
- HIV-1/HIV-2 differentiation assays
- Western Blot– confirmatory follow-up testing
The 4th gen HIV antibody/antigen test can detect HIV infection in as little as _____ days.
15-20
The HIV RNA test can be used to count/quantify ______.
Viral Load
Which type of test is used to detect the presence of HIV in donated blood?
RNA (qualitative test)
Criteria for HIV+ test results?
A positive ELISA or combination assay —- followed by a confirmatory test (two positive results)
How are the results interpreted if a Pt has a positive Antibody/Antigen test, followed by a negative confirmatory test?
Indeterminate
T/F A person who received negative HIV test results can still be infected?
True (Window period in testing)
Can someone who tests HIV- still transmit the virus to another person?
Yes, If they are in the window period after infection and haven’t had time to develop antibodies (assuming an antibody test was administered).
Most patients develop antibodies by which week of infection?
4
What are two basic lab values we want to know about an HIV patient?
CD4 Count and Viral Load
What does CD4 count indicate about the patient?
The health of their immune system/disease progression
Whats the normal range of CD4 cells?
800-1200 cells/μL of blood
What two considerations can determine an HIV infection has progressed to AIDS?
CD4 Count <200 cells/μL of blood; Opportunistic infection
What does viral load indicate?
How active HIV is in patient’s body (Meds working?)
T/F Once a patient is determined to have an undetectable viral load their meds can be withheld?
False (Infection will return if ART therapy is discontinued)
About how often should follow-up labs be drawn for an HIV+ patient?
Every 3-4 months unless otherwise indicated
What other lab values could be useful to know about HIV+ patients?
- WBC (esp. lymphocytes/neutrophils)
- Platelets
- H&H
- LFTs (Liver function tests)
- ART drug resistance tests
What are some takeaways from the CDC estimates about HIV (regarding awareness of infection and access/adherence to treatment?
Many HIV+ individuals are unaware they are positive, adherence to ART is low (viral load unsuppressed)
4 implications/considerations to HIV Screening
- Consent to testing (opt-out documentation)
- Confidentiality of testing/results
- Counseling available
- Referrals to care if positive
