hiv diagnosis (general) immunoassaysnat (pcr) 10 20 30 40 50
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HIV diagnosis (general) Immunoassays NAT (PCR)
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HIV diagnosis (general)
• Serologic tests for HIV infection are based upon detection of IgG antibodies against HIV-1 antigens in serum
HIV diagnosis (general)
• Yes but not only IgG
HIV diagnosis (general)
• HIV-specific IgG antibodies appear 6 to 12 weeks following HIV infection in the majority of patients
HIV diagnosis (general)
• Yes
HIV diagnosis (general)
• HIV-specific IgG antibodies appear by six months in all HIV infected patients
HIV diagnosis (general)
• HIV-specific IgG antibodies appear by six months in 95 percent of patients
HIV diagnosis (general)
• Name 2 of the most specific tests to diagnose HIV
HIV diagnosis (general)
• Viral culture• NAT (PCR)
HIV diagnosis (general)
• Explain the difference between an HIV EIA test and an HIV ELISA test
HIV diagnosis (general)
• EIA: conjugated HIV antigens on the plate not “sandwich method”; 3rd and 4th generation are “sandwich methods”;
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• The standard screening assay for detecting antibodies to HIV is an enzyme immunoassay (EIA). A confirmatory Western blot is performed if the screening test is positive to exclude a false positive test.
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• Yes
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• The most common cause of a false negative HIV antibody test in a high-risk patient is that the assay is being conducted during the "window period" of acute HIV infection prior to seroconversion
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• Yes
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• False negative HIV antibody tests have been reported among participants in HIV vaccine trials
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• False: Positive HIV antibody tests have been reported among participants in HIV vaccine trials.
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• An AA patient from Cameroon presents with acute febrile illness, skin rash and lymphadenopathy 3 weeks after a high risk exposure. What tests should you order?
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• At least second generation immunoassay and also NAT testing for HIV-2
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• The patient with an indeterminate result with an HIV rapid test should have repeat testing in one to two months with
a)rapid serologiesb)Standard serologiesc) Rapid OR standard serologies
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• C: The patient with an indeterminate result should have repeat testing in one to two months with rapid or standard serologies PLUS viral NAT
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• The major limitations of these assays include cost, the requirement for venipuncture, and time interval between sample collection and test results
NAT (PCR)- 10
• Correct
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• The viral NAT should always be used to diagnose acute HIV infection
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• Only if there is clinical suspicion
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• Quantitative HIV RNA is the preferred test for staging and therapeutic monitoring
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• Correct
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• A HIV-infected mother on ART delivers a baby. Which test will best rule out HIV infection in the baby?
• A) RNA qual PCR• B) DNA PCR• C) 4th generation immunoassays• D) Neither of the above. The baby will need
long term follow up with serial tests
NAT (PCR)- 40
• B
NAT (PCR)- 50• An AA patient from Cameroon presents with acute
febrile illness, skin rash and lymphadenopathy 3 weeks after a high risk exposure. What tests should you order?
• a) 4th or 3rd generation immunoassay• b) a + standard HIV PCR available in the clinical lab• C) a+ contact reference lab for appropriate PCR
testing • D) None of the standard tests will rule out
completely the possibility of HIV infection
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• D