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”;

Immunoassays-10

• 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.

Immunoassays-10

• Yes

Immunoassays-20

• 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

Immunoassays-20

• Yes

Immunoassays - 30

• False negative HIV antibody tests have been reported among participants in HIV vaccine trials

Immunoassays - 30

• False: Positive HIV antibody tests have been reported among participants in HIV vaccine trials.

Immunoassays - 40

• 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?

Immunoassays - 40

• At least second generation immunoassay and also NAT testing for HIV-2

Immunoassays - 50

• 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

Immunoassays - 50

• C: The patient with an indeterminate result should have repeat testing in one to two months with rapid or standard serologies PLUS viral NAT

NAT (PCR)- 10

• 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

NAT (PCR)- 20

• The viral NAT should always be used to diagnose acute HIV infection

NAT (PCR)- 20

• Only if there is clinical suspicion

NAT (PCR)- 30

• Quantitative HIV RNA is the preferred test for staging and therapeutic monitoring

NAT (PCR)- 30

• Correct

NAT (PCR)- 40

• 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

NAT (PCR)- 50

• D