HIV diagnosis

1. HIV diagnosis

3. HIV diagnosis (general) • Serologic tests for HIV infection are based upon detection of IgG antibodies against HIV-1 antigens in serum

4. HIV diagnosis (general) • Yes but not only IgG

5. HIV diagnosis (general) • HIV-specific IgG antibodies appear 6 to 12 weeks following HIV infection in the majority of patients

6. HIV diagnosis (general) • Yes

7. HIV diagnosis (general) • HIV-specific IgG antibodies appear by six months in all HIV infected patients

8. HIV diagnosis (general) • HIV-specific IgG antibodies appear by six months in 95 percent of patients

9. HIV diagnosis (general) • Name 2 of the most specific tests to diagnose HIV

10. HIV diagnosis (general) • Viral culture • NAT (PCR)

11. HIV diagnosis (general) • Explain the difference between an HIV EIA test and an HIV ELISA test

12. HIV diagnosis (general) • EIA: conjugated HIV antigens on the plate  not “sandwich method”; 3rd and 4th generation are “sandwich methods”;

13. 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.

14. Immunoassays-10 • Yes

15. 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

16. Immunoassays-20 • Yes

17. Immunoassays - 30 • False negative HIV antibody tests have been reported among participants in HIV vaccine trials

18. Immunoassays - 30 • False: Positive HIV antibody tests have been reported among participants in HIV vaccine trials.

19. 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?

20. Immunoassays - 40 • At least second generation immunoassay and also NAT testing for HIV-2

21. Immunoassays - 50 • The patient with an indeterminate result with an HIV rapid test should have repeat testing in one to two months with • rapid serologies • Standard serologies • Rapid OR standard serologies

22. 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

23. NAT (PCR)- 10 • The major limitations of these assays include cost, the requirement for venipuncture, and time interval between sample collection and test results

24. NAT (PCR)- 10 • Correct

25. NAT (PCR)- 20 • The viral NAT should always be used to diagnose acute HIV infection

26. NAT (PCR)- 20 • Only if there is clinical suspicion

27. NAT (PCR)- 30 • Quantitative HIV RNA is the preferred test for staging and therapeutic monitoring

28. NAT (PCR)- 30 • Correct

29. 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

30. NAT (PCR)- 40 • B

31. 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

32. NAT (PCR)- 50 • D