CHAPTER 24: Laboratory Diagnosis of HIV Infection Flashcards
All of the following describe HIV except
a. it possesses an outer envelope.
b. it contains an inner core with p24 antigen.
c. it contains DNA as its nucleic acid.
d. it is a member of the retrovirus family.
c. it contains DNA as its nucleic acid.
HIV virions bind to host T cells through which receptors?
a. CD4 and CD8
b. CD4 and the IL-2 receptor
c. CD4 and CCR5
d. CD8 and CCR2
c. CD4 and CCR5
Antibodies to which of the following viral antigens are usually the first to be detected in HIV infection?
a. gp120
b. gp160
c. gp41
d. p24
d. p24
Which of the following is typical of the latent stage of HIV infection?
a. Proviral DNA is attached to cellular DNA.
b. Large numbers of viral particles are synthesized.
c. A large amount of viral RNA is synthesized.
d. Viral particles with no envelope are produced.
a. Proviral DNA is attached to cellular DNA.
The decrease in T-cell numbers in HIV-infected individuals is caused by
a. lysis of host T cells by replicating virus.
b. fusion of the T cells to form syncytia.
c. killing of the T cells by HIV-specific cytotoxic T cells.
d. all of the above.
d. all of the above.
The most common means of HIV transmission worldwide is through
a. blood transfusions.
b. intimate sexual contact.
c. sharing of needles in intravenous drug use.
d. transplacental passage of the virus.
b. intimate sexual contact.
The drug zidovudine is an example of a
a. nucleoside analogue reverse-transcriptase inhibitor.
b. nonnucleoside reverse-transcriptase inhibitor.
c. protease inhibitor.
d. fusion inhibitor.
a. nucleoside analogue reverse-transcriptase inhibitor.
False-negative test results in a laboratory test for HIV antibody may occur because of
a. heat inactivation of the serum before testing.
b. collection of the test sample before seroconversion.
c. interference by autoantibodies.
d. recent exposure to certain vaccines.
b. collection of the test sample before seroconversion.
Which of the following combinations of bands would represent a positive Western blot for HIV antibody?
a. p24 and p55
b. p24 and p31
c. gp41 and gp120
d. p31 and p55
c. gp41 and gp120
The fourth-generation ELISA tests for HIV detect
a. HIV-1 and HIV-2 antigens.
b. HIV-1 and HIV-2 antibodies.
c. p24 antigen.
d. HIV-1 antibodies, HIV-2 antibodies, and p24 antigen.
d. HIV-1 antibodies, HIV-2 antibodies, and p24 antigen.
The conjugate used in the fourth-generation ELISA tests for HIV consists of enzyme-labeled
a. anti-human immunoglobulin.
b. HIV-1- and HIV-2-specific antibodies.
c. HIV-1- and HIV-2-specific antigens.
d. HIV-1- and HIV-2-specific antigens plus antibody to p24.
d. HIV-1- and HIV-2-specific antigens plus antibody to p24.
The characteristic laboratory finding in HIV infection is
a. decreased numbers of CD4 T cells.
b. decreased numbers of CD8 T cells.
c. decreased numbers of CD20 B cells.
d. decreased immunoglobulins.
a. decreased numbers of CD4 T cells.
Which of the following tests is currently recommended by the CDC to confirm a positive screening test result for HIV infection?
a. Rapid test for HIV-1 and HIV-2 antibodies
b. Western blot
c. Molecular testing for HIV RNA
d. HIV viral culture
a. Rapid test for HIV-1 and HIV-2 antibodies
Which of the following tests would give the least reliable results in a 2-month-old infant?
a. CD4 T-cell count
b. ELISA for HIV antibody
c. PCR for HIV proviral DNA
d. p24 antigen
b. ELISA for HIV antibody
Which of the following measurements are routinely used to monitor patients with HIV infection who are undergoing antiretroviral therapy?
a. HIV antibody titer
b. p24 antigen levels
c. CD4 T-cell and CD8 T-cell counts
d. CD4 T-cell count and HIV RNA copy number
d. CD4 T-cell count and HIV RNA copy number
