CE Exam
Comparison of 4th-Generation HIV Antigen/
Antibody Combination Assay With 3rd-Generation
HIV Antibody Assays for the Occurrence of FalsePositive and False-Negative Results
Adnan Alatoom
Lab Med Spring 2015;46:e28-e29
DOI: 10.1309/LM0SC05ATAFWZHDN
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Course ID: CEUDI41501
1. Which one of the following features differentiates
the fourth generation from third generation HIV serologic assays:
A. Fourth generation assays detect HIV IgM and IgG
antibodies while third generation assays detect IgG
antibodies only
B. Fourth generation assays detect HIV IgM and IgG
antibodies while third generation assays detect IgM
antibodies only
C. Fourth generation assays detect antibodies to HIV-1
and HIV-2 whereas third generation assays detect antibodies to HIV-1 only
D. Fourth generation assays detect both HIV antibody and
p24 antigen whereas third generation assays detect
HIV antibody only
3. A 29 year-old male intravenous drug user complains of fever, skin rash, and muscle aches. HIV
screening with the fourth generation assays is positive. Confirmation by western blot and immunofluorescence is negative whereas HIV-1 RNA viral load is
2,000,000 copies/ml. Which of the following explains
the patient’s laboratory findings?
A. The antibody confirmation assays are likely false negative because HIV patients should have HIV antibodies
B. The positive HIV-1 RNA is likely false positive because
the antibody confirmation assays are negative
C. The patient has an acute HIV infection and the screening test most likely detected HIV P24 antigen only
D. The patient has an advanced HIV disease with declining antibody level
2. Which one of the following statements regarding
HIV serological diagnostic tests is correct?
A. HIV fourth generation assays are more sensitive and
less specific than third generation assays
B. Detection of P24 antigen by fourth generation assays
makes them better assays than third generation assays in detecting acute HIV infection
C. The fourth generation assays detect group O HIV-1
better than third generation assays
D. The fourth generation assays can distinguish between
the detection of HIV-1 p24 antigen, HIV-1 antibody, or
HIV-2 antibody
4. Which one of the following facts regarding HIV
disease is correct?
A. Since HIV is a double-stranded DNA virus, DNA level
can be assessed in the blood
B. According To recent studies in the US, 1-5% of HIV
patients are unaware of their HIV infection
C. Acute HIV infection contributes significantly to HIV
transmission
D. The CDC has recently recommended HIV screening
in patients aged 13 to 64 years only if risk factors are
present
e28 Lab Medicine Spring 2015 | Volume 46, Number 2
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CE Exam
5. The window period is the time between HIV acquisition and the appearance of positive laboratory
results. Which of the following statements is correct
regarding the window period?
A. The window period is characterized by massive HIV
viral replication and undetectable antibodies
B. In the window period, P24 antigen can be detected
5-7 days before the appearance of HIV RNA
C. Because of high specificity, there are no possible false
positive results with the HIV fourth generation assays
during the window period
D. The sequence of tests that become positive after the
window period are HIV RNA detection, IgM antibodies,
IgG antibodies, P-24 Antigen, HIV Western blot tests
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Spring 2015 | Volume 46, Number 2 Lab Medicine e29