Advanced Techniques in Diagnostic Microbiology

TABLE 3.2 (Continued)
Pathogen Methods Specimen Sensitivity Specificity Comments
Human immunodeficiency
virus
Human immunodeficiency
virus
Hepatitis B surface
antigen (HBsAg)
and e antigen
(HBeAg)
EIA Blood 50–99% 95–99% Once antibody appears in blood, sensitivity of antigen
detection decreases. Immune complex dissociation
and signal amplification boost sensitivity. Rheumatoid
factor can cause false-positive results. Neutralization
test needed to confirm specificity of result.
Real-time
immuno-PCR
Blood 99% Free HBsAg is produced in 100- to 1000-fold excess
over complete virus particles. Thus HBsAg is
generally more sensitive than DNA techniques.
HBeAg has been the standard marker for high levels
of viral replication.
POC, point of care; ELISA, enzyme linked immunosorbent assay; EIA, enzyme immunoassay; IF, immunofluorescence; PCR; polymerase chain reaction.
Other rapid formats: IA, immunoassay; IC, immunochromatography; OIA, optical immunoassay; EVEA, endogenous viral encoded enzyme assay. LA, latex agglutination;
NP, nasopharyngeal; BAL, bronchoalveolar lavage; EM, electron microscopy.
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