Tests for diagnosis of viral infections

on 15.9.05 with 0 comments

Culture (gold standard) - examine for cytopathic effect (CPE) - takes a few days to two weeks

a. Can add red cells to check for hemagglutinins

b. 100% specificity (for showing a virus is there, not specific ID), poor sensitivity

c. Without antigen detection (shell vial technique) can only make presumptive ID of virus

2. Antigen detection - can do on cell specimens from patient or on culture (shell vial technique)

3. Immunofluorescence assay - Ab labeled w/ fluorescing compound - use UV microscope

4. ELISA, immunoperoxidase - Ab labeled w/ enzyme that changes substrate color

a. Serology for IgG (four-fold rise of two specimensis diagnostic), IgM - single result is diagnostic

b. DNA probes/PCR

c. Electron microscopy for ID of viral particles - expensive, insensitive

Category: Microbiology Notes



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