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Introduction

Diagnostic tests can be grouped into 3 categories.:
Direct detection - the clinical specimen is examined directly for the presence of virus particles, virus antigen or viral nucleic acids.
Indirect examination - virus isolation - the specimen into cell culture, eggs or animals in an attempt to grow the virus: this is called virus isolation.
Serology - A serological diagnosis can be made by the detection of rising titres of antibody between acute and convalescent stages of infection, or the detection of IgM. The majority of common viral infections can be diagnosed by serology.
The specimen is very important.
A positive result from the site of disease would be of much greater diagnostic significance than those from other sites. For example, in the case of herpes simplex encephalitis, a positive result from the CSF or the brain would be much greater significance than a positive result from an oral ulcer, since reactivation of oral herpes is common during times of stress.

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2. Indirect Examination
Cell Culture - cytopathic effect, haemadsorption, confirmation by neutralization, interference, immunofluorescence etc.
Eggs pocks on CAM - haemagglutination, inclusion bodies
Animals disease or death confirmation by neutralization

Detection of rising titres of antibody between acute and convalescent stages of infection, or the detection of IgM in primary infection.

2. Haemagglutination inhibition tests

3. Immunofluorescence techniques (IF)

4. Neutralization tests

5. Single Radial Haemolysis

1. Radioimmunoassay (RIA)

2. Enzyme linked immunosorbent assay (EIA)

3. Particle agglutination

4.Western Blot (WB)

5. Recombinant immunoblot assay (RIBA), line immunoassay (Liatek) etc. �