The major drawback of these tests is that they are very expensive. However, when the costs come down, they should gain widespread acceptance in the virology laboratory. Looking further ahead, DNA chip technology may one day be used to detect viruses from clinical specimens. Besides detecting the presence of the virus, it may be able to tell the viral load, and to which antiviral agent that the virus is sensitive to at the same time. The virus in the clinical specimen is amplified by growing in tissue culture, eggs or animals.
Cell culture is by far the most commonly used method.
The obvious disadvantage of virus isolation is the length of time required for the CPE or the ability to haemadsorb to become apparent, which may take from a few days to a few weeks. Longer, if confirmatory tests such as virus neutralization are to be carried out. Another problem with virus culture is that the sensitivity is often low and depends on a large extent the quality of the clinical specimen received. Also, virus isolation would not be applicable to viruses which are difficult or cannot be cultivated such as hepatitis B and parvovirus. Serology Serology remains the bulk of the work carried out by a routine diagnostic virus laboratory.