Table 10.1.

Advantages and Disadvantages of Various Diagnostic Methods

Diagnostic Method	Advantages	Disadvantages/Problems
Virus isolation	Produces further material for study of agent	Slow, time-consuming, can be difficult and expensive
	Usually highly sensitive	Selection of cell type, etc., may be critical
	“Open-minded”	Useless for non-viable virus or for non-cultivable agents
Direct observation by electron microscopy	Rapid	Relatively insensitive
	Detects viruses that cannot be grown in culture	Cumbersome for large numbers of samples
	Detects non-viable virus	Limited to a few infections
	“Open-minded”
Serological identification of virus or antigen, for example, EIA	Rapid and sensitive	Not applicable to all viruses
	Provides information on serotypes	Interpretation may be difficult
	Readily available, often as diagnostic kits	Not as sensitive as PCR
		Targeted to a specific agent
Detection of viral genomes by PCR	Rapid, very sensitive	High sensitivity may lead to detection of non-relevant co-infections
	Potentially applicable to all viruses incl. non-cultivable	Risk of DNA contamination
	Reagents (primers) for additional viruses easily made	Needs good quality control
	Good quantitation of load	Targeted to a specific agent
	Can be multiplexed
Antibody seroconversion (acute and convalescent sera)	Useful if appropriate samples for direct detection cannot be obtained, or to exclude a particular infection retrospectively	Slow, late (retrospective)
		Interpretation may be difficult
		Targeted to a specific agent
IgM serology	Rapid	False positives may occur
		Targeted to a specific agent