Antibody tests: progress and pitfalls.
BACKGROUND
Serological tests are the basis for most laboratory virological diagnosis. The recent development of DNA amplification methods, allowing the detection of viral nucleotide sequences in clinical specimens, raises the question of whether or not these will supersede antibody tests.


OBJECTIVE
To assess the current strengths and weaknesses of current viral serology in the light of this new diagnostic approach.


METHODS
Review of relevant literature and consideration of experience in a national reference laboratory.


RESULTS
Due to technical advances, the intervals between exposure and seroconversion have decreased and tests for the specificity of antibody screening assays have improved. Also, viral antibodies can now be detected in saliva and urine. For epidemiological purposes sera can be tested cheaply and accurately in small pools. In some cases infecting viruses can be subtyped according to the antibody response. On the negative side, increased sensitivity has made tests prone to cross-contamination effects and, in some circumstances, serological responses are delayed or absent.


CONCLUSIONS
Viral diagnosis using antibody tests is highly cost-effective. Because they are versatile, relatively accurate and cheap, these tests will remain the backbone of routine laboratory diagnosis for some time to come.
Mortimer
P P
PP
Hepatitis and Retrovirus Laboratory, Virus Reference Division, Central Public Health Laboratory, 61 Colindale Avenue, London NW9 5HT, UK.