SIGNIFICANCE AND YIELD OF SEROLOGICAL TESTS: ARE WE RELYING TOO MUCH

Despite the great progress made in preventionand treatment, infectious diseases endure to affectthe humankind. While traditional pathogen-detectiontechniques, like culture, have proven their credibilityover time, they are often slow and sometimes insensitive.Immunoassay methods have been used for manydecades in the detection of antigen from infectiousagents and immune response; newer methods haveincreased the speed of detection. However, serologicallaboratory diagnosis of infectious diseasesis perpetrated with numerous types of elementaryglitches. The main basis of the serological tests isto detect the immune response of the patient to theprobable infectious agent. Hence, it neither detectthe disease directly nor the cause of the disease.The immune response varies from person to personand it may hamper the diagnostic accuracy of theserological tests, because immune system in eachperson is unique and polyclonal. The response variesamong individuals because of the variability of thegenetic background; as a result the measurabilityof antibodies made in response can be forecasted.Moreover, antigenic variants leading to diverse serotypesalso play an important role. Therefore, all thesebasic problems challenge a diagnostician in order toselect appropriate investigations for diagnosis, theirinterpretation and in standardizing serological tests.Hence, it might lead to wrong decisions and theultimate sufferer will be the patient. There has beenan increase in awareness among the clinical andreference laboratories as well as among the companiesof commercial test kits. Keeping in the view theproblems, it prompted the U.S. National Committeefor Clinical Laboratory Standards (NCCLS) to createspecific guidelines that address ”the generic problemsof preparation and characterization of antigensand antibodies, testing using these reagents, andunderstanding the results.” These approved guidelineswere made public in December 1994.