Screening for Asymptomatic Genital Herpes

Is Serologic Testing Worth It?

Leia Raphaelidis, FNP


Journal for Nurse Practitioners. 2014;10(3):194-199. 

In This Article

Confirmatory Testing

Although the diagnosis of asymptomatic genital herpes made via type-specific serology may be met with incredulity, the tests have a high degree of accuracy. For example, the HerpeSelect test by Focus Diagnostics, one of the most widely used technologies, has a sensitivity of 96% and a specificity of 97% for HSV-2.[24] The manufacturer has disclosed that most false positives are associated with test specimens that have values at the bottom of the reference range (index values between 1.1 and 3.5). Index values over 3.5 are highly unlikely to be false positives. Even test manufacturers recommend that additional testing be performed before accepting the diagnosis if the probability of a true positive is low.[25] It is known that the positive predictive value of the test is low in a low prevalence population. One study found it to be no higher than 37.5%.[26]

Given that the Web is loaded with message boards urging those diagnosed via serology to seek confirmatory testing, it should be expected that patients who have gone online to do more research may ask for it. One option for confirmatory testing would be to order a different type-specific test.[27] However, the best and most accurate option is to order an HSV Western blot. This test is only available via the University of Washington's Clinical Virology Laboratory (1–800–713–5198). Some Quest Diagnostics sites may be able to facilitate this testing. Otherwise, samples are mailed directly to the Virology Lab in Seattle for processing. The Western blot, with sensitivity and specificity of greater than 99%, is considered the definitive test for the diagnosis of herpes via serology.[28]