To provide some clarification, since so many of you write to me asking about herpes testing, here's a run down of the current available tests. They each have limitations, though I indicate which are the most specific. A doctor will quite often take your history/examine you and then "marry the history/exam findings to the test results" which can mean that even in the face of a negative test result, your medical history and examination might indicate presence of herpes. It's important to realize that false-positives can also occur during testing.
1- Clinical examination - since HSV can present without lesions or the lesions can be confused with other diseases, just diagnosis by examination is not a perfect option.
2- Viral culture requires that lesions be present so the fluid can be taken from the sores and tested. It can be wrong 50% of the time but it is still a viable test because it can differentiate between HSV1 and HSV2.
3- PCR also requires the presence of active viral shedding from lesions. It is considered better than viral culture and is also specific for type 1 and 2 HSV.
4- ELISA and non-specific blood tests - which may only be helpful in someone who can state without doubt that they never had herpes exposure and now suspects that they have had an exposure. Since herpes can present without physical symptoms, it is rare that a person will present this way so this test is problematic. It also cannot distinguish between HSV1 and HSV2.
5- Western Blot and Focus Technologies HerpeSelect - Active viral shedding not necessary. Tests for type 1 and type 2. Only the University of Washington processes Western blot so you typically have to wait a week to 10 days for results.
6- IgG tests for non specific presence of herpes while IgM tests for recent (within 3-4 months only) exposure. A negative IgG with a positive IgM can be an excellent way to diagnose recent exposure to herpes.
Your doctor may have access to other tests but it's important to ask him about specificity, reliability and ability to identify HSV1 and HSV2.
Published On: December 29, 2008