There are currently five ways to diagnose herpes. It is unlikely that your doctor will know about all of them. Thus, it will be to your advantage to print out this page and take it to your physician’s office when you go for testing. In addition to identifying whether an individual is infected with herpes, a test ideally should also provide 2 other pieces of information: 1) location and 2) the type of herpes simplex (HSV-1 or HSV-2). Type and location are important for assessing transmission risks (e.g., partners with the same type of HSV are unlikely to contract the same type again [regardless of locale]. However, they have a good chance of contracting a new type of simplex).

1. CLINICAL EXAMINATION and an assessment of your previous symptoms (history) are very poor at detecting herpes. HSV symptoms are easily confused with other diseases (even by experts) or may present atypically (redness rather than sores), so it’s quite possible to get an incorrect diagnosis on this basis alone.

2. VIRAL CULTURE - Although this test has a high rate of false negatives (~50%), it is the most valid test available. Unlike blood tests, it requires the presence of active viral shedding (e.g., open sores). This test can distinguish between HSV-1 and HSV-2 and has the advantage of being able to identify the location of infection. If you get this test, be sure that your doctor requests that the culture be typed (e.g., HSV-1) – most labs will not report type unless specified.

3. POLYMERASE CHAIN REACTION (PCR) - PCR testing also requires the presence of active viral shedding. However, PCR is a more sensitive test than viral isolation and is also type specific. PCR is now available for commercial use but it may not be available at your doctor’s facility.

4. NON-TYPE SPECIFIC BLOOD TEST - Certain types of blood tests, like the older ELISA, will detect herpes, but it can’t distinguish between the two types of herpes simplex (HSV-1 & HSV-2). HSV-2 is the type usually associated with genital HSV infection, while HSV-1 is the type usually associated with oral HSV infection (i.e., cold sores). However, both types of HSV can infect either location. Non-type-specific ELISAs may be useful if patients have no history of HSV infection. However, because a significant proportion of the population is infected with HSV-1 (~70%), non-type-specific tests are usually inconclusive at determining secondary HSV infections (e.g., HSV-2) due to the amount of cross reactivity.

5. TYPE-SPECIFIC BLOOD TESTS - such as the Western Blot, *Focus Technologies HerpeSelect (herpesonline.org recommended) ELISA or Immunoblot test for both HSV-1 and HSV-2 and can distinguish between the two types of HSV. Active viral shedding is not necessary (unlike PCR or Viral Isolation) in order to detect HSV infection (even if you are not currently having symptoms). There is only one U.S. lab that processes blood samples for the Western Blot (University of Washington) so you may have to wait a week or more for your results (For Canadians, the WB can be processed at lab Virdae Clinic).

NOTE: Blood tests for the long-term IgG antibodies are generally reliable only after 12 to 16 weeks of infection. Please be aware that all blood tests have an error rate and that false negative indications are possible, while false positive indications are almost nonexistent. Within the first few weeks of infection, detection of early antibodies (IgM) may potentially be useful for diagnostic purposes (absence of IgG, but presence of IgM may indicate a new infection). IgM testing is limited in value because, at this time, it is not type specific.