Understanding Herpes Testing: Why You Should Request an IgG Test
So you want to be screened for herpes. You have access to a healthcare professional who is willing to work with you/help you access said test. You don’t have any presenting symptoms, so you know that you need a blood test, but which one should you request?
Short answer? IgG.
Long answer? There’s always a possibility that your provider may not give you a choice in the matter. IgM tests are NOT the recommended screening method for herpes for a variety of reasons, some of which are listed here:
•can’t distinguish between HSV-1 or HSV-2
•may cross-react with other herpes family viruses
•although IgM usually signals a current or new infection, it can also appear in 1/3 of people during recurrences (ASHA, 2020).
Overall, IgM tests can lead to deceptive results. In conducting research for this post, I came across several medical blogs and institutions who made statements on their discontinuation of IgM testing for herpes (new to me!).
So let’s break down why IgG reigns supreme, but also what it lacks:
While IgG tests can detect whether antibodies are HSV-1 or HSV-2, it can’t tell someone the location of the infection (i.e. if someone has genital HSV-1, but has never had a symptom, the test will only be able to tell an individual that HSV-1 was detected—further complicating disclosure).
While IgG tests are more accurate, these antibodies take time to build up in someone’s system. As an example, someone could walk into a clinic with presenting symptoms and receive a positive culture result, but a negative IgG test (signaling a recent infection). It is recommended that individuals wait 12-16 weeks from the last date of exposure for the most accurate test results.
While IgG tests can fill in some of the blanks (if someone is positive for herpes and which type), these test results often lead many newly diagnosed individuals down the impossible rabbit hole of questions like: 1) When did I get it? 2) How did I get it? 3) Who did I get it from? 4) Did they know they had it?
Although herpes isn’t included in screening panels, I often wonder if some providers don’t offer/deny testing requests to avoid some of the above questions/panic.