HSV 1 IgM Antibodies

A positive HSV IgM blood test indicates that herpes immunoglobulin M is present. This means that you are carrying the herpes virus. A false positive is possible.

Herpes IgM levels tend to go up early in an infection, and levels often go down with time. This means a positive herpes IgM result is most often associated with a new infection. However, individuals with recurrent herpes infections may also have positive herpes IgM blood results.

Does a positive HSV IgM test mean a herpes infection is new?

It may. However, if HSV IgM and HSV IgG are both positive, it indicates that the herpes virus has been present for at least several months.

Is it a new or recurring infection?

A positive IgM test might mean you have a new or recurrent HSV infection. If you have a positive IgM test and a negative IgG test, you likely have a new infection.

If an individual has positive results on both IgG and IgM tests, they may be having a recurrent herpes episode, instead of a new infection. A positive IgM test alone is more likely to be a new infection.

Individuals may not have a positive immunoglobulin G (IgG) test, an antibody test that detects IgG, until they've been infected for at least several months. However, IgG levels tend to remain high throughout the course of an infection, while IgM levels are more variable.

A herpes IgM (immunoglobulin M) test is a blood test that can detect early herpes simplex virus (HSV) infection. Herpes IgM is one of the first types of antibody that appears after infection, so this blood test is the earliest one that can be used to detect herpes.

HSV is a contagious condition that causes sores around the mouth or genitals.

The IgM test does not detect herpes directly. Instead, it looks for IgM, a type of antibody. This is a protein produced by the immune system in response to a herpes infection.

The herpes IgM antibodies can take up to 10 days to develop after a primary infection with the virus.