Herpes (HSV-1) IgM Test - Herpes Simplex Virus Type 1 (HSV-1) IgM Test

This serological test measures the titer of immunoglobulin M (IgM) antibodies directed against herpes simplex virus type 1 (HSV-1). These antibodies appear during the first to second week after the initial infection, peak, and then begin to decline over several weeks to months. The presence of HSV-1 IgM is indicative of a recent primary infection or viral reactivation, although reactivation may not always produce detectable levels of IgM. It is often ordered in conjunction with HSV-1 IgG testing to determine the stage of infection.