HERPES SIMPLEX VIRUS 1 IGM, SERUM

Herpes Simplex Virus 1 (HSV-1) IgM, Serum

What it is

The Herpes Simplex Virus 1 (HSV-1) IgM test is a blood test that detects IgM antibodies against HSV-1. These antibodies usually appear early after initial infection or during viral reactivation, making IgM a marker of recent or acute infection. HSV-1 most often causes oral herpes (cold sores), but it can also cause genital herpes and other complications.

Uses

This test is used to:

• Detect recent or acute HSV-1 infection.
• Differentiate between early infection and long-term exposure (which is usually tested with HSV-1 IgG).
• Assist in diagnosing unexplained oral or genital lesions when acute herpes is suspected.
• Support testing in immunocompromised patients at risk of severe HSV complications.

Symptoms That May Lead to the Test

A doctor may recommend this test if you have symptoms such as painful oral or genital blisters, recurrent ulcers, fever, burning or tingling sensations around the mouth or genitals, or swollen lymph nodes. It may also be used in suspected primary herpes infection after exposure.

Abnormal Results

Positive HSV-1 IgM: Indicates recent or acute HSV-1 infection, or viral reactivation. Confirmation with clinical findings and possibly HSV PCR may be required.

Negative HSV-1 IgM: Suggests no recent infection. If HSV-1 IgG is positive, it may indicate past exposure without current activity.

Note: IgM tests may sometimes cross-react, leading to false positives; follow-up tests may be advised.

Risks

The test involves a routine blood draw. Risks are minimal, such as mild bruising, slight pain, or dizziness, which usually resolve quickly.