VARICELLA ZOSTER VIRUS (VZV) IGM ANTIBODIES

Varicella Zoster Virus (VZV) IgM Antibodies, Serum

What it is

The Varicella Zoster Virus (VZV) IgM Antibodies test detects IgM antibodies in the blood, which are produced by the body in response to a recent or active infection with VZV. This virus causes chickenpox (primary infection) and shingles (reactivation later in life). The presence of IgM antibodies typically indicates a current or very recent infection.

Uses

This test is used to diagnose acute or recent VZV infection, helping distinguish between past exposure (IgG) and current infection (IgM). It is particularly useful in patients with atypical rashes, immunocompromised individuals, newborns with suspected congenital infection, or adults with suspected shingles where confirmation is needed.

Symptoms That May Lead to the Test

Doctors may order this test if you have symptoms suggestive of chickenpox or shingles, such as fever, itchy vesicular rash, headache, fatigue, or painful blister-like skin eruptions following nerve pathways. In newborns, it may be ordered if congenital infection is suspected due to maternal exposure during pregnancy.

Abnormal Results

Positive IgM: Indicates a recent or active varicella or shingles infection. However, false positives can occur, so results are often interpreted along with IgG levels, clinical findings, and sometimes PCR testing.

Negative IgM: Suggests no current infection. If symptoms are present but the test is negative, follow-up testing may be recommended as IgM antibodies can take time to appear.

Risks

This test involves a standard blood draw with minimal risks such as mild pain, slight bruising, or temporary dizziness. These effects are uncommon and generally harmless.