CMV IgM

Function

The CMV IgM test detects IgM antibodies to Cytomegalovirus. These antibodies are the first type produced by the body in response to a new CMV infection. They typically appear within 1-2 weeks of exposure and remain detectable for several months, though they can sometimes persist longer.

Why it is Ordered

This test is used to determine if a patient has a current or very recent primary CMV infection. It is frequently ordered for:

• Pregnant women who exhibit symptoms of a viral infection or have had a known exposure.
• Individuals with symptoms of mononucleosis (fever, fatigue, swollen glands) who test negative for the Epstein-Barr virus (EBV).
• Organ donors and recipients to determine serostatus.

Associated Conditions

• Primary CMV Infection: The first time an individual is exposed to the virus.
• Reactivation/Reinfection: In some cases, IgM can reappear when a latent infection reactivates, though this is less common than in primary infection.
• Congenital Infection: Testing of the mother and infant can help identify risk factors for birth defects or developmental delays caused by the virus.