Purpose: To determine if someone has been exposed to CMV in the past (latent infection) or has developed immunity.

Sample Type: Blood sample (serum).

Procedure: Blood is drawn from a vein, usually in the arm, and then tested for the presence of IgG antibodies specific to CMV.

For healthy individuals, past exposure to CMV usually does not pose a risk. However, CMV can cause complications for:

• • Immunocompromised individuals (e.g., those with HIV/AIDS or undergoing chemotherapy).
  • Pregnant women, as CMV can be passed to the fetus and potentially cause congenital infections.
  • Newborns, if the mother has an active CMV infection during pregnancy.

Normal Range 

• Negative (<0.6 AU/mL or <0.9 AU/mL): No detectable IgG antibodies; indicates no past exposure to CMV or possible waning immunity.
• Equivocal (0.6-0.8 AU/mL or 0.9-1.0 AU/mL): Borderline result; a retest might be recommended to clarify immune status.
• Positive (>0.8 AU/mL or >1.0 AU/mL): Presence of IgG antibodies; indicates past exposure or immunity to CMV.

Interpretation of Results

• IgG Positive and IgM Negative: Indicates past CMV infection, often meaning immunity.
• IgG Positive and IgM Positive: Suggests a recent or active infection.
• IgG Negative: Suggests no prior CMV exposure; if the individual is at high risk (e.g., pregnant or immunocompromised), preventive measures or monitoring may be recommended.

The CMV IgG test requires a blood sample, usually obtained via venipuncture (drawing blood from a vein) from the arm.