Cytomegalovirus Antibodies (IgG, IgM)

Test Code

CPT Codes
86644, 86645

Preferred Specimen
1.5 mL serum

Minimum Volume
0.7 mL

Transport Container
Plastic screw-cap vial

Transport Temperature
Room temperature

Specimen Stability
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Grossly lipemic • Grossly icteric

Immunoassay (IA)

Setup Schedule
Set up: Mon, Wed, Fri a.m.; Report available: Next day

False-positive IgM test results may be due to the presence of heterophil antibodies or presence of rheumatoid factor.

Reference Range

Cytomegalovirus Antibody (IgG)

U/mL Interpretation
<0.60 Negative
0.60-0.69 Equivocal
≥0.70 Positive
A positive result indicates that the patient has antibody to CMV. It does not differentiate between an active or past infection.

 Cytomegalovirus Antibody (IgM)

AU/mL Interpretation
<30.00 No antibody detected
30.00-34.99 Equivocal
≥35.00 Antibody detected
Results from any one IgM assay should not be used as a sole determinant of a current or recent infection. Because an IgM test can yield false positive results and low level IgM antibody may persist for more than 12 months post infection, reliance on a single test result could be misleading. Acute infection is best diagnosed by demonstrating the conversion of IgG from negative to positive. If an acute infection is suspected, consider obtaining a new specimen and submit for both IgG and IgM testing in two or more weeks.

Clinical Significance
Intrauterine or congenital CMV infections occur in 0.5 to 2.2% of all live births. Symptomatic congenital infections usually occur in infants born to non-immune mothers who have primary infections during pregnancy. Latency and reactivation of CMV influence the interpretation of serological  results. A single positive CMV IgG result is and indication of present or past infection. The presence of CMV IgM suggests a recent CMV exposure but does not differentiate between primary infection and reactivation.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.