Cytomegalovirus Antibodies (IgG, IgM)

6732

1.5 mL serum

0.7 mL

Plastic screw-cap vial

Room temperature

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

Gross hemolysis • Grossly lipemic • Grossly icteric

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.

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.

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.