Cytomegalovirus Avidity

CMV IgG Avidity, Cytomegalovirus IgG Avidity

Test Codes

EPIC: LAB1231485, Beaker: XMISC, MAYO: FCYTG

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube.
Also acceptable: One plain Red-top tube.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 7 days
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): 30 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN. Forwarded to Quest/Focus, San Juan Capistrano, CA.

Performed

Sunday, Tuesday – Friday.
Results available in 4-8 days.

Reference Range

By report.

Test Methodology

Immunoassay.

Clinical Utility

Cytomegalovirus (CMV) IgG Avidity is used to distinguish between recent (primary) and past CMV infections. Although nearly all individuals with recent CMV infection are positive for CMV IgM, individuals with past CMV infection may also express CMV IgM following viral reactivation therefore the detection of CMV IgM is not a reliable indicator of recent infection. CMV IgG Avidity measure the strength to which the IgG attaches to the antigen. CMV IgG avidity produced within the first few months following a primary infection exhibits low avidity, whereas CMV IgG produced several months or years later exhibits high avidity. The presence of CMV high avidity IgG essentially excludes the possibility that infection occurred within the previous 4 months.

CPT Codes

86644
LOINC:  52984-2

Contacts

Last Updated

7/10/2025