Cytomegalovirus IgG Avidity
Label Mnemonic: CMVGAVID
Epic Lab Code: LAB5742
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
Preferred Minimum: 0.5 mL serum
Absolute Minimum: 0.25 mL serum
Delivery Instructions:
Submit specimen to laboratory as soon as possible after collection.
Turn Around Time:
5 days upon receipt at reference laboratory
Reference Range:
>= 0.60
Discrimination between recent (primary) and past cytomegalovirus (CMV) infection can be an important tool in the clinical management of transplant recipients and pregnant women. Although nearly all individuals with recent CMV infection are positive for CMV IgM, individuals with past CMV may also express CMV IgM following viral reactivation; thus, detection of CMV IgM is not a reliable indicator of recent infection. Measurement of CMV IgG avidity can assist in discriminating recent from past CMV infection. Although a low avidity index is a reliable indicator of CMV infection within the previous 6 months, a high avidity index is more meaningful from a clinical standpoint; a high avidity index essentially excludes the possibility that infection occurred within the previous 4 months. In summary, assessment of CMV-specific IgG avidity is an extremely powerful tool for estimating the time of CMV infection. Such information is particularly important in the clinical management of pregnant women found to be positive for CMV antibodies at their first prenatal visit. Determining the time of primary infection can help guide decisions regarding antiviral therapy by identifying those women who should or should not be treated during pregnancy. CMV IgG avidity measurement also has broad applicability to the management of other patient groups with an increased risk of debilitating CMV disease, such as solid organ transplant recipients. Approximately 50% of pregnant women with primary CMV infection transmit CMV to their infants. Measuring CMV IgG avidity can reliably distinguish primary infection from active latent infection during pregnancy.
Enzyme Linked Immunosorbent Assay (ELISA)
CPT Code: