Feedback
Cytomegalovirus Antibody, IgG Avidity
2011813
Ordering Recommendation

Order to aid in the diagnosis of cytomegalovirus (CMV) infection during pregnancy after initial testing for CMV IgM and IgG has been performed.

Mnemonic
CMV G AVID
Methodology
Semi-Quantitative Enzyme-Linked Immunosorbent Assay
Performed
Tuesday
Reported
1-8 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Serum separator tube (SST). 
Specimen Preparation
Separate serum from cells ASAP or within 2 hours of collection. Transfer 0.5 mL serum to an ARUP Standard Transport Tube. (Min: 0.15 mL) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
 
Remarks
 
Stability
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year 
Reference Interval
0.50 Index or less: Low Avidity
0.51-0.59 Index: Intermediate Avidity
0.60 Index or greater: High Avidity
Interpretive Data
Identifying CMV infections in pregnant women during the first trimester is of significant importance for clinical care. Acute infection is typically characterized by increased CMV-specific IgM and IgG antibodies. However, CMV IgM antibodies may persist for several months or even years after initial infection, which limits their utility in the accurate diagnosis of recent CMV infection. CMV IgM antibodies can also be detected during viral reactivation, thus complicating the diagnosis of a recent primary infection. Therefore, measuring IgG antibody avidity to CMV antigens can aid in discriminating recent from prior CMV infections. Index values of 0.5 or less generally indicate recent infection (within the previous 3 to 4 months). However low avidity values cannot exclude the possibility of persistent IgG antibodies with low avidity. Index values of 0.6 or greater indicate an infection occurring more than 3 months prior to testing. Because IgG avidity testing for CMV after the first trimester is not easily interpreted, detection of high avidity CMV IgG antibodies during the first trimester (12 to 16 weeks gestation) helps exclude a diagnosis of an acute CMV infection post-conception.

Compliance Statement B: This test was developed and its performance characteristics determined by ARUP Laboratories. The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Note
CPT Code(s)
86644
Components
Component Test Code*Component Chart NameLOINC
2011814CMV IgG Ab Avidity
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases