Sorted By Test Name - Mayo Medical Laboratories

CMG
80750
known. A ratio of > or =2 in paired sera (acute and convalescent) IgG values, along with a convalescent
antibody level of >6, indicates a seroconversion has occurred and may be indicative of a recent infection.
CMV infections are quite common. Approximately 60% to 85% of the population is believed to be
infected by age 18. IgM: Negative CMV IgM results suggest that an individual is not experiencing a
recent infection. However, a negative result does not rule out primary CMV infection. It has been reported
that CMV-specific IgM antibody was not detectable in 10% to 30% of cord blood sera from infants
demonstrating infection in the first week of life. In addition, up to 23% (3/13) of pregnant women with
primary CMV infection did not demonstrate detectable CMV IgM responses within 8 weeks
post-infection. In cases of primary infection where the time of seroconversion is not well defined, as high
as 28% (10/36) of pregnant women did not demonstrate CMV IgM antibody. Positive CMV IgM results
indicate a recent infection (primary, reactivation, or reinfection). IgM antibody responses in secondary
(reactivation) CMV infections have been demonstrated in some CMV mononucleosis patients, in a few
pregnant women, and in renal and cardiac transplant patients. Levels of antibody may be lower in
transplant patients with secondary rather than primary infections.
Reference Values:
CYTOMEGALOVIRUS ANTIBODIES, IgG
or =6 AU/mL (positive)
CYTOMEGALOVIRUS ANTIBODIES, IgM
Negative (reported as positive or negative)
The presence of IgM class antibodies or a convalescent IgG antibody level of >6 AU/mL combined with
a ratio of > or =2 in a paired sera (seroconversion) IgG titer indicates recent infection. The presence of
only IgG antibodies generally indicates past infection with CMV.
Clinical References: 1. Kusne S, Shapiro R, Fung J: Prevention and treatment of cytomegalovirus
infection in organ transplant recipients. Transpl Infect Dis 1999;1(3):187-203 2. Rubin RH: Importance of
CMV in the transplant population. Transpl Infect Dis 1999;1(1):3-7 3. Lang D, Vornhagen R, Rothe M, et
al: Cross-reactivity of Epstein-Barr virus-specific immunoglobulin M antibodies with cytomegalovirus
antigens containing glycine homopolymers. Clin Diagn Lab Immunol 2001 July;8(4):747-756
Cytomegalovirus (CMV) Antibodies, IgG, Serum
Clinical Information: Cytomegalovirus (CMV) is a significant cause of morbidity and mortality,
especially in organ transplant recipients and individuals with acquired immunodeficiency syndrome
(AIDS). (1,2) CMV is also responsible for congenital disease of the newborn. The most common
infections with CMV in immunocompromised hosts result from reactivation of latent virus from a
previous infection, transmission of the virus from a donor organ or blood product, or initial or primary
contact with the virus in a seronegative patient. Infection in immunologically normal patients can cause
mononucleosis similar to that produced by infection with Epstein-Barr virus (EBV).
Useful For: Determining whether a patient (especially organ donors, blood donors, and prospective
transplant recipients) had cytomegalovirus (CMV) infection in the past Excluding CMV current infection
(cord blood)
Interpretation: Individuals with negative cytomegalovirus (CMV) IgG results are presumed to have
not experienced infection with CMV and, therefore, are susceptible to primary infection. Positive CMV
IgG results indicate past or current CMV infection. Such individuals are potentially at risk of transmitting
CMV infection through blood products; the likelihood of transmission by other modes is not known. A
ratio of > or =2 in paired sera (acute and convalescent) IgG values, along with a convalescent antibody
level of >6, indicates a seroconversion has occurred and is indicative of a recent infection. CMV
infections are quite common. Approximately 60% to 85% of the population is believed to be infected by
age 18.
Reference Values: