Cytomegalovirus (CMV) Antibodies, IgM and IgG (Sendout)

General Information

Lab Name

CMV Abs, IgM and IgG, Serum

Lab Code

RCMVMG

Epic Name

CMV Antibodies, IgM and IgG, Serum (Sendout)

External Test Id

CMVP

Description

Useful For: Diagnosis of primary, acute phase infection with cytomegalovirus (CMV), especially in patients with infectious mononucleosis and pregnant women who, based on clinical signs or exposure, may have primary CMV infection. This test should not be used for screening blood or plasma donors.

Synonyms

CMV IgG/IgM, CMV IgM, CMVP, CMVSGM, Cytomegalo Inclusion Disease (CMID), Torch IgG, Torch IgM

Components

Code	Name
RCMVM	Cytomegalovirus Ab, IgM, Serum
RCMVG	Cytomegalovirus Ab, IgG, Serum

Interpretation

Method

Multiplex Flow Immunoassay (MFI)

Reference Range

See individual components

Ref. Range Notes

Reference Values:

CMV IgM:	Negative
CMV IgG:	Negative

Interpretation:

IgM: A negative cytomegalovirus (CMV) IgM result suggests that the patient is not experiencing acute or active infection. However, a negative result does not rule-out primary CMV infection.

It has been reported that CMV-specific IgM antibodies were 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 postinfection. 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.

IgG: Positive CMV IgG results indicate past or recent CMV infection. These individuals may transmit CMV to susceptible individuals through blood and tissue products.

Individuals with negative CMV IgG results are presumed to not have had prior exposure or infection with CMV and are, therefore, considered susceptible to primary infection.

Equivocal CMV IgM or IgG results may occur during acute infection or may be due to nonspecific binding reactions. Submit an additional sample for testing if clinically indicated.

Interferences and Limitations

Cautions:

Sera drawn very early during the acute stage of infection may have undetectable levels of cytomegalovirus (CMV) IgM or IgG.

Immunocompromised patients may have impaired immune responses and non-reactive IgM/IgG results may be due to delayed seroconversion and, therefore, do not rule out current infection.

The CMV IgM and IgG results should not be used alone to diagnose CMV infection. Results should be considered in conjunction with clinical presentation, patient history and other laboratory findings. In cases of suspected disease, submit a second sample for testing in 10 to 14 days.

The performance characteristics of these assays have not been evaluated in immunosuppressed or organ transplant recipients and have not been established for cord blood or for testing of neonates.

Immune complexes or other immunoglobulin aggregates present in patient samples may cause increased nonspecific binding and produce false-positive results.

Potential cross-reactivity for CMV IgM may occur with specimens positive for Epstein-Barr virus viral capsid antigen IgM and parvovirus B19 IgM.

Potential cross-reactivity for CMV IgG with human chorionic gonadotropin, HIV IgG, multiple myeloma IgG, rheumatoid factor IgM, and Toxoplasma gondii IgG have not be ruled out.

Ordering & Collection

Specimen Type: Blood
Collection: 3 mL blood in RED TOP tube or GOLD SST
Handling Instructions: Outside Laboratories: Centrifuge sample and transfer serum to a separate plastic vial. Refrigerate serum.

Stability: Refrigerated (preferred): 14 days; Frozen: 14 days; Ambient: Unacceptable.

Reject Due To: Gross hemolysis, gross lipemia, gross icterus, heat-inactivated specimen.
Quantity: Requested: 1 mL serum
Minimum: 0.8 mL serum

Processing

Receiving Instructions

Centrifuge and transfer serum to a separate vial. Refrigerate.

Sendouts:

Order Mayo Test: CMVP.
Interfaced: Yes.

Stability: Refrigerated (preferred): 14 days; Frozen: 14 days; Ambient: Unacceptable.

Reject Due To: Gross hemolysis, gross lipemia, gross icterus, heat-inactivated specimen.

Misc Sendout

Performance

Lab Department

Sendouts Mayo Lab (RF)(MARF)

Frequency

Performed: Monday - Saturday. Report Available: 1-3 days.

Available STAT?

Performing Location(s)

Sendout	Mayo Clinic Laboratories (Superior Drive) 800-533-1710 3050 Superior Drive NW Rochester, MN 55901

Billing & Coding

CPT Codes: 86644, 86645
LOINC: 24315-4
Interfaced Order Code: UOW3000