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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: CMV Ab, IgG (Immune Status)

Test Code(s): CMVIMM / XCMVG

CPT Code(s): 86644

Methodology: Chemiluminescent Immunoassay

Clinical Significance: Screening test to detect prior exposure to CMV.

Days Performed: Mon-Fri, dayshift.

Turnaround Time: Stat: Not available stat.
Routine: Next working day.

Specimen Requirements

Specimen: Blood

Collection Container: Preferred: Red cap with yellow ring (SST)
Also Acceptable: Red top

Collection Volume: Preferred: 2 mL
Pediatrics: 0.3 mL

Sample Analyzed: Serum

Volume Required: Preferred: 1 mL
Pediatrics: 0.15 mL

Specimen Processing: Centrifuge.  If a complete barrier has not formed, transfer cell-free serum to plastic vial.  Refrigerate.

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.

Stability: Ambient: 8 hours
Refrigerated: 3 days
Frozen: 6 months


Interpretive Guidelines:


Nonreactive:  CMV IgG antibody was not detected.
Indeterminate: Repeat testing within a week recommended.
Reactive: May indicate past or present CMV infection.


Test Limitations:

This method is approved for diagnostic testing only.  It is not approved for screening tissue donors that fall under FDA's HCT/P requirements.

Additional Information:

The presence of IgG antibodies in a single specimen is not sufficient to distinguish between active or past infection.


Patients suspected of having primary or active infection could be tested for the presence of IgM antibodies to CMV or CMV DNA by PCR.


Individuals with acute CMV infection may not exhibit any detectable IgG antibodies at the early stage of infection.


False reactive results may also occur in patients with measles, VZV, HSV, or EBV.  Samples containing antinuclear antibodies or other anticell antibodies may give false reactive results.


Results may be affected if patient has developed heterophilic antibodies due to exposure to animal based protein.


False negative results may occur in immunocompromised patients.


cmv immune status

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