Cytomegalovirus, Immunoglobulin G, and Immunoglobulin M

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Cytomegalovirus, Immunoglobulin G, and Immunoglobulin M

Synonym/acronym: CMV.

Common use

To assist in diagnosing cytomegalovirus infection.


Serum (1 mL) collected in a plain red-top tube.

Normal findings

(Method: Enzyme immunoassay)
IgM & IgGInterpretation
Negative0.9 index or lessNo significant level of detectable antibody
Indeterminate0.91–1.09 indexEquivocal results; retest in 10–14 d
Positive1.1 index or greaterAntibody detected; indicative of recent immunization, current or recent infection


Cytomegalovirus (CMV) is a double-stranded DNA herpesvirus. The Centers for Disease Control and Prevention (CDC) estimates that 50% to 85% of adults are infected by age 40. The incubation period for primary infection is 4 to 8 wk. Transmission may occur by direct contact with oral, respiratory, or venereal secretions and excretions. CMV infection is of primary concern in pregnant or immunocompromised patients or patients who have recently received an organ transplant. Blood units are sometimes tested for the presence of CMV if patients in these high-risk categories are the transfusion recipients. CMV serology is part of the TORCH (toxoplasmosis, other [congenital syphilis and viruses], rubella, CMV, and herpes simplex type 2) panel used to test pregnant women. CMV, as well as these other infectious agents, can cross the placenta and result in congenital malformations, abortion, or stillbirth. The presence of immunoglobulin (Ig) M antibodies indicates acute infection. The presence of IgG antibodies indicates current or past infection. There are numerous methods for detection of CMV. The methodology selected is based on both the test purpose and specimen type. Other types of assays used to detect CMV include direct fluorescent assays used to identify CMV in tissue, sputum, and swab specimens; hemagglutination assays, cleared by the FDA for testing blood prior to transfusion; polymerase chain reaction (PCR), used to test a wide variety of specimen types, including amniotic fluid, plasma, urine, CSF, and whole blood; and cell tissue culture, which remains the gold standard for the identification of CMV.

This procedure is contraindicated for



  • Assist in the diagnosis of congenital CMV infection in newborns
  • Determine susceptibility, particularly in pregnant women, immunocompromised patients, and patients who recently have received an organ transplant
  • Screen blood for high-risk-category transfusion recipients

Potential diagnosis

Positive findings in:

  • CMV infection

Critical findings


Interfering factors

  • False-positive results may occur in the presence of rheumatoid factor.
  • False-negative results may occur if treatment was begun before antibodies developed or if the test was done less than 6 days after exposure to the virus.

Nursing Implications and Procedure

Potential nursing problems

ProblemSigns & SymptomsInterventions
Infection (Related to viral infection secondary to blood transfusion; organ transplant; sexual contact; exposure to respiratory droplets)Fever, fatigue, loss of appetite; malaise; muscle aches; headache; irregular heartbeat; stiff neck; shortness of breath; swollen liver or spleen; tachycardia; rash; sore throat; increased blood pressure; elevated IgM, IgG Promote good hygiene; assist with hygiene as needed; administer prescribed antivirals as appropriate, antipyretics; administer cooling measures; monitor vital signs and trend temperatures; encourage oral fluids; adhere to standard or universal precautions; provide isolation as appropriate; obtain cultures as ordered; assess nutritional status and provide supplements as needed
Fatigue (Related to infection and inflammation)Report of tiredness; inability to maintain activities of daily living at current level; inability to restore energy after rest or sleep Discuss the implementation of energy conservation activities (even pace when working, frequent rest periods, frequent items in easy reach, push items instead of pulling); limit naps to increase nighttime sleeping; set priorities for energy expenditures; administer ordered antibiotics
Sexuality (Related to positive CMV [herpes virus])Reduced sexual function; decreased sexual satisfaction; reports of alteration in relationship with partner Assess perception of reported change in sexual function; assess emotional impact of herpes diagnosis (depression, altered self-esteem, altered personal relationships); assess need for counseling; encourage verbalization of feelings; discuss alternative forms of intimate expression; discuss medical treatments that may improve sexual interaction


  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this test can assist in identification of the organism causing infection.
  • Obtain a history of the patient’s complaints and history of exposure. Obtain a list of known allergens, especially allergies or sensitivities to latex.
  • Obtain a history of the patient’s immune and reproductive systems, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • Review the procedure with the patient. Inform the patient that multiple specimens may be required. Any individual positive result should be repeated in 7 to 14 days to monitor a change in titer. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Note that there are no food, fluid, or medication restrictions, unless by medical direction.


  • Potential complications: N/A
  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
  • Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
  • Promptly transport the specimen to the laboratory for processing and analysis.


  • Inform the patient that a report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient. Some HCPs may take additional precautions in the case of CMV antibody negative immunocompromised or pregnant patients by requesting CMV antibody negative blood products or organs in the event those interventions are required.
  • Instruct the patient in isolation precautions during time of communicability or contagion.
  • Emphasize the need to return to have a convalescent blood sample taken in 7 to 14 days.
  • Warn the patient that there is a possibility of false-negative or false-positive results.
  • Recognize anxiety related to test results if the patient is pregnant, and offer support. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Educate the patient regarding access to counseling services.
  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
  • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
  • Patient Education

    • Provide emotional support if the patient is pregnant and if results are positive.
    • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
    • Answer any questions or address any concerns voiced by the patient or family.
  • Expected Patient Outcomes

    • Knowledge
    • States understanding that it may take up to 6 wk for full recovery from the diagnosed viral infection
    • States understanding that once CMV virus is in an individual, it will remain present for the rest of his or her life.
    • States emergency response number and understands to call for severe abdominal pain that could indicate a ruptured spleen requiring emergency surgery.
    • Skills
    • Demonstrates proficiency in using warm saltwater gargles for comfort with sore throat
    • Attitude
    • Complies with the recommendation of infected persons to refrain from kissing or other sexual contact to prevent infecting others
    • Complies with the request to stay at home while infectious to avoid exposing others

Related Monographs

  • Related tests include β2-microglobulin, bronchoscopy, Chlamydia group antibody, culture viral, cytology urine, HIV-1/2 antibodies, Pap smear, rubella antibody, and Toxoplasma antibody.
  • Refer to the Immune and Reproductive systems tables at the end of the book for related tests by body system.
Handbook of Laboratory and Diagnostic Tests, © 2013 Farlex and Partners