Cytomegalovirus - CMV

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Content

Indications for Testing

  • Mononucleosis-like illness in immunocompetent patients who test negative for EBV
  • Suspected CMV infection in immunocompromised patients
  • Congenital syndromes suspicious for CMV
  • Pretransplant and posttransplant screening

Laboratory Testing

  • Acute disease confirmation in immunocompetent patients – order acute and convalescent serology
    • Elevated IgM provides evidence of current infection or reactivation
      • Four-fold increase in IgG titers using paired specimens 10-14 days apart is suggestive of recent infection
  •  Acute disease in immunocompromised patients – serology not helpful
    • Quantitative measurement by PCR defines viral load
    • Gold standard – tissue culture
      • Biopsy of affected tissue site or bronchoalveolar lavage
  • Transplant patients
    • Pretransplant screening
      • IgG testing of donor and recipient
      • CMV-specific CD8 T cells – aids in determining risk of CMV infection posttransplant
    • Posttansplant screening
      • Hematopoietic stem cell (HSCT) (Tomblyn, 2009)
        • Screen 7-10 days posttransplant
        • Screen until at least 100 days posttransplant
      • Renal transplant (KIDGO, 2009)
        • Viral load monitoring for patients deemed moderate risk for CMV
  • Primary infection in pregnant women
    • CMV IgG avidity testing to distinguish between primary and secondary infection
      • Low avidity suggests CMV infection within last 3-4 months (increased risk for infant with congenital CMV)
    • Acute and convalescent serology – may be less helpful than avidity testing
      • IgM may remain positive for months
      • IgM may elevate in reactivated disease
      • Use same criteria as immunocompromised patients for active infection
    • Amniotic fluid – PCR testing
      • Most sensitive >21 weeks gestation
  • Congenital disease
    • Rapid culture of urine (early antigen detection)
    • PCR on blood or body fluids
    • Test within first 3 weeks to exclude perinatal infection
    • Consider testing for other congenital syndromes if CMV not clearly identified as etiology of congenital disease
  • Interpretation of CMV laboratory tests (CDC)

Histology

  • Presence of characteristic intranuclear and intracytoplasmic inclusions confirms diagnosis
  • Cytomegalovirus IHC stain may be useful in tissue

Prognosis

  • Neonatal – poor outcome associated with the following
    • Cerebrospinal fluid protein >120 mg/dL
    • CT – calcifications/microcephaly
    • Fetal ultrasound – placentomegaly; observed fetal anatomic abnormalities

Differential Diagnosis

Cytomegalovirus (CMV) is generally asymptomatic in immunocompetent children and adults, but is a potentially significant disease in immunocompromised hosts, neonates, and pregnant females.

Epidemiology

  • Incidence
    • ~70% of adults in the U.S. are seropositive
    • 1-2% of U.S. population infected yearly
  • Transmission
    • Transplacental (congenital), perinatal (human milk, cervical secretions)
    • Blood transfusion
    • Organ transplantation (both solid and hematopoietic)
    • Infectious droplet (normal childhood route)
      • CMV excreted in all secretions except tears
    • Sexual contact

Organism

  • Largest member of the herpesvirus family; double-stranded DNA virus
  • Ability to remain latent (feature of all herpes viruses)
  • Large intranuclear and cytoplasmic inclusions produced in tissues by CMV are the hallmark of the disease

Risk Factors for Disease

  • HIV
  • Organ transplantation
  • Immunocompromised status
  • Maternal infections or reinfections – leads to congenital disease

Clinical Presentation

Prevention

  • Blood transfusions
    • Seronegative individuals transfused with blood from seropositive donors have a high risk of developing CMV infection
    • Serologic testing for CMV is important in screening blood for transfusion to neonates or to immunocompromised patients
    • Use of leukocyte-reduced blood products greatly reduces the risk of transfusion-associated transmission

Indications for Laboratory Testing

Tests generally appear in the order most useful for common clinical situations.
Click on number for test-specific information in the ARUP Laboratory Test Directory

Cytomegalovirus Rapid Culture 0065004
Method: Cell Culture/Immunofluorescence

Cytomegalovirus by Qualitative PCR 0060040
Method: Qualitative Polymerase Chain Reaction

Limitations

PCR on amniotic fluid should be performed >21 weeks' gestation to reduce risk of false negatives

Cytomegalovirus by PCR, Whole Blood or Bone Marrow 0060031
Method: Qualitative Polymerase Chain Reaction

Cytomegalovirus by Quantitative PCR 0051813
Method: Quantitative Polymerase Chain Reaction

Limitations

The quantitative range of this test is 2.6-6.6 log copies/mL (390-3,900,000 copies/mL) or 2/4-6.4 log IU/mL (227-2,270,000 IU/mL)

One IU/mL of CMV DNA is ~1.72 copies/mL

Negative result (<2.6 log copies/mL [<390 copies/mL] OR <2.4 log IU/mL [<227 IU/mL]) does not rule out presence of PCR inhibitors or DNA concentrations below the level of detection

Inhibition may also lead to underestimation of viral quantitation

Cytomegalovirus, Quantitative PCR with Reflex to Drug Resistance Testing by Sequencing 2006966
Method: Quantitative Polymerase Chain Reaction/Sequencing

Limitations

Limit of quantification for this DNA assay is 2.6 log copies/mL (390 copies/mL); if the assay DID NOT DETECT the virus, the test result will be reported as <2.6 log copies/mL (<390 copies/mL)

If assay DETECTED presence of virus but was unable to accurately quantify number of copies, test result will be reported as not quantified

Negative result does not rule out presence of PCR inhibitors or DNA concentrations below the level of detection

Cytomegalovirus Antibody, IgG Avidity 2011813
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Limitations

Avidity index cannot be calculated for patients who are negative for CMV IgG antibodies

Cytomegalovirus Antibodies, IgG and IgM 0050622
Method: Semi-Quantitative Chemiluminescent Immunoassay

Limitations

Not recommended for immunocompromised patients

Rise in CMV antibody level may occur in patients with measles, VZV or HSV due to antigenic cross-reactivity within the herpesvirus family

Infants may test positive during first 6 months due to maternal antibodies

Cytomegalovirus (CMV) by Immunohistochemistry 2003833
Method: Immunohistochemistry

Additional Tests Available

Cytomegalovirus Antibody, IgM 0050553
Method: Semi-Quantitative Chemiluminescent Immunoassay

Comments

Use for suspicion of cytomegalovirus (CMV) infection during pregnancy as indicated by positive IgM and/or IgG tests

CMV serology is not useful for the evaluation of active or reactivated infection in immunocompromised patients; molecular diagnostic tests (ie, PCR) are preferred in these cases

Cytomegalovirus Antibody, IgG 0050165
Method: Semi-Quantitative Chemiluminescent Immunoassay

Comments

Determine previous CMV infection

Cytomegalovirus Antiviral Drug Resistance by Sequencing 2004760
Method: Polymerase Chain Reaction/Sequencing

TORCH Antibodies, IgG 0050772
Method: Semi-Quantitative Chemiluminescent Immunoassay/Quantitative Chemiluminescent Immunoassay

TORCH Antibodies, IgM 0050665
Method: Semi-Quantitative Chemiluminescent Immunoassay/Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Viral Culture, Non-Respiratory and Cytomegalovirus Rapid Culture 2006496
Method: Cell Culture/Immunofluorescence

Comments

For best results, specify specimen source and suspected virus on order form; molecular diagnostics are preferred for suspected invasive CMV

Viruses that can be isolated – adenovirus, CMV, enterovirus, HSV, and VZV

Virus-specific tests are recommended

Viral Culture, Non-Respiratory 2006498
Method: Cell Culture

Comments

Generally, virus-specific testing (eg, antigen detection or molecular) is recommended

Viruses that can be isolated by culture – adenovirus, CMV, enterovirus, HSV, and VZV

Virus-specific tests are recommended

Viral Culture, Respiratory 2006499
Method: Cell Culture

Comments

Detect common respiratory viruses; molecular methods may offer improved sensitivity

Respiratory viruses rapid culture offers faster turnaround time

Viruses that can be isolated – adenovirus; CMV; enterovirus; HSV; influenza A and B; parainfluenza types 1,2, and 3; RSV; and VZV

Virus-specific tests are recommended

Viral Culture, Respiratory and Cytomegalovirus Rapid Culture 2006497
Method: Cell Culture/Immunofluorescence

Comments

Molecular diagnostics are preferred for suspected invasive CMV

Viruses that can be isolated – adenovirus; CMV; enterovirus; HSV; influenza A and B; parainfluenza types 1,2, and 3; RSV; and VZV

Virus-specific tests are recommended

Guidelines

Kidney Disease: Improving Global Outcomes (KDIGO) Transplant Work Group. KDIGO clinical practice guideline for the care of kidney transplant recipients. Am J Transplant. 2009; 9 Suppl 3: S1-155. PubMed

Tomblyn M, Chiller T, Einsele H, Gress R, Sepkowitz K, Storek J, Wingard J, Young J, Boeckh M, Boeckh M, Center for International Blood and Marrow Research, National Marrow Donor program, European Blood and MarrowTransplant Group, American Society of Blood and Marrow Transplantation, Canadian Blood and Marrow Transplant Group, Infectious Diseases Society of America, Society for Healthcare Epidemiology of America, Association of Medical Microbiology and Infectious Disease Canada, Centers for Disease Control and Prevention. Guidelines for preventing infectious complications among hematopoietic cell transplantation recipients: a global perspective. Biol Blood Marrow Transplant. 2009; 15(10): 1143-238. PubMed

General References

Bhatia P, Narang A, Minz R. Neonatal cytomegalovirus infection: diagnostic modalities available for early disease detection. Indian J Pediatr. 2010; 77(1): 77-9. PubMed

Boeckh M, Geballe A. Cytomegalovirus: pathogen, paradigm, and puzzle. J Clin Invest. 2011; 121(5): 1673-80. PubMed

Crough T, Khanna R. Immunobiology of human cytomegalovirus: from bench to bedside. Clin Microbiol Rev. 2009; 22(1): 76-98, Table of Contents. PubMed

de Jong E, Vossen A, Walther F, Lopriore E. How to use... neonatal TORCH testing. Arch Dis Child Educ Pract Ed. 2013; 98(3): 93-8. PubMed

Del Pizzo J. Focus on diagnosis: congenital infections (TORCH). Pediatr Rev. 2011; 32(12): 537-42. PubMed

DeVries J. The ABCs of CMV. Adv Neonatal Care. 2007; 7(5): 248-55; quiz 256-7. PubMed

Hirsch M, et al. Cytomegalovirus and Human Herpesvirus Types 6, 7, and 8. In Kasper D et al, eds. Harrison's Principles of Internal Medicine, 16th ed. New York: McGraw-Hill, 2005.

Lazzarotto T, Guerra B, Lanari M, Gabrielli L, Landini M. New advances in the diagnosis of congenital cytomegalovirus infection. J Clin Virol. 2008; 41(3): 192-7. PubMed

Neu N, Duchon J, Zachariah P. TORCH infections. Clin Perinatol. 2015 Mar;42(1):77-103, viii. PubMed

Plosa E, Esbenshade J, Fuller P, Weitkamp J. Cytomegalovirus infection. Pediatr Rev. 2012; 33(4): 156-63; quiz 163. PubMed

Yinon Y, Farine D, Yudin M. Screening, diagnosis, and management of cytomegalovirus infection in pregnancy. Obstet Gynecol Surv. 2010; 65(11): 736-43. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology®

Kim J, Goulston C, Sanders S, Lampas M, Zangari M, Tricot G, Hanson K. Cytomegalovirus reactivation following autologous peripheral blood stem cell transplantation for multiple myeloma in the era of novel chemotherapeutics and tandem transplantation. Biol Blood Marrow Transplant. 2012; 18(11): 1753-8. PubMed

Owen W, Martins T, Litwin C, Roberts W. Performance characteristics of six IMMULITE 2000 TORCH assays. Am J Clin Pathol. 2006; 126(6): 900-5. PubMed

Prince H, Lapé-Nixon M, Brenner A, Pitstick N, Couturier M. Potential impact of different cytomegalovirus (CMV) IgM assays on an algorithm requiring IgM reactivity as a criterion for measuring CMV IgG avidity. Clin Vaccine Immunol. 2014; 21(6): 813-6. PubMed

Ravkov E, Pavlov I, Hanson K, Delgado J. Validation of cytomegalovirus immune competence assays for the characterization of CD8(+) T cell responses posttransplant. Clin Dev Immunol. 2012; 2012: 451059. PubMed

Medical Reviewers

Last Update: January 2016