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Test ID: LCMV    
Cytomegalovirus (CMV), Molecular Detection, PCR

Useful For Suggests clinical disorders or settings where the test may be helpful

Rapid qualitative detection of cytomegalovirus DNA

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Infection with cytomegalovirus (CMV) is a significant cause of morbidity and mortality in transplant recipients and other immunocompromised hosts. Specific neurologic syndromes associated with CMV infection include subacute radiculomyelopathy, peripheral neuropathy, and encephalitis. 

 

CMV-associated central nervous system (CNS) disease occurs most commonly in immunocompromised patients. Histologic evidence of CMV infections in autopsy brain tissue was identified in 20% to 40% of AIDS patients. In 2 separate studies, CMV (DNA) was the most common herpesvirus (29/181, 16/49) detected from cerebrospinal fluid of patients with AIDS. 

 

CNS infections with CMV can also occur in immunocompetent patients. CMV is a leading cause of congenital viral infections worldwide, and laboratory testing by real-time PCR is useful in the diagnosis of neonatal CMV disease.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Negative

Interpretation Provides information to assist in interpretation of the test results

Detection of cytomegalovirus (CMV) DNA in a specimen supports the clinical diagnosis of infection due to this virus.

 

Studies indicate that CMV DNA is not detected by PCR in cerebrospinal fluid from patients without central nervous system disease caused by this virus.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

A negative result does not eliminate the possibility of cytomegalovirus (CMV) infection.

 

This assay is only to be used for patients with a clinical history and symptoms consistent with CMV infection, and must be interpreted in the context of the clinical picture. This test should not be used to screen asymptomatic patients.

Supportive Data

The following validation data support the use of this assay for clinical testing.

            

Accuracy:

A total of 200 prospective clinical samples (respiratory [n=72], urine [n=67], spinal fluid [n=25], fresh tissue [n=18], amniotic fluid [n=10], and bone marrow [n=8]) were submitted to our reference laboratory for cytomegalovirus (CMV) real-time PCR (Roche analyte specific reagents [ASR], Roche Diagnostics, Indianapolis, IN). Respiratory samples included bronchoalveolar lavage (BAL) fluid (n=25), bronchial washing (n=40), nasal swab (n=4), tracheal secretions (n=2), and throat swab (n=1). Each sample was tested by 6 real-time PCR assays, and the results were compared to consensus reference standard (4 of 6 results being in agreement). The performance of the US9 CMV real-time PCR (laboratory-developed test is summarized in Table 1 below:

 

Table 1. Performance of the US9 CMV real-time PCR assay following testing of prospective clinical samples (n=200)

US9 CMV PCR

Consensus Result

 

 

 

Positive

Negative

Kappa

Sensitivity

Specificity

Positive

45

0

0.99

97.8 (87.6–99.9)

100 (97.1–100)

Negative

1

154

 

 

 

 

Analytical Sensitivity/Limit of Detection (LoD):

To evaluate the analytical sensitivity, whole virus control (Acrometrix, Life Technologies) at a starting concentration of 500,000 copies/mL was used to generate a dilution panel. In brief, samples were diluted 1:2 in tris-EDTA buffer to a final concentration of 8 copies/mL. Each member of the dilution panel was then tested in triplicate, with the LoD being defined as the highest dilution at which all replicates tested positive. The LoD was determined to be 122 copies/mL.(1)  

 

Analytical Specificity:

No PCR signal was obtained from extracts of 44 bacterial and viral isolates including Epstein-Barr virus, herpes simplex virus, varicella-zoster virus, human herpes virus-6 (HHV6), HHV7, HHV8, and parvovirus.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Espy M, Binnicker MJ: Comparison of six real-time PCR assays for the qualitative detection of cytomegalovirus in clinical specimens. J Clin Microbiol 2013:51(11):3749-3752

2. Petito CK, Cho ES, Lemann W, et al: Neuropathy of acquired immunodeficiency syndrome (AIDS): an autopsy review. J Neuropathol Exp Neurol 1986 November;45(6):635-646

3. Cinque P, Vago L, Dahl H, et al: Polymerase chain reaction on cerebrospinal fluid for diagnosis of virus-associated opportunistic diseases of the central nervous system in HIV-infected patients. AIDS 1996 August;10(9):951-958

4. Broccolo F, Iulioano R, Careddu AM, et al: Detection of lymphotropic herpesvirus DNA by polymerase chain reaction in cerebrospinal fluid of AIDS patients with neurological disease. Acta Virol 2000 June-August;44(3):137-143

5. Prosch S, Schielke E, Reip A, et al: Human cytomegalovirus (HCMV) encephalitis in an immunocompetent young person and diagnostic reliability of HCMV DNA PCR using cerebrospinal fluid of nonimmunosuppressed patients. J Clin Microbiol 1998 December;36(12):3636-3640

6. Sia IG, Patel R: New strategies for prevention and therapy of cytomegalovirus infection and disease in solid-organ transplant recipients. Clin Microbiol Rev 2000;13:83-121