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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: CMV Quantitative by PCR

Test Code(s): CMVDNA / HCCMVDNA

CPT Code(s): 87497

Methodology: Real-Time PCR

Clinical Significance: Detect and quantitate CMV in blood.

Days Performed: Mon-Fri.

Turnaround Time: Stat: Not available stat.
Routine: 2 - 3 days.


Specimen Requirements

Specimen: Blood

Collection Container: Preferred: Lavender top
Also Acceptable: K2EDTA Plasma Preparation Tube (PPT)

Collection Volume: Preferred: 6 mL
Pediatrics: 2 mL

Sample Analyzed: Plasma

Volume Required: Preferred: 3 mL
Pediatrics: 1.2 mL

Specimen Processing: For optimal specimen, separate cell-free plasma from whole blood and transfer to a sterile polypropylene tube preferrably within 6 hours of collection.  Freeze plasma at -60 to -80C (preferred). Prior to freezing, EDTA plasma may also be stored at either 2 to 8C or frozen at -20C for up to 7 days.

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220) immediately. If frozen, transport separated plasma on dry ice and keep frozen.

Outreach Specimen Transport: Transport whole blood or separated plasma (preferred) at room temperature to UWHC Core Laboratory (B4/220) using priority overnight delivery only.

Unacceptable Criteria: LIMIT: One specimen every 48 hours.

Stability: Ambient: 3 days
Refrigerated: 3 days
Frozen: Whole blood- Not acceptable; Plasma- Indefinitely at -70 C or 7 days at -20C.


Interpretation

Expected Results:

Not detected

 

The reported concentration of CMV virus particles in blood may indicate viremia levels and treatment efficacy.

Test Limitations:

Analytical measurement range for this test is 200-10,000,000 copies/mL (2.30-7.00 log10 copies/mL) of plasma. Detection range is 10 - unlimited copies per mL of plasma.

Additional Information:

For plasma samples in which CMV DNA is detected and between the analytical measurement range (AMR), a quantitative value (copies/mL) will be reported. If CMV DNA is detected, but below 200 copies/mL, a result of "Detected, below AMR" will be reported.  A result of >10,000,000 copies/mL will be reported as "Detected, above AMR."  If CMV DNA is not detected, a result of "Not detected" will be reported.

    

A result of "not detected" does not rule out the presence of CMV DNA or the absence of infection. False negative results may be due to the suppression of viral replication to levels below the detection threshold, or to inhibitory substances that may be present in the specimen. Inadequate specimen collection, processing and storage may invalidate test results. This test should not be used as the only criterion to form a clinical conclusion, instead, results should be correlated with other test results, patient symptoms and clinical presentation.
   
DNA sequence polymorphisms in CMV strains may underestimate viral levels. The presence of variations in CMV DNA sequences are monitored in the real-time PCR assay and, if detected, the sample is retested using reagents to alternate amplification targets to verify CMV detection and quantification. This assay does not genotype the virus, and consequently does not provide any information with regard to CMV drug resistance.

   

The performance characteristics of this test were validated by UWHC Clinical Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test; however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. The UWHC Clinical Laboratories is authorized under Clinical Laboratory Improvement Amendments (CLIA) to perform high-complexity testing.

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