CYTOMEGALOVIRUS QUANTITATIVE BY PCR

Mnemonic

CMVQNT

Synonym

CMV - CMV Titer - CMV Quant PCR - CMV quantitative - CMV Viral Load - CMV DNA - Nucleic Acid Amplification Test (NAT or NAAT) - Human herpesvirus 5 - Herpes -HHV-5 - Viral load monitoring

Guidelines

The CMV test is intended for use as an aid in the management of solid-organ transplant and hematopoietic stem-cell transplant patients who are undergoing anti-CMV therapy. This test can be used to measure serial CMV DNA levels and be used to assess virological response to antiviral treatment.

This test is not intended for use as a screening test for the presence of CMV in blood or blood products.

Collect

Plasma collected from lavender (EDTA) top tubes.

Handling

Separate plasma from whole blood within 36 hours of collection if stored at refrigeration or within 24 hours of collection if stored at room temperature.
Transfer 3.0 mL plasma into plastic aliquot tube and freeze immediately.

Preferred Volume

3.0 mL

Minimum Volume

1.5 mL

Transport

Frozen

Rejection Criteria

Heparinized specimens, specimens past stability, specimens with inadequate volume for testing or specimens tested in non-molecular labs.

Stability

On cells: Ambient: 24 hours; Refrigerated: 36 hours
After separation from cells: Ambient: Unacceptable; Refrigerated: 7 days; Frozen: 6 weeks

Note

Critical sterile. Specimens cannot be shared with other laboratory departments unless molecular testing is performed first.

Performed

Mon - Fri, batched two times per week.

Reported

2-5 days

Method

Method: Quantitative Polymerase Chain Reaction

Clinical Specificity: 100% with a confidence limit of 98.3% (A total of 227 samples were tested)

Analytical Specificity: No cross reactivity was observed in samples spiked with other common pathogenic viruses, bacteria, or yeast

Limit of Detection: 91 IU/mL

Quantitative Range: 137 – 9,100,000 IU/mL

(2.1 – 7.0 Log IU/mL)

1 IU/mL of CMV DNA is approximately 1.1 copies/mL

A negative result (“Not Detected”) does not rule out the presence of CMV below the limit of detection of the assay or the presence of inhibitory substances. CMV viral loads detected at less than 137 IU/mL are not quantitated. Assay is the FDA approved Roche AmpliPrep/COBAS®TaqMan® CMV Test.

Reference Values

Not detected.

Comments

Though rare, mutations in the highly conserved regions of the viral genome covered by the COBAS® AmpliPrep/COBAS® TaqMan CMV Test primers and/or probes may result in under-quantification of or failure to detect the virus.

Due to inherent differences between quantitative methodologies, it is recommended that prior to changing methodologies a new baseline is established before making clinical decisions.

CPT Codes

87497

CYTOMEGALOVIRUS QUANTITATIVE BY PCR

Specimen Collection Requirements

Testing Information

Reference Values