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Cytomegalovirus DNA, Quantitative PCR
|Test Update Information||On 9/18/13, UCSF will change in the test method for cytomegalovirus (CMV) PCR due to discontinuation of the prior assay reagents.
While the two assays are similar, there are some differences providers should note:
1) The results will be listed in International Units per milliliter (IU/mL), which is similar in clinical interpretation to the previously reported units of copies/mL.
2) The lower limit for quantification will be 137 IU/mL rather than 1000 copies/mL. The new assay has a slightly improved limit of detection compared to the previous assay.
3) There is a bias between the test methods, with results by the new method on average 0.91 log IU/mL lower than the previous method. Contact the Microbiology Laboratory (353-1268) to discuss re-establishing baseline CMV titers in patients with longstanding CMV infection.
Treatment of CMV infection should take into account the clinical presentation as well as the change in level of CMV DNA and not just the absolute level of DNA.
|Available Stat?||No, however, if the patient needs the result rapidly, contact the Virology lab at 415-353-4730 to make sure the sample is included in the next available run.|
|In House Availability||Test performed Monday - Friday day shift only|
|Method||Quantitative Real time PCR|
|Collection Instructions||Do not draw from heparin containing lines.
Note: If the patient needs the result rapidly, contact the Virology lab at 415-353-4730 to make sure the sample is included in the next available run.
|Container type||Lavender top|
|Amount to Collect||3 mL blood|
|Sample type||EDTA Plasma|
|Preferred volume||1.5 mL plasma|
|Min. Volume||1 mL plasma IMPORTANT: for samples between 0.5 and 1.0 mL forward sample to Microbiology for them to detrmine if it can be tested.|
|UCSF Rejection Criteria||Heparinized, grossly hemolyzed samples or repeat sample from a patient within 7 days.|
|Processing notes||Separate plasma from cells and freeze at -70C within 6 hours of collection.|
|Normal range||Not detected|
|Synonyms||CMV; PCR; CID; CMV inclusion disease|
|Stability||Room temperature 6 hours for whole blood, frozen at -70C indefinite.|
|Turn around times||Turnaround time 1-4 days|
|Additional information||This assay uses real-time PCR methodology to amplify a segment of the DNA polymerase (UL54) gene, and is capable of accurate quantification from 137 IU/mL to 9.10 x 10e8 IU/mL. Samples with DNA detected below the linear range will be reported as "Detected, < 137 IU/mL". Change in virus DNA level over time is a better indicator of clinical significance than absolute copy number.
The assay can reliably detect CMV DNA down to a lower limit of approximately 91 IU/mL.
This assay is most useful in monitoring patients at risk for development of CMV disease with end-organ manifestations (pneumonia, colitis, esophagitis, nephritis, chorioretinitis, encephalitis, polyradiculopathy, adrenalitis, hepatitis) or dissemination. Immunocompromised patients, including solid organ and hematopoietic stem cell transplant recipients and AIDS patients are at higher risk for clinical disease.
Changes in CMV viremia often parallel or precede end-organ clinical manifestations and can also be used to monitor treatment efficacy. Because different test methods can yield varying results, we recommend utilizing the same laboratory methodology to compare values.
|LDT or Mod FDA?||No|
|Last Updated||9/30/2013 11:37:02 AM|
If you have additional questions regarding this test, please call: 415-353-1667