Specimen Collection

5 mL PPT Plasma (Preferred)

4 mL EDTA Plasma
Turnaround Time:

Assay performed on request. Minimum turnaround time is one week.

Assay Method

The assay involves amplification and sequencing selected regions of two CMV genes, phosphotransferase (UL97) and DNA Polymerase (UL54). Mutations in these genes account for the majority of resistance seen to ganciclovir (GCV), cidofovir and foscarnet (PFA).

Diagnostic Use and Interpretation

Diagnostic Use

CMV resistance to antiviral drugs occurs most frequently in patients on prolonged antiviral therapy and is particularly associated with prolonged oral ganciclovir therapy. Thus HIV patients with CMV retinitis are at risk, also transplant patients receiving ganciclovir prophylaxis for CMV disease or prolong treatment due to CMV related problems.

Immunocompromised patients.

Patients with defects in cell-mediated immunity are more susceptible to CMV infection (solid organ transplant, haematopoietic stem cell transplant, HIV infected, recipients of chemotherapy, congenital immune deficiencies). CMV disease in immunocompromised patients may be due to primary infection, reactivation or re-infection. Symptoms vary in severity and site affected. Frequent manifestations include retinitis, colitis and pneumonitis, in addition to non-specific symptoms such as malaise, fever, myalgia, leukopenia, thrombocytopenia and mild hepatitis.

Congenital / Perinatal infection

Congenital CMV infection can occur as a result of maternal primary infection or reactivation. Congenital infections can have severe manifestations: intra-uterine growth retardation, jaundice, petechiae, myocarditis, pneumonitis, chorioretinitis, neurological symptoms and sequelae. Peri-partum infection can occur via exposure to the birth canal or breast milk. Urine and saliva are the most sensitive specimen types for the diagnosis of congenital / post-partum CMV in new-borns.

Immunocompetent

CMV infection in immunocompetent individuals is usually asymptomatic. Symptomatic infection in immunocompetent hosts manifests as a mononucleosis-like syndrome (prolonged fever, myalgia, atypical lymphocytosis, mild hepatitis), although can cause severe disease (colitis, meningoencephalitis, haemolytic anaemia, thrombocytopenia, arterial or venous thrombosis, ocular complications, hepatitis, pneumonitis

References

1. 2006 Red Book. Report of the Committee on Infectious Diseases 274 ^th Edition. Published by American Academy of Paediatrics.

2. Boppana SB, Ross SA, Shimamura M et al. Saliva Polymerase-Chain-Reaction Assay for Cytomegalovirus Screening in Newborns. NEJM 2011;364:2111-8

3. Ross SA, Ahmed A, Palmer AL et al. Detection of Congenital Cytomegalovirus Infection by Real-time Polymerase Chain Reaction Analysis of Saliva or Urine Specimens. JID 2014:10:1415-8

4. Revello MG, Zavattoni M, Furione M et al. Quantification of Human Cytomegalovirus DNA in Amniotic Fluid of Mothers of Congenitally Infected Fetuses. J Clin Microbiol. October 1999 vol. 37 no. 10 3350-3352

Contact Information

For further information contact the laboratory (contact via Lablink: 22000 or (09) 307-8995 or 0800 522 7587) ,or:
the Virology team virology@adhb.govt.nz

Specimen Transport Instructions for Referring Laboratories

1. Centrifuge PPT tube within 24 hours and send the spun tube to LabPLUS. Spun tubes can be stored at 4 ^o C over weekend.

2. Centrifuge EDTA tube within 24 hours of collection. Transfer the plasma to a new tube and send it to lab Plus. Avoid any contamination during separation.

Transport spun/separated tubes at 2 - 8 ^o C if transport time from collection is less than 72 hours. Transport frozen if more than 72 hours.

Last updated at 16:30:12 09/11/2022