CMV Viral Load

Testing Laboratory

Auckland Te Toka Tumai | Auckland Hospital

Department

Virology

Delphic Registration Code (Alpha Code)

CVLD

Test Code (Numeric Code)

8024

Laboratory Handling

Phlebotomy

A dedicated specimen (i.e. no other tests to be performed) is required for this assay. PPT tube is preferred, EDTA whole blood is acceptable.

Registration

If an FBC and Molecular testing are both requested and only one EDTA tube is received, send the specimen for FBC testing and forward a “Query Correct Specimen” form to VIM. If both a micro EDTA specimen and a full EDTA tube are received for FBC and Molecular testing, send the micro EDTA specimen for FBC testing and the full EDTA tube for Molecular testing.

Separating

PPT tube must be centrifuged and the plasma separated within 6 hours of collection.

Laboratory

EDTA whole blood and centrifuged PPT tubes should be sent to the Molecular Infectious Diseases section during normal working hours, Monday to Friday (08:00–16:00). After hours and on weekends, store specimens at 2–8°C in the designated box/rack in ALSS.

Sample Stability

EDTA whole blood: Stable at room temperature for up to 24 hours and at 2–8°C for up to 7 days. PPT: Tubes must be centrifuged and plasma separated within 6 hours of collection. Separated plasma is stable at 2–8°C for up to 7 days.PPT tubes Must be centrifuged and plasma separated within 6 hours of collection. Separated plasma and Urine is stable at 2–8°C for up to 7 days. If storage exceeds 7 days, aliquot the plasma and serum into appropriately labelled secondary tubes and freeze at ≤−20°C.

Associated Tests

• CMV PCR
• CMV Drug Resistance

Synonyms

CMV Viral Load
Cytomegalovirus Viral Load
Cytomegalovirus Quantitative PCR

Turnaround Time

3 days

Test performed three times weekly: Monday, Wednesday and Friday. Test is not performed on weekends.

Specimen Type

• Plasma
• Urine

Specimen Requirements

Tube/Container Type:

Preferred

• PPT Plasma Preparation Tube (Pale Pink Cap)

Acceptable

• PPT Plasma Preparation Tube (Pale Pink Cap)

Preferred Sample Volume (ml)

1

Minimum Sample Volume (ml)

0.7

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Microtainer)
• Please refer to Additional Information below

Acceptable

• EDTA (Microtainer)
• Please refer to Additional Information below

Additional Specimen Information

Preferred specimen is plasma, but test can be performed on urine for children under 1 year for congenital CMV.
Plasma:1mL. Absolute minimum is 0.7 mL.
Micro EDTA blood. 1.5 mL
Urine: 1 mL

Aliquot Instructions

Sample Type

• Plasma
• Urine

Minimum Volume (ml)

0.7

Transport to Lab

Chilled (2 - 8 degrees Celsius)
Frozen

Additional Referral/Aliquot Information

Sample requirements:
PPT is the preferred specimen type. Plasma separated from EDTA whole blood, including EDTA Micro collect tubes, are acceptable.
PPT tube must be centrifuged and plasma separated within 6 hours of collection.
EDTA tubes must be centrifuged within 6 hours of collection and the plasma transferred to a separate sterile tube.
Submit a minimum of 1.0 mL of separated plasma.
Urine: 1 mL - For children under 1 year for congenital CMV
Sample stability:
PPT tube must be centrifuged and plasma separated within 6 hours of collection. PPT tube with separated plasma is stable at 2–8°C for up to 7 days.
EDTA plasma: EDTA whole blood must be centrifuged and plasma transferred to a sterile secondary tube within 6 hours of collection. Separated plasma is stable at 2–8°C for up to 7 days.
If storage exceeds 7 days, separated plasma should be aliquoted and frozen at ≤−20°C.
Urine is s stable at 2–8°C for up to 7 days, If storage exceeds 7 days, separated plasma should be aliquoted and frozen at ≤−20°C.
Transport:
Transport separated plasma and urine chilled at 2–8°C if it will be received within 7 days of collection. If this period will be exceeded, transport the specimen frozen.

Test Method

Quantitative CMV viral load testing using the Roche cobas 6800 CMV assay

Limitations / Interference

The linear range of the assay is:

34.5–10,000,000 IU/mL (1.54–7.00 log IU/mL).
CMV viral load results are reported in IU/mL and log IU/mL.

Note: CMV viral load is reported in International Units (IU) and log IU. One IU equates to 1.09 viral copies.

Uncertainty of Measurement

+/- 0.01 log IU/ml

Urgent enquiries:
In normal working hours (08:00-16:00 Mon-Fri) contact Clinical Virology via LabLINK (internal extension 22000, external number 09 307 8995).
Outside of normal working hours (evenings and weekends) contact the On Call Clinical Microbiologist via Te Whatu Ora Te Toka Tumai Auckland main switchboard (09 367 0000).
Non-urgent enquiries:
Email: AK-MOL-INF-DIS@tewhatuora.govt.nz

Contact Information