Current Issue

EBV PCR Sample Source: Blood or Plasma?

Matthew Sekedat, Ph.D
Scientific Director, Virology and Molecular Biology  


In February 2020, Warde Medical Laboratory will update its sample requirements for EBV DNA testing.


Epstein-Barr Virus (EBV) is an extremely common double-stranded DNA virus in the Herpesviridae family. Multiple studies suggest that 90-95% of adults ≥35 years are EBV seropositive indicating a prior infection. EBV infections in children are often asymptomatic and symptoms in teenagers and adults are usually mild and resolve within a few weeks. Latent virus can reactivate later in life but most healthy adults will remain asymptomatic during a secondary infection (1).

Unfortunately, the near ubiquitous presence of EBV puts immune-compromised patients at risk for serious complications. Patients on immunosuppressive drugs after a solid organ or hematopoietic stem cell transplant are particularly susceptible to EBV-associated post-transplant lymphoproliferative disease (PTLD) (2). EBV may be responsible for up to 50% of PTLD cases overall (3).

Real-time DNA PCR assays that indicate the presence/absence and viral load of EBV can improve outcomes for transplant recipients. Increasing EBV viral loads correspond to an increased risk for PTLD and may indicate preemptive therapy, including reducing immunosuppressive therapy or administering antiviral drugs.

Changes to the Test

To help providers monitor EBV infections, Warde began offering real-time PCR for qualitative and quantitative EBV testing in-house on September 25, 2019 (test codes EBQL and EBVQN, respectively). These in-house tests are validated for frozen plasma and we send out other sample types, including whole blood (PBMCs), cerebrospinal fluid (CSF), and bone marrow.

Beginning February 2020 Warde will no longer accept whole blood as a sample type for EBV testing. We will continue to offer EBV DNA testing on frozen plasma, CSF, and bone marrow.

We pride ourselves on providing the most reliable results for all tests on our menu. This change aligns our testing with multiple studies indicating that cell-free EBV DNA in plasma has higher clinical specificity and sensitivity when compared with EBV in PBMCs4-6. These data are rightly changing the standard EBV source sample from whole blood to plasma at many labs and we strongly encourage providers to send frozen plasma. In-house EBV plasma testing is generally faster than other sample types, which will be sent to a partner lab.

There is additional information on our website on acceptable sample types. Warde also offers a number of tests in-house for monitoring viral reactivation that can be associated with immunosuppressive treatment (VZV, CMV, polyoma BK virus, HSV-1/2, HBV, HCV, and respiratory virus panel). Please contact the Warde Client Services line at (800) 760-9969 with any further questions regarding this change.


  2. Dierickx D, et. al. Post-Transplantation Lymphoproliferative Disorders in Adults. N Engl J Med 2018; 378:549-562.
  3. Luskin MR, et. al. The impact of EBV status on Characteristics and Outcomes of Post-transplantation Lymphoproliferative Disorder. Am J Transplant 2015; 15:2665-2673.
  4. Lee TC, et. al. Quantitative EBV Viral Loads and Immunosuppression Alterations can Decrease PTLD Incidence in Pediatric Liver Transplant Recipients. Am J Transplant 2005; 5:2222-2228.
  5. Tsai DE, et. al. EBV PCR in the Diagnosis and Monitoring of Posttransplant Lymphoproliferative Disorder: Results of a Two-Arm Prospective Trial. Am J Transplant 2008; 8:1016-1024.
  6. Kanakry J, et. al. The Clinical Significance of EBV DNA in the Plasma and Peripheral Blood Mononuclear Cells of Patients with or without EBV Diseases. Blood 2016; 127:2007-2017.