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CSL Behring has engaged an external laboratory to perform parvovirus B19 nucleic acid testing (NAT) on all donations as part of plasma quality assurance release testing.
In the event a patient has received a blood component subsequently tested as positive for parvovirus B19 DNA, Lifeblood will notify the patient’s treating clinician.
Viraemia is seen approximately one week after exposure. Initial high-level viraemia usually occurs, followed by low levels that can persist for months to years.
As the initial phase includes very high levels of virus, often followed by persistent low-level viraemia, parvovirus B19 is considered a transfusion-transmissible pathogen. Despite the reported relatively common presence of parvovirus B19V DNA in healthy blood donors, the available evidence shows parvovirus B19 is not readily transmitted by transfusion. This may be due to several factors:
- Most donors with persistent infection have concomitant neutralising antibodies;
- High levels of immunity in recipients (approximately 80% in those aged 50 years old);
- Under recognition of transmission due to asymptomatic infection or non-specific symptoms; and
- Transmission does not occur unless viral loads are high. Viral loads 105 IU/mL are generally considered above the threshold where transmission might occur, which is the level of detection set for the testing.
Those most at risk of serious complications include individuals with bone marrow issues, such as thalassaemia, and fetuses through transplacental transmission.
The majority of parvovirus B19 infections are either asymptomatic or cause non-specific flu-like symptoms and do not generally cause serious disease. The most common clinical manifestations in adults are arthralgia and moderate to severe polyarthritis. Infection through blood transfusion is not expected to result in respiratory symptoms.
Parvovirus B19 infection in non-immune pregnant women may lead to virus transmission to the fetus, with the most common complication being hydrops fetalis due to an aplastic crisis where erythrocytes have a reduced life span. The risk to the fetus is highest in the first and second trimesters. Other adverse clinical outcomes associated with parvovirus B19 infection include transient aplastic crisis/haemolytic crises in patients with underlying haemolytic anaemia and chronic anaemia in immunocompromised patients.
Recommended testing for recipients
| Population | Recommended testing |
| No risk factor/s identified for complicated disease (i.e. does not belong to group below) | Further testing not recommended. If your patient develops symptoms consistent with a clinically compatible illness, consider serologic testing (IgM/IgG), and PCR if available, if clinically indicated for a diagnosis. If your patient has received IVIg or other blood products, passive transfer of antibodies may interfere with interpretation of serological results. |
| Patient has pre-existing bone marrow issues, is immunosuppressed or pregnant | Determine if the patient is at risk of transfusion-transmission by testing baseline serology, i.e., before the implicated transfusion. If IgG antibody positive before transfusion, consider the patient as immune and not at risk. Further testing may be indicated if symptoms develop (febrile illness, rash, red cell aplasia). If not immune, evaluate for potential transfusion-transmission with PCR and serology. Consider consulting a local infectious diseases physician or clinical microbiologist.
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Treating clinicians should seek local infectious diseases physician or clinical microbiologist support.
If test results suggest transfusion-transmission, or there is an adverse outcome, report to Lifeblood by email to LookbackNational@redcrossblood.org.au.
Updated June 2025
