HBV, HCV & HIV-1 Triplex NAT for Blood Screening on the Pre-NAT II System
A Fully Automated Molecular Screening Solution for Blood Banks and Clinical Laboratories
Viral hepatitis B, viral hepatitis C and acquired immunodeficiency syndrome (AIDS) are caused by the hepatitis B virus (HBV), the hepatitis C virus (HCV) and the human immunodeficiency virus (HIV), respectively. HBV and HCV are both contagious viral infections that primarily damage the liver, causing acute or chronic disease in humans; when the infection persists, it can progress to cirrhosis and even hepatocellular carcinoma. HIV, by contrast, mainly attacks the CD4+ T lymphocytes of the human immune system and weakens immune defence, reducing the body's ability to resist bacteria, viruses and other pathogens. As a result, people living with HIV become susceptible to a wide range of diseases, and severe cases ultimately lead to death [1].
All three bloodborne viruses can be transmitted through blood and from mother to child. They can also spread through sexual contact with an infected partner, exposure to other body fluids, unsafe injections, or contact with contaminated sharp instruments [1].
Epidemiology: A Global and National Public-Health Challenge
According to statistics from the World Health Organization (WHO), more than one million people die from liver disease every year worldwide. Viral hepatitis is one of the leading causes of the global disease burden and remains a major public-health challenge in China [2]. Data published in 2020 in the Chinese Journal of Cancer Research show that infection with HBV and HCV is still the most important cause of liver cancer in the country: chronic viral hepatitis accounts for approximately 380,000 deaths each year, mainly through hepatitis-related cirrhosis and hepatocellular carcinoma.
HIV, meanwhile, remains a major global public-health problem for which there is still no cure. The virus continues to spread in countries around the world and has so far claimed the lives of 40.43 million people; by the end of 2022, an estimated 39.0 million to 45.7 million people were living with HIV [3]. In mainland China, 1.224 million people living with HIV have been reported and are still alive. Nearly 39% of newly diagnosed patients already have advanced disease, defined by a CD4+ count below 200 cells/µL, and HIV drug resistance among untreated people has been rising year by year. Together, these trends place a considerable burden on China's health-care system and on clinical management of the disease.
What Blood Screening Means in Practice
Blood screening, also referred to as blood-source screening, protects the safety of clinical blood and the quality of blood products, and prevents plasma that is positive for bloodborne pathogens from being transfused directly into patients or used in the manufacture of blood products. For this reason, screening is applied to blood donors and to plasmapheresis donors alike.
Because blood-screening reagents have a direct bearing on public health, they are strictly regulated. In addition to quality control throughout the entire production process, batch-release management is applied to every lot, further safeguarding reagent quality and reducing the number of infections transmitted through blood transfusion.
Expert Consensus and Guidelines: Who Should Be Screened
The Expert Consensus on Nucleic Acid Testing Strategies for Hepatitis B Virus, Hepatitis C Virus and Human Immunodeficiency Virus (Types 1 and 2) in Medical Institutions recommends triplex nucleic acid screening and detection for the following populations [4]:
- Patients before transfusion, especially those who frequently receive blood transfusions.
- Patients before surgery and those undergoing invasive examinations and invasive treatments.
- Patients on hemodialysis.
- Organ transplant donors and recipients.
- Patients with fever of unknown origin.
- Immunocompromised patients.
- Patients receiving anti-tumor therapy.
- High-risk patients with relevant epidemiological characteristics, as well as any other population in whom pathogen screening is clinically warranted.
Serology Paired with Nucleic Acid Testing
Blood-screening reagents fall into two broad categories: serological assays and nucleic acid testing (NAT). The Technical Operation Procedures for Blood Stations (2019 edition) have refined the testing strategy, requiring that blood-source testing apply serological reagents while also performing one round of nucleic acid testing.
The VirtueDx Hepatitis B Virus, Hepatitis C Virus and Human Immunodeficiency Virus (Type 1) Nucleic Acid Detection Kit (PCR-Fluorescence) combines high throughput, high sensitivity and a high degree of automation. When nucleic acid screening is performed before surgery or before transfusion, it complements serology and minimises the risk of missed infections caused by the serological window period, immunologically silent infection and other limitations of antigen- and antibody-based testing.
The assay supports bloodborne-infection screening before general surgery, before endoscopy and other invasive examinations, before cardiac interventional procedures, and before other invasive treatments such as dental procedures. In this way, it covers a wide range of clinical departments.
The Pre-NAT II Fully Automated Nucleic Acid Extraction System
The VirtueDx triplex reagent is designed around the Pre-NAT II fully automated solution. Focused on the blood-screening segment, the system provides clinical departments, blood banks at every level and other laboratories with timely, reliable screening results.
High Throughput
HBV, HCV and HIV-1 are detected from a single tube in one run, improving detection efficiency while lowering testing cost and shortening time to result.
High Sensitivity
The assay is engineered for high analytical sensitivity, supporting early detection of HBV, HCV and HIV-1 nucleic acid and helping to close the gap left by the serological window period.
Fully Automated Platform
Based on the Pre-NAT II automated solution, the workflow covers the complete process from nucleic acid extraction of primary-tube samples to assembly of the PCR reaction system, reducing manual handling errors and improving assay precision.
Accurate Interpretation
A dual internal-control system using both DNA and RNA controls monitors the effectiveness of nucleic acid extraction and PCR amplification, helping to prevent false-negative results.
Contamination Prevention
Unique self-rotating magnetic-rod mixing combined with a UNG-dUTP system provides two layers of protection against contamination by PCR amplification products.
References
[1] WHO. Global Progress Report on HIV, Viral Hepatitis and Sexually Transmitted Infections, 2021. World Health Organization, 2021. Available at: https://www.who.int/publications/i/item/9789240027077.
[2] Wang XJ, Zhang RZ, Hu YS, et al. Study on the epidemiological status of viral hepatitis in China [dissertation]. 2004.
[3] Rouzioux C, Hubert JB, Burgard M, et al. Early levels of HIV-1 DNA in peripheral blood mononuclear cells are predictive of disease progression independently of HIV-1 RNA levels and CD4+ T cell counts. J Infect Dis. 2005;192(1):46-55. DOI: 10.1086/430610.
[4] Blood Transfusion Physicians Branch, Chinese Medical Doctor Association. Expert consensus on nucleic acid testing strategies for hepatitis B virus, hepatitis C virus and human immunodeficiency virus (types 1 and 2) in medical institutions. Clinical Transfusion and Laboratory Medicine. 2020;22(6):561.
