Blood-borne infections
PCR diagnostics of blood-borne infections. Qualitative and quantitative assessment of hepatitis B and C viruses’ presence in patient’s blood.
PCR diagnostics of blood-borne infections
Blood-borne infections are infectious diseases whose pathogens can be transmitted through contact with the blood of an infected person. In a healthcare setting, transmission of such infections can occur through transfusion of blood and its components from an infected donor, or through breaches in aseptic technique and/or staff protection measures.
The foundation of transfusion safety lies in donor screening and testing for markers of viral infections. In the Russian Federation, serological screening of donor blood employs enzyme immunoassay (EIA) test systems for:
- Antigen (HBsAg) for hepatitis B virus (HBV);
- Antibodies for hepatitis C virus (HCV).
Serological methods can sometimes be ineffective in detecting blood-borne infections, primarily due to the serological window – the period from the entry of an infectious agent into the human body until the formation of specific antibodies. This creates the possibility of accepting an infected donor and increases the residual risk of infection via blood transfusion. Hepatitis C virus (HCV) poses the greatest challenge in this regard, as it is characterized by a high replication rate and delayed appearance of specific antibodies.
The application of PCR diagnostics helps shorten the seronegative window period for HBV and HCV, thereby reducing the risk of virus transmission through donor blood and its products.
HCV genotyping
Hepatitis C virus (HCV) is the primary etiological agent responsible for the spread of viral hepatitis. HCV is globally prevalent, with approximately 3% of the world’s population infected. HCV infection, along with hepatitis B virus (HBV) infection, is recognized as a leading cause of acute and chronic liver diseases, including cirrhosis and hepatocellular carcinoma (HCC). In 80% of cases, acute hepatitis progresses to a chronic form.
Currently, at least eight major HCV genotypes and over 100 subtypes are identified. Globally, genotype 1 is the most prevalent, followed by genotype 3. The distribution of HCV genotypes is geographically determined. In Russia, types 1b, 3a, and 1a are predominantly prevalent, while 2a, 2k, and 4 are significantly less common.
The course and efficacy of HCV infection treatment depend on the viral genotype. Genotypes 1b and 4a, known for their high replicative capacity, are the most dangerous. The detection of HCV in blood plasma and serum, followed by genotype identification, is crucial for clinical diagnostics, selection of antiviral therapy, ensuring blood safety, and providing epidemiological data on HCV prevalence.
The range of HCV RNA viral load can vary widely: from very low levels in samples from asymptomatic carriers and individuals in the convalescent stage to extremely high levels in samples from patients presenting with acute viral hepatitis.
HBV genotyping
For patients suspected of having acute viral hepatitis B, testing for hepatitis B virus DNA in blood by PCR (qualitative and quantitative) is recommended. This testing is effective for early diagnosis and establishing viral load levels.
Differences between viral genotypes have clinical significance and influence the efficacy of therapy. Certain genotypes, such as C and D, can contribute to more severe liver disease progression, including the development of cirrhosis and HCC. Furthermore, patients infected with genotypes A and B respond better to interferon-based therapy than those with genotypes C and D. Consequently, determining the pathogen’s genotype in patients with chronic HBV infection can assist clinicians in identifying individuals at risk for disease progression and prescribing optimal antiviral therapy.
Indications
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Confirmation of current infection -
Administration of antiviral therapy for chronic hepatitis C -
Monitoring treatment efficacy -
Liver disease of unspecified etiology -
Acquired immunodeficiency -
Use of immunosuppressive therapy
List of PCR studies
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HBV
A test for PCR-based qualitative detection of hepatitis B virus (HBV) DNA in blood plasma samples.
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HCV Genotyping
Real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for detecting Hepatitis C virus RNA and genotyping; identifies the most common genotypes: 1a, 1b, 2 and 3a/3b.
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HCV
A PCR-based test for qualitative detection of Hepatitis C virus RNA in blood plasma samples; identifies the following HCV genotypes: 1a, 1b, 2, 3, 4, 5, 6.
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Please note that the specialists of the DNA Technology company provide consultations exclusively to medical specialists on the application and research features. Requests related to the appointment, delivery, or interpretation of tests are not considered. For relevant information, we recommend contacting the laboratory directly.