PCR analysis for hepatitis C

WHO estimates that in 2020 there were over 1,5 million new cases of hepatitis C virus (HCV) or blood-borne hepatotropic RNA virus infection worldwide. The main modes of transmission of the virus include injecting drug use, unsafe injection practices, blood transfusions, and the reuse or insufficient sterilization of medical equipment, such as syringes and needles, in healthcare settings. Hepatitis C is not transmitted through breast milk, food, water, or casual contact such as hugging, kissing, or sharing food and drink with an infected person. The virus causes chronic hepatitis in about 80% of those infected. Many studies have been conducted in people with suspected hepatitis. Hepatitis C virus antigens were detected in the cerebrospinal fluid of 8 out of 13 patients with HCV, and there are reports of cases where the hepatitis C virus can be transferred to the brain.

Hepatitis C virus is a hepatotropic virus that is a major cause of liver disease and a potential cause of significant morbidity and mortality worldwide. The virus causes acute hepatitis, which is mostly subclinical but gradually develops into chronic hepatitis in about 80% of those infected. People infected with HCV are at risk of developing chronic liver disease, cirrhosis, and primary hepatocellular carcinoma.

Screening of all individuals with risk factors for HCV infection for anti-HCV antibodies (anti-HCV) or, in certain situations, by polymerase chain reaction is recommended. It is possible to identify the disease in the early stages with timely examination and diagnosis by PCR for hepatitis C.

What is PCR for hepatitis

The polymerase chain reaction (PCR) method is performed to detect the pathogen. Hepatitis C diagnostic tests can be divided into the following general categories: serological tests that detect antibodies to the hepatitis C virus; molecular assays that detect and quantify or characterize the genomes of a virus in an infected patient.

Serologic tests were divided into screening tests for anti-HCV (enzyme-linked immunosorbent assay) and additional tests such as recombinant immunoblotting. Three generations of PCR assays have been developed, and each has resulted in an improvement in HCV detection sensitivity.

The most common blood test is for the presence of antibodies to HCV. The detection of even low levels of antibodies indicates that the patient is a carrier of the hepatitis virus, since this indicator is zero in healthy uninfected people.

How is the procedure performed

The procedure is carried out by taking venous blood in the laboratory. Preparation for the analysis is not difficult. Blood is taken on an empty stomach under sterile conditions, as there are cases when the virus is introduced when sanitary conditions are not observed or when gloves are reused.

Further, the analyzes are sent for testing and after 1-2 days the results of the analysis are ready. In some cases, an additional blood sample is taken a few days later to accurately confirm the presence or absence of virus RNA.

Molecular virological methods play a key role in the diagnosis and monitoring of HCV treatment. Since growing a virus in a cell requires specific conditions, molecular methods help to detect the virus, making it one of the first pathogens identified by purely molecular methods.

Nucleic acid amplification technology (NAT) assay, an international standard method, is considered the “gold standard” for detecting active HCV replication. It is extremely effective in diagnosing acute infection because RNA is detectable as early as 1 week after possible infection and at least 4-6 weeks before seroconversion. Diagnosis of infection is established by antibody screening followed by NAT for HCV RNA for confirmation as well as monitoring patients during treatment. Viral load assessment at baseline is also critical to determine viral response during therapy.

When should I get tested for hepatitis C by PCR?

PCR is performed when antibodies to the hepatitis virus are detected or hepatitis C is suspected. Sometimes it also happens that a person is already a carrier of hepatitis or even has an active form of this disease. Patients with chronic hepatitis C are likely to have significant changes in their physical and mental state, most commonly manifested as fatigue and depression, and the hepatitis C virus itself can affect brain function. There is a possibility of direct infection of the central nervous system.

There are several options for how the virus is transmitted, so you need to know them. If a patient has had similar situations in his life, it is worth checking for HCV by PCR.

The virus is transmitted from one person to another, mainly by the parenteral route. The main routes of transmission are:

• injecting drug use, use of non-sterile syringes;
• blood transfusion and injections;
• clinical diagnostic procedures (professional influences, such as operations, probing, some types of examinations);
• tattoo;
• spread of the infection through sexual contact.

Occupational, perinatal and sexual transmission is less active than transmission through the blood. Therefore, these methods are not considered major sources of new HCV infection, regardless of population or geographic area.

Screening for infection has several potential benefits. If infection is detected early, antiviral treatment may be offered during the course of the disease, which is more effective early than late.

In addition, early detection, together with recommendations and lifestyle modifications, can reduce the risk of transmission to others. The best approach to screening is to screen individuals who have risk factors. The most common way the virus is transmitted is through a blood transfusion.

The risk of infection of recipients during blood transfusion is too high. Until the beginning of the 21st century, blood transfusion resulted in a high risk of infection, approximately 15-20%. In the 20th century, 90% of cases of post-transfusion hepatitis were caused by the same viruses.

Switching to blood sampling from volunteers instead of paid donors significantly reduced the risk of developing post-transfusion hepatitis (up to 10%). Blood screening further reduced the possibility of post-transfusion hepatitis C by a factor of about 10 from the current rate of 000 per million transfusions. The few cases that are still occurring involve newly infected people donating blood before they have developed antibodies (window period) to the virus, which can take up to 1-6 weeks.

Efficacy of the procedure

Detection of the virus in patients by polymerase chain reaction (PCR) indicates the presence of active infection and is potentially useful in confirming the diagnosis and monitoring antiviral response to therapy.

Optimal PCR assays currently have a sensitivity of less than 100 copies of HCV RNA per milliliter of plasma or serum. The standardization and quality assurance of diagnostic laboratories performing HCV PCR remains an important issue for future research.

There are two main technologies for assessing HCV RNA levels or viral load. Quantitative PCR is the most sensitive criterion for determining hepatitis C viral load, while the branched chain DNA test appears to be the most accurate method.

The main limitations of current assays are inadequate dynamic range, high variability in PCR-based assays, and low sensitivity of the branched chain DNA assay. Molecular tests have also been developed to classify HCV into distinct genotypes.

The problem of professional blood donation and unsafe injection practices is a potential source of hepatitis C infection worldwide. All practitioners should understand how to establish or rule out a diagnosis of HCV infection and interpret tests correctly.

In the absence of a prophylactic or therapeutic vaccine, and post-exposure prophylaxis against the virus, HCV infection must be diagnosed to prevent infection and subsequent complications, including primary hepatocellular carcinoma.

However, a lot depends on the patient himself. If a person notices at least some suspicions of infection or feels certain symptoms (chronic fatigue, drowsiness, loss of strength), you should contact your doctor for a referral for a PCR test for hepatitis C.

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