HCV - blood test - what is it?
One of the most complex and common diseases of the end of the last century is infection with the hepatitis C virus. In developed countries, the prevalence of the disease reaches 2%, while the total number of patients worldwide is 500 million people. The infection was detected much later than its predecessors: hepatitis A and B - and at first it was called “neither A nor B infection”. Along with the growth of drug addiction, the number of infected is growing every year. The reason for all is the way of infection: with intravenous drug.
Also, the virus is transmitted during childbirth from mother to child if skin damage has occurred. Therefore, it is important to know, HCV blood test - what is it? During pregnancy, it is necessary to pass every future mother. This disease is a leader among the reasons that require transplantation to a sick liver.
How does hepatitis C develop?
Infection with the hepatitis C virus occurs as follows: the blood of a sick person must enter the blood of a healthy person.The first blood flow carries the virus particles, dissolved in healthy blood, into the liver and reproduction begins immediately. In this case, the human liver is doubly affected: on the one hand, the liver cells are damaged by the activity of the virus itself, on the other - the human body begins to fight: it sends immune reactions, namely, special lymphocyte cells that will be called upon to destroy the infected liver cells.
The virus recognizes the immune system according to the content of foreign genetic material. Anyone who has come across this, as well as some patients who are compulsory, know what the HCV blood test means. Everyone, at least once faced with this problem, will say that these are very important indicators both at the detection stage and at the treatment stage.
When are HCV tested?
When a patient has complaints of the liver, doctors usually prescribe a HBS and HCV blood test for such a patient. In order to determine whether the disease is caused by the presence of hepatitis C virus or other associated diseases in the blood, it is the HCV blood test that is needed. What is this indicator?
The analysis reveals antibodies in human blood that may belong to one of 2 classes:
- Antibodies to HCV. They are the main marker. The presence of infection in the body is confirmed by detection of HCV RNA. These antibodies are found at the stage of recovery and may also continue to be in the blood for 1-4 years. The main indicator of the presence of chronic hepatitis is the growing rates of anti-HCV.
- The level of IgA, IgM, IgG in serum. The growth of these markers indicates liver damage when exposed to alcohol, with billiard cirrhosis and some other diseases.
What are the markers talking about?
From the moment the antigen enters the human body as early as 4-5 weeks, it can be detected by an HCV blood test. That it is the hepatitis C virus that cannot be said with accuracy. These data are necessary for the doctor to make a decision about the need for such a patient antiviral therapy. Especially if less than 750 RNA copies per 1 ml of blood are detected in the blood, this indicates a minimal virus attack.
Hepatitis C antibodies always belong to one of two classes, G or M, which are required to add a blood test to HCV. Decryption explains these parameters as immunoglobulin class G (IgG) and M (IgM).A positive result on the first marker does not indicate a definite diagnosis. Class G immunoglobulin reaches its maximum performance at 5-6 months from the moment of infection in the body and remains the same in chronic hepatitis.
Immunoglobulins of the M class can be determined already in 1-1,5 months after infection and very quickly reach the maximum concentration. There is another indicator - anti-NS3, which, with its high performance, is a definite precursor of the presence of an acute process in the body.
How to donate blood for HCV analysis?
To donate blood in the laboratory to determine the presence of HCV antibodies, there are no specific instructions. The only recommendation of the doctors: the fence should be made on an empty stomach. Blood is taken from the vein of the patient being tested using a disposable syringe.
Interpretation of indicators
So, the alleged patient did a HCV blood test. What are these pluses and minuses as a result? The following table will answer this.
|Igm||Igg||NS IgG||HCV RNA||Presumptive diagnosis|
|+||+||-||+||Acute Hepatitis C|
|+||+||+||+||Chronic hepatitis C, reactivation phase|
|-||+||+||-||Chronic hepatitis C, latent phase|
|-||+||-||-||The stage of recovery of acute hepatitis C or the latent phase of chronic hepatitis C|
Types of HCV tests
There are qualitative and quantitative tests that determine HCV (blood test). What it is?
Quantitative tests are applied if the lower limit reaches 500 RNA copies per ml or 200 units per ml. These tests determine HCV-RNA. The measurements are carried out twice, as the data often differ. With positive anti-HCV and quantitative tests give a positive result in about 75% of cases. In addition, this result can be obtained in almost 95% of cases in patients with acute or chronic hepatitis C. Such tests are used in the diagnosis of acute infections, as well as in immunodeficient patients, whose antibody test gave a negative result, but there is a suspicion of HCV infection.
Qualitative tests are more sensitive, the lower limit is 100 RNA copies per ml. Used to establish the diagnosis of acute HCV infection, making a blood test for HCV. A positive result can be detected already during the first two weeks after infection. A quality test is different in that it can also give a false-positive or false-negative result.