Screening and diagnosis of HCV
Because acute HCV infection is usually asymptomatic, few people are diagnosed during the acute phase. In those people who go on to develop chronic HCV infection, the infection often remains undiagnosed because it often remains asymptomatic until symptoms develop secondary to serious liver damage.
Because acute HCV infection is usually asymptomatic, few people are diagnosed during the acute phase. In those people who go on to develop chronic HCV infection, the infection often remains undiagnosed because it often remains asymptomatic until symptoms develop secondary to serious liver damage which often occurs decades after virus enters the body.
Incubation period, symptoms and factors affecting progression of liver disease
- Incubation period 2 - 24 weeks
- 80 % do not show any symptoms
- Symptoms: fever, fatigue, decreased appetite, nausea, abdominal pain, dark urine,
- Joint pain and yellowing of skin and the whites of eyes
- Irus load do not correlate to the liver damage
- External and host factors that can increase the progression of liver disease:
- male gender;
- age of the time of infection 40 years;
- alcohol consumption 20g / day (one pint of beer);
- co - infection with HIV or hepatitis B - virus.
HCV infection is diagnosed in two steps
- Screening for HCV antibodies with a serological test identifies people who have been infected with the virus. HCV antibodies develop within 6 months (usually in 4 months.) The antibodies can be detected by rapid tests using a drop of blood, serum or month plaque or through a standard venous blood test.
- If the test is positive for HCV antibodies, a nucleic acid test for HCV ribonucleic acid (RNA) is needed to confirm chronic infection because about 15–45% of people infected with HCV spontaneously clear the infection through a strong immune response and therefore do not require treatment. Although no longer infected, they will still test positive for anti-HCV antibodies. This means that a person who was cured of HCV will have HCV antibodies in the blood forever, screening for HCV antibodies should be followed up with nucleic acid tests for HCV for those who are test positive for HCV antibodies.
After a person has been diagnosed with chronic hepatitis C infection, they should have an assessment of the degree of liver damage (fibrosis and cirrhosis) they may have. This can be done by liver biopsy or through a variety of non-invasive tests (e.g. Fibroscan or APRI index). In addition, these people should have a laboratory test to identify the genotype of the strain of HCV that they have. HCV has six genotypes, labeled 1 through 6. There are also subtypes labeled with letters, for example, genotypes 1a and 1b. Most people are infected by a single, dominant genotype, but it is possible to have more than one at the same time (called a mixed infection).
All persons with chronic HCV infection should undergo treatment with direct acting antivirals (DAAs). The degree of liver damage and virus genotype are used to guide treatment decisions and management of the disease. With the new pangenotypic DAAs,