Thursday, April 25, 2013

Numerous Medical Tests For Hepatitis C Testing Los Angeles

By Mike J. Carter


At hepatitis C testing Los Angeles there are numerous medical tests which are currently available for the diagnosis of hepatitis C virus (HCV) infection. They can be categorized according to the way the tests are utilized. Screening tests are tests that are used to diagnose a condition or disease among individuals not known to have the disease. They are particularly useful for people who have risk factors for the condition or disease.

The first step in screening for HCV infection is to test blood for the antibody to HCV using an enzyme immuno-assays (EIAs). If the EIA test is negative (doesn't find the antibody), the patient is presumed to be clear of HCV. It takes several weeks up to six months for antibodies to develop after the initial infection with HCV, so this screening test may miss a few newly-infected individuals. The EIA screening tests are very specific; if the test is positive the probability of having HCV infection is greater than 99%.

Recombinant immunoblot assay (RIBA)is employed to verify the positive results of EIAs since at times a positive EIA is a false positive, that is, the test is positive when HCV isn't present. Even though the direct detection of HCV RNA (HCV PCR) is also widely used to verify the HCV infection, RIBA is still useful to distinguish false positive results in the few people whose immune systems have eradicated the virus but still have antibodies left over from the resolved infection. Several tests are available to measure the amount of HCV RNA in a person's blood. These tests are known as molecular tests since they examine the virus at the molecular level. A single negative test for RNA does not mean that there is no infection because the virus may appear in the blood intermittently or may exist in small amounts.

Testing for RNA is useful in determining whether or not a patient has circulating virus in the blood (viremia). Therefore, it can be utilized to verify that a positive EIA/ELISA really reflects active HCV infection. RNA testing also should be done in individuals who may have been recently exposed to HCV. HCV RNA testing is more sensitive than the conventional EIA testing in this setting. The reason for this greater sensitivity is that it may take a person several weeks after exposure to HCV to develop the antibodies, whereas HCV RNA becomes detectable one to three weeks after exposure. Finally, HCV RNA testing may be helpful to assess a patient's response to treatment at certain time points during antiviral therapy.

Blood tests as hepatitis C testing Los Angeles also have been developed to identify the HCV genotype. Blood tests can inform the clinician whether HCV is present but cannot tell the level of liver damage that has transpired. Liver biopsy enables the clinician to determine how much inflammation and scarring is present by examining a small sample of liver tissue. Liver biopsy provides information useful in the decision to start therapy. Considerable liver damage is a risk factor for other conditions like hepatocellular carcinoma and esophageal varices. Liver biopsy may be recommended when the clinician is unsure about whether to begin treatment or wishes to monitor the response within the liver to therapy.




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