HEPATITIS C VIRUS (HCV)
Hepatitis C Virus serum/plasma test strip is a rapid chromatography immunoassay for the qualitative detection of antibody to Hepatitis C Virus in the serum or plasma. Hepatitis C Virus is an RNA virus, which is very effective viral pathogen. HCV has six major genotypes (subtypes): 1a, 1b, 2a, 2b, 3, 4, 5 and 6. Genotype 1a and 1b, which are the most common and more difficult to treat.
HCV virus happens despite a healthy immune system. It enters the body through direct blood exposure. The virus attacks cells in the liver, where it multiplies (replicates). HCV causes liver inflammation and kills liver cells. As many as 80-85% of people initially infected with HCV may become chronically infected that is, the infection does not clear up within six months. Most people with chronic HCV do not have symptoms. Today HCV is major problem for liver transplants. In 10-25% of people with chronic HCV, the disease progresses over a period of 10-40 years, and may lead to serious liver damage, cirrhosis and liver cancer.
Hepatitis C Virus Principle
HCV serum or plasma test is a rapid immunochromatographic direct binding test for visual detection of hepatitis C virus antibodies in serum or plasma samples in the diagnosis of hepatitis C infection. This HCV test adopts double antigen sandwich method.
When the test device is immersed into the specimen, the specimen is absorbed into the device by capillary action, mixes with the antigen-dye conjugate and flows across the pre-coated membrane.
When the HCV antibody levels are at or above the target cut off, HCV antibodies in the specimen binds to the antigen dye conjugate and are captured by antigen immobilized in the test region (T) of the device. This produces a colored test band and indicates a positive result.
When the HCV antibody levels are zero or below the target cut off (the detection sensitivity of the test). There is not a visible colored band in the test region (T) of the device. This indicates a negative result.
To serve as a procedure control, a colored line will appear at the control region (C), if the test has been performed properly.
Specimen Collection and Preparation in Hepatitis C Virus
- Separate the serum or plasma from blood as soon as possible to avoid haemolysis. Only clear, non-haemolysed specimens can be used.
- Test should be performed immediately after the specimens have been collected. Do not leave the specimens at room temperature for prolonged periods. Specimens may be stored at 2oC-8oC for up to 3 days. For long term storage, specimens should be kept below 2o
- Bring specimens to room temperature (10oC-30oC) before testing. Frozen specimens must be completely thawed and mixed well prior to testing. Specimen should not be frozen and thawed repeatedly.
Test Procedure for Hepatitis C Virus
The test strip and specimen have to be at room temperature (10oC-30oc) prior to testing.
- Remove the test strip from the foil pouch by tearing at the notch and place it on a level surface.
- Immerse the strip into the specimen with the arrow pointing towards the specimen. Take the strip out after 10 seconds and lay the strip flat on a clean dry non absorbent surface (such as the mouth of the specimen container).
- Read results in 15 minutes.
Interpretation of Positive (+)
Rose-pink bands are visible in both the control region and the appropriate test region. It indicates a positive result for HCV antibodies in the specimen.
Interpretation of Negative (-)
A rose-pink band visible in the control region. No colour band appears in the appropriate test region. It indicates that the concentration of the HCV antibodies of specimen is zero or below the detection limit of the test.
Interpretation of Invalid Result
No visible band at all or there is a visible band only in the test region and not in the control region. Repeat with a new test kit. If the test still fails. It means the strip is bad and needed to be changed.