Monday, September 24, 2007
Medical Microbiology
Name of Test: Detection of antibody to Hepatitis C virus (anti-HCV)
Principle of Test: The Anti-HCV assay is a two-step immunoassay, using Chemiluminescent Microparticle Immunoassay (CMIA) technology for the qualitative detection of anti-HCV in human serum and plasma. In the first step, patient sample, HCV coated microparticles and assay diluent are combined. Anti-HCV that is present in the sample binds to the HCV coated microparticles. After washing, anti-human acridinium-labeled conjugate is added in the second step. After washing again, Pre-trigger and trigger solutions are added to the mixture. The resulting chemiluminescent reaction is measured in relative light unit. The amount of anti-HCV in the sample is proportional to the relative light unit measured.
Test Result with reference range: Specimens with cut-off values <1.00 are considered nonreactive by the Anti-HCV assay and need not be tested further.
Specimens with cut-off value >/= 1.00 are considered reactive by the Anti-HCV assay.
Clinical interpretation: A positive anti-HCV test provides evidence of exposure to HCV. Specific antibodies against HCV may not always be detectable in early acute disease because antibody production is usually not detected until 7 to 31 weeks after infection. However, antibody detection doesn't differentiate between acute, chronic or past HSV infection. For diagnostic purposes, anti-HCV result should be used together with patient history. If Anti-HCV results are inconsistent with clincial evidence, further test would have to performed. Additional information can be obtained by testing for viral RNA in serum by PCR. A positive HCV RNA test is suggestive of viral replication in the liver and can confirm a diagnosis of either acute or chronic infection.
Yong Yang (TG02)
0503196H
Principle of Test: The Anti-HCV assay is a two-step immunoassay, using Chemiluminescent Microparticle Immunoassay (CMIA) technology for the qualitative detection of anti-HCV in human serum and plasma. In the first step, patient sample, HCV coated microparticles and assay diluent are combined. Anti-HCV that is present in the sample binds to the HCV coated microparticles. After washing, anti-human acridinium-labeled conjugate is added in the second step. After washing again, Pre-trigger and trigger solutions are added to the mixture. The resulting chemiluminescent reaction is measured in relative light unit. The amount of anti-HCV in the sample is proportional to the relative light unit measured.
Test Result with reference range: Specimens with cut-off values <1.00 are considered nonreactive by the Anti-HCV assay and need not be tested further.
Specimens with cut-off value >/= 1.00 are considered reactive by the Anti-HCV assay.
Clinical interpretation: A positive anti-HCV test provides evidence of exposure to HCV. Specific antibodies against HCV may not always be detectable in early acute disease because antibody production is usually not detected until 7 to 31 weeks after infection. However, antibody detection doesn't differentiate between acute, chronic or past HSV infection. For diagnostic purposes, anti-HCV result should be used together with patient history. If Anti-HCV results are inconsistent with clincial evidence, further test would have to performed. Additional information can be obtained by testing for viral RNA in serum by PCR. A positive HCV RNA test is suggestive of viral replication in the liver and can confirm a diagnosis of either acute or chronic infection.
Yong Yang (TG02)
0503196H
# posted by Star team @ 9:41 PM 
Comments:
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Hello!
So does that mean that a positive HCV RNA test signify a chronic infection?
Thanks!
Charmaint Tan
TG01
So does that mean that a positive HCV RNA test signify a chronic infection?
Thanks!
Charmaint Tan
TG01
To Eugene,
The pre-trigger and trigger solutions are actually the substrates for the enzyme-linked conjugate antibody.
To Charmaine,
Chronic hepatitis is characterized by a long and initially frequent asymptomatic course accompanied with fluctuating transaminase levels (ALT), which exceeds 6 months. Thus, HCV RNA will be detected if the infection remains.
To Elaine,
The anti-HCV markers the assay detects are IgM and IgG. The test is requested during hepatitis screening or for diagnosis purposes.
To Ching Wei,
The enzyme-linked conjugate antibody will convert substrate into coloured reaction. The resulting chemiluminescent reaction is measured in relative light unit. The amount of anti-HCV in the sample is proportional to the relative light unit measured.
Yong Yang
TG02
Post a Comment
The pre-trigger and trigger solutions are actually the substrates for the enzyme-linked conjugate antibody.
To Charmaine,
Chronic hepatitis is characterized by a long and initially frequent asymptomatic course accompanied with fluctuating transaminase levels (ALT), which exceeds 6 months. Thus, HCV RNA will be detected if the infection remains.
To Elaine,
The anti-HCV markers the assay detects are IgM and IgG. The test is requested during hepatitis screening or for diagnosis purposes.
To Ching Wei,
The enzyme-linked conjugate antibody will convert substrate into coloured reaction. The resulting chemiluminescent reaction is measured in relative light unit. The amount of anti-HCV in the sample is proportional to the relative light unit measured.
Yong Yang
TG02
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