Most ELISA tests in current use are very sensitive at
picking up antibodies to the hepatitis C virus, but they also have
a high rate of false positivity (cases where the test appears
positive but the patient is NOT really infected). To be certain
that a positive test is truly positive, most testing sites do
further testing (called RIBA or Recombinant ImmunoBlot Assay) on
all positive sera. A test is reported as positive only if it is
confirmed by the RIBA assay. In RIBA testing, recombinant HCV
antigens are applied separately onto special paper strips and used
to detect the presence and specificity of antibody present in the
test serum. Typically, a RIBA test is called positive, confirming
HCV infection, if two or more HCV antigens are detected. Third
generation ELISA tests are becoming available which are highly
specific (99%) for HCV; they are not yet FDA Licensed, Despite the
high sensitivity of second generation ELISA tests, antibody
production by an infected individual may take up to 3 to 4 months
(rarely up to 6 months) to develop. Hence, there remains a "window
period" during which the individual is infected but without
detectable antibody. Immunosuppressed patients (renal transplant,
those on steroids, HIV patients) may also have active HCV infection
without detectable antibody.
The original test used to screen you (ELISA) detected antibody
to HCV. This antibody is a marker of HCV infection at some time in
the past which caused you to produce the antibody in the first
place to fight off the original episode of infection.
The test result is normally confirmed by carring out another
form of test for antibody called RIBA. The original test simply
says you have antibody. The RIBA is capable of showing that you
have different types of antibody directed against different
proteins from the virus and thereby more specifically confirms the
original result.
However, antibody only tells about YOUR body's immune response
to the virus and tells nothing about the response of the virus to
you.
Did it survive from the original infection or was it eliminated?
If if survived and is still in you liver is it active? Is so how
active?
These and other questions can be resolved by looking for the
virus itself. PCR is a test that looks for viral genetic material
in your circulating peripheral blood supply. If it is found ( a
positive PCR result) then the virus is still active and producing
new viral material. IF positive the amount can be qnantitated to
see how much viral genetic material is present, from this the level
of activity of the virus can be deduced (the more viral genetic
material, the stronger the PCR result, the more active the
virus).
Only the lab that carried out the PCR can tell you accurately
what your value means. This is because PCR results carried out at
different sites can vary due to the way that the individual lab
carried out the test.
NOTE: Even if the virus is not circulating in your blood and
measurable/detectable by PCR, it often is still lurking in the
cells of your body and may return to the blood and the
liver.
The links below will take you to more research information
Liver
Function Tests A comprehensive article is located http://worldmall.com/erf/lectures/lvr-test.txt
How To
Understand Your SMAC Blood Test Report
Common
diagnostic tests used in Hepatitis
Clinical
Approach to the Patient with Abnormal Liver Test Results
Drugs That
May Cause Liver Dysfunction or Damage
Liver
& Drug Interaction
Amoxicillin-Clavulanic
Acid: Higher Risk Of Hepatotoxicity Than With Amoxicillin
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