Re: Weird hepatitis B test results

On Aug 20, 10:06 am, ri...@xxxxxxxxx (Rich Wales) wrote:
Robert1 wrote:

> Most cases are anicteric and people don't realize they
> have it. . . .

Given the timeline of evolution of HBV testing which you described,
would it be conceivable that I could have been exposed to HBV as a
child or young adult, and it might not have been detected with the
tests used by US blood banks during the 1970's and early 1980's?

Would tests commonly available in the US in 1992 (when I had various
tests as part of an application for Canadian immigration) have been
likely to detect either distant or not-so-distant exposure to HBV --
assuming for the sake of discussion that those tests did include a
test for hepatitis B, which might or might not have been the case?

All the technology was there including PCR for HBsAg first reported in
1975. HBeAg testing was also developed in 1976. The techniques were
different then compared to today. They were cumbersome and with a
higher to false positive rate.
Let me quote you from a text copyright 1984

"The primary laboratory tests for diagnosis are those designed to
detect HBsAg in the serum. These are used to detect active infections
as well as to screen potential blood donors. Of these,
immunodiffusion, counterimmunoelectrophoresis, complement fixation,
and radioimmunoassay have all been used."

Our current preference is to use either the RIA or EiA tests, which
appear to be of equal sensitivity. These tests will detect nearly all
cases of acute hepatitis B and most chronic carriers. It has been
suggested that adding an RIA or EIA test to detect anti-HBc will
enhance the sensitivity of detection. particularly for chronic
carriers."

All the technologies above were replaced by EIA technology and
available in the 1990s. The technology is also tied to clinical
utility and at present an acute hepatitis serology panel can be
reported out in 40 minutes compared to a week in the 1990s. The focus
of the acute hepatitis panel does not include total anti-HBc and so
you would test negative for everything based on that panel. In other
words one is looking for viral particles or serological evidence of
recent infection and not past infections. That's important for as to
the implication that blood banks were looking for viral particles
HBsAg testing in the 1970s along with doing liver enzymes in checking
for active hepatitis. As to the 1980s, the quote is contemporary above
and so one would guess based on the quote that HBAg testing was the
only test done and anti-HBc testing just coming into clinical utility.

With regards to immigration status one again looks at the context of
then and now. The current context is this 2006 advisory.

"Currently, hepatitis B and C testing are not required for the
immigration and refugee application process in Canada. However, the
prevalence of chronic hepatitis B infection in Asia, Africa, Eastern
Europe and Latin America is much higher than in Canada. In
asymptomatic individuals from high-prevalence regions, hepatitis B
screening should be undertaken for either hepatitis B surface antigen
carriage and the antibody to hepatitis B surface antigen (for
immunity) or the antibody to hepatitis B core antigen (for past
exposure to the virus). Further hepatitis B testing may be performed
depending on the results of the screening tests. Household and sexual
contacts of a hepatitis B carrier should be assessed. Those who have
not been exposed to hepatitis B or previously immunized should receive
a three-dose series of the hepatitis B vaccine (see Canadian
Immunization Guide"

It is unclear if any hepatitis testing was done in your case or which
test were done.


In short, assuming my known history is accurate as I described it
earlier, how likely is it that I might have been exposed to HBV a
long time ago, and it would never have been picked up on any tests
until my blood donation in 2001?

In the past the gold standard for hepatitis B was the HBsAg testing.
People were interested in detecting active viral particles in carrier
and in chronic hepatitis states for preventing transmission and for
diagnosing hepatitis B.

"Antibody to hepatitis B core antigen (anti-HBc) is an antibody that
generally appears close to the onset of clinical hepatitis and may
persist for years or life. In the mid-1980s, U.S. blood banks
voluntarily began anti-HBc screening of blood and blood components for
transfusion. This test was intended as a surrogate non-specific test
for hepatitis C (formerly called non-A, non-B hepatitis). In addition,
studies of transfusion-associated hepatitis B prior to anti-HBc
testing indicated that hepatitis B still occurred, despite the use of
a sensitive test for hepatitis B surface antigen (HBsAg)."

I don't know what they mean by surrogate test for hepatitis C. People
who were positive for anti-HBc and negative for HBsAg when transfused
into patients sometimes developed hepatitis. Was it hepatitis C or B?
They imply that is was hepatitis C I think.

http://www.fda.gov/cber/faq/bldfaq.htm#hbc

I am not a doctor and so I stay clear of making any type of implied
diagnosis or speculation on probabilities that are outside my
experience.
Of interest is the fact that there is no confirmatory testing of a
reactive anti-HBcore.

.

Relevant Pages

  • Re: Weird hepatitis B test results
    ... After donating blood in 2001, I was informed by the blood bank ... that my blood had tested "reactive" to the hepatitis B core ... anti-HBc twice, I would be permanently barred from giving blood. ... vaccination had worked and that I am now immune. ...
    (sci.med)
  • Weird hepatitis B test results
    ... After donating blood in 2001, I was informed by the blood bank ... that my blood had tested "reactive" to the hepatitis B core ... anti-HBc twice, I would be permanently barred from giving blood. ... vaccination had worked and that I am now immune. ...
    (sci.med)
  • Re: Anti-HBc
    ... "Anti-HBc appears at the onset of symptoms or liver test abnormalities ... acquired infection can be distinguished by the presence of the IgM ... which is detected at the onset of acute hepatitis B ... anti-HBs response after a 3-dose series of hepatitis B vaccine. ...
    (sci.med)
  • Re: Weird hepatitis B test results
    ... > In the past the gold standard for hepatitis B was the HBsAg ... before donating, it probably wouldn't have been noticed because ... that my anti-HBc results were truly genuine and not false positives. ... Source Plasma donors be tested for anti-HBc. ...
    (sci.med)
  • Re: Hepatitis B: Anti-HBc +, other HBV tests -
    ... HB surface antibody ... a test for the hepatitis C antibody was negative. ... Post vaccination titers would reveal a rapid rise of HBsAB denoting an ... The significance of 'anti-HBc only' in the clinical virology laboratory. ...
    (sci.med)
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