Question
Confused about hepatitis C antibody tests…
2 March 2008. Related: All topics, Complications and coinfections, HIV testing, Opportunistic infections.
Hi guys wondered if you could help me?
The only thing I could find in your archives about this seemed to confuse me more to be honest so would really appreciate it if you could answer my question.
A while back I came in contact with a guy who was hiv/hep c coinfected, although I didn’t know this at the time and didn’t find this out till some time later. I had an HIV-1/2 antibody test and a hep C antibody test which both came back negative.
From time to time my worries flare up over this whole issue and stupidly I trawl the net for answers.
This time I came across something that seemed to suggest that when you come in contact with HIV/hep C coinfection you cannot have antibody tests for either HIV or hep C because they won’t pick either infection and that the only way to rule out HIV/hep C coinfection is to have a PCR test.
Could you throw some light on this for me pls, as you can imagine I am very troubled about this as I thought I was totally in the clear after my antibody tests.
Answer
HIV antibody tests are accurate whether or not you also have hepC.
As with HIV tests, HCV tests have a window period after infection when they are not accurate. For HIV the window period is 8-12 weeks, for HCV it is 6-24 weeks.
Both tests after these periods are accurate, irrespective of other infections.
The following information about hep C antibody tests is from our guide to HIV and hepatitis C coinfection.
Tests to diagnose hepatitis C
“Hepatitis C (HCV) testing is a two-stage process. The first test is usually an HCV antibody test. If it is positive, it means that you have been infected with hepatitis C in the past, and that you may still be infected. People who have spontaneously cleared hepatitis C without treatment remain antibody-positive for years afterwards.
On the other hand, antibody test results may be negative even when someone does have chronic hepatitis C. This may occur when:
– CD4 cell count is low (less than 200), because the immune system may not be producing antibodies.
– In acute (early) HCV infection, since antibodies take six to twenty-four weeks after infection before they develop.
An HCV viral load test (RNA) will confirm or rule out chronic infection. The viral load test looks for genetic material of HCV in the same way as an HIV viral load test detects HIV.
If you have detectable HCV viral load, it means that you are currently infected with HCV. If your hepatitis C viral load is undetectable, a second test should be done six months later. If two successive test results are undetectable, you have cleared HCV.”