|HB cAB results and exposure window
Jan 28, 2007
I donated blood two weeks ago and received a letter from the blood center that my HB sAG results were non-reactive but that the HB cAB results were positive (they don't test for HB sAB). The letter indicates that I may have been exposed to Hepatitis B and it has cleared my system or that the test may have been a false reactive. The epidemiologist said their tests are highly sensitive and that things such as stress or some medications might create a false reactive on the HB cAB. I looked over my records and I had taken Vicodin the night before my blood donation but had forgotten. Could this have caused a false reactive on the HB cAB.
Also, I had donated blood in May 2006 and not tested positive for anything on the Hepatitis testing they routinely run. I had unprotected sex about 18 weeks before this last blood donation that resulted in a positive HB cAB. My partner had unprotected sex 7 months earlier. Is it possible that I could have been exposed through him via his previous unprotected sexual encounter with the other party?
After exposure, how long does it take for the body to register a reactive result for HB cAB? And how long will the blood continue to register reactive even in the absence of a positve HB sAG test?
I've just had independent blood labs started but won't get the results for a week. I'm very confused over what the epidemiologist said, what I'm reading on line, etc., etc.
Thank you in advance for your response.
| Response from Dr. McGovern
There are several things that can cause a false positive.
The only important issue is to have a full hepatitis B panel test to determine your true test results.
False positive tests occur in about 5 percent of blood donors in general, so this occurs more often than you would expect.
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