Hepatitis B Surface Antibody (HBsAb) Test?
February 6, 2018 9:36 PM   Subscribe

Tested positive for the Hepatitis B surface antibody test, what now?

Hello, thanks in advance to anyone who chimes in as I appreciate any responses. I tried out for a clinical research study for an autoimmune disease (psoriasis) which temporarily lowers your immune system. For this particular study, they did a ton of bloodwork on the potential participants/volunteers to make sure the participant is qualified and they told me that I don't qualify because I seem to have tested positive for the hepatitis b surface antibody.

Now I've done some research online and know that the antibody is the result of either a) having received the hepatitis b vaccine in the past or from being exposed to it. I don't recall getting the vaccine and I also don't engage in risky/unprotected sex, sharing needs (drug use) or homosexual relations etc although obviously there are other ways to have been infected but since it's a blood to blood infection situation Im shocked that I have tested positive for this test. Anyhow I understand the difference between having the antigen (contagious) and the antibody (immunity) and I regularly get tested often times from doing clinical studies here and there to supplement my income where they always do various hepititis/hiv test etc for eligibility but obviously they don't always do this HBsAb test as I've done research that even blood banks don't often do this test thus Im finding out now even though I'm regularly tested for general bloodwork multiple times a year.

Anyhow sorry this question was so lengthy but bottom line is there anything else I should do at this point? I'm having a hard time figuring out how commonplace it is for people to have been exposed to the hep b virus and have fought it off over time and then they test positive for the hep b surface antibody test such as myself. I realize that it is more rare for someone to get infected and remain having the hepititits b antigen which means they are contagious and thus it can lead to chronic issues etc that need to be monitored for worst case liver problems as time goes on but is there anything else I should be doing or getting done at this point? Thanks for your time.
posted by HonestAsian to Health & Fitness (7 answers total)
I am not a doctor, medical or otherwise. This is not medical advice. I don't know anything about this HEP B test specifically, so please take this with a huge grain of salt.

All (medical) tests can have false positive as well as false negative results. Normally tests for infections like HIV and other serious infections are designed in such a way that the probability of a false negative result is very low, since that would mean that someone has an infection but thinks he/she doesn't. As a result, the probability for a false positive is higher. (It can be as high as 50%, meaning half of all positive test results are false. This is a math thing.)

My understanding is that a doctor usually recommends taking a second test if an unexpected positive test result comes up. If there's a different type of test available, it might be a good idea to do a different one, but even another of the same type might help clear things up. So my advice would be to take another test if you haven't already. And please talk to your doctor and/or get a second opinion if necessary. Wishing you all the best!
posted by amf at 10:46 PM on February 6, 2018

I just realized that it is possible they did two tests before telling you it was positive, but you could at least ask about the test and the probability for false results.
posted by amf at 11:04 PM on February 6, 2018

I know you said you don't recall receiving the vaccine, but if you are in the US and less than say 35ish years old it's extremely likely you got it, unless you were specifically avoiding vaccines. Many (most?) colleges require you have it before you go, and it's part of the totally standard vaccine battery. I think the most likely explanation is that you were vaccinated, whether you remember it or not.
posted by brainmouse at 11:25 PM on February 6, 2018

Hep B Surface Antibody is a test for immunity. If it is positive (over 10.0), that means you are immune to hepatitis B. If you do other tests (Hep B surface antigen, Hep B e Antigen/Antibody, etc) it is easier to tell whether you were immunised or have "natural immunity," which could be from exposure in utero or from a past infection that you cleared on your own. Also, Hep B is much more common in some places of the world, so it can be acquired through less sinister means than drug use (like sharing a toothbrush or razor blade). In general, though, if your HBSAb is positive, that means you're immune and isn't something to worry about! And yes, depending on where you're from, you may have been vaccinated (as a kid, for travel, etc). It's now part of standard newborn immunisations in the US. (I am an NP/CNM, TINMA, IANYNP/etc).
posted by stillmoving at 11:31 PM on February 6, 2018

Missed the edit window, but wanted to add: depending on the results of the other tests (sAg, etc.) if you were at risk for HepB, we would do further testing (liver enzymes, viral load) to determine whether you have a past infection/re-infection, etc. But, it sounds like this isn't relevant for you, so you really shouldn't be concerned. Hope that helps.
posted by stillmoving at 11:57 PM on February 6, 2018

I apologize for making a presumption based on your username, but if you are Asian or Asian American, you are part of a community with disproportionately high exposure to the Hep B virus and incidence of Hep B infection. The CDC maintains a specific page on "Asian Americans and Pacific Islanders with Chronic Hep B." If you were born outside the U.S., it's quite possible you were exposed there; if you were born in the US before widespread Hep B vaccination, it's quite possible you were exposed at birth. If any of these describe you, there is no need to seek out a specific risky infection event.

I wouldn't make any presumptions based on this single intake test, but I would certainly follow up with a doctor about the result and schedule some confirmatory testing. If you don't recall any particular exposure incidents, I would worry less about being contagious and more about the possibility of chronic liver problems. Again, you should really follow up with your doctor about this, but you may be looking at medical treatments (such as antivirals) and/or reducing, or even eliminating, alcohol from your diet.

Good luck.
posted by Joey Buttafoucault at 12:37 AM on February 7, 2018

Please don't panic! Hepatitis B vaccine is given immediately after birth and then twice more during very young childhood. It is very likely you were immunized as an infant if you were born in a hospital.

HBsAb is a test for immunity, and overwhelmingly means past vaccination. HBsAg (surface antigen) is a test for active infection - this would be followed by a test (HBV DNA) for the virus itself to make sure that you were indeed actively infected. A test for past infection would be for HBcAb and HBcAg (hepatitis B core antibody and antigen). Antigen is a marker that the virus is present, antibody that there is either past vaccination or in rare cases a "cured" past infection that has actually gone on to prompt antibody production. This is really, really rare and is the holy grail of hep B treaters. (Cured is actually not a term that is used, because so far there is no proof that a former "cured" hep B infection won't reactivate in some circumstances, like immune compromise. Hence the warnings on the immune modulators used in some conditions like rheumatoid arthritis, or the antivirals is Hep C oral treatments. Successful treatment means pushing the viral level to zero and hoping the immune system perks up and produces antibodies. See why this is so complicated?)

Many, many physicians are not completely comfortable (or even competent) to order appropriate testing because it is complex. I have seen scared patients referred to a hepatologist with your test whose doctor misunderstood what the tests mean. stillmoving above mentions that your level of HBsAb should be over 10.0. He's correct, but that's for hepatitis B surface antibody TITER testing, which you probably did not have. That test is given to already vaccinated healthcare workers to see if their immunity is high enough to prevent them becoming infected if they suffer a work-related exposure, such as a needlestick. You probably had a yes-or-no test that is either positive or negative.

Your first step should be to have surface antigen testing - HBsAg. If the antigen is negative it is vanishingly unlikely that you are infected, or indeed ever were.

Anyone who is actually infected should make certain that they are cared for after diagnosis by a skilled physician, at the very least a gastroenterologist who does this often, if not a hepatologist (a liver subspecialist within the gastroenterology specialty) who is thoroughly familiar with Hep B. Diagnosis and treatment are very nuanced and improvements to treatment are frequent. I cannot emphasize the importance of skilled care because some antiviral treatments in the past caused mutation of the virus, making it more difficult to treat. Absolute adherence to the treatment schedule is also essential. Newer treatments are much better, but still not perfect.

Reputable sources for expert information include the Hepatitis B Foundation and AASLD. The Hepatitis B Foundation was formed and functions partly as an advocacy organization and partly as a research facility, and I believe they would have someone who would speak to you about your test questions. They may be able to recommend a good doctor in your area. They also have a website with lots of information. (215) 489-4900 is their phone number - they're just outside Philadelphia. Full disclosure - I know several people who work there.

AASLD is a medical organization largely of hepatology medical experts, and they also have an informative website. The acronym stands for the American Association for the Study of Liver Disease. It is geared mostly for medical professionals, but there is also basic information for consumers. I'd start with the Hep B Foundation. Their website is geared to consumers.

I did this sort of work for years, and those have been my long-time recommendations.
posted by citygirl at 12:13 PM on February 7, 2018

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