Medical Fun Facts Podcast

MFF0058: Basic Hepatitis B virus serology

It’s Thursday 20 April 2017 and it is payday.

Tonight, I want to touch on a little bit of serology, specifically, the basic serology associated with infection from Hepatitis B virus. This is my ideal world view of HBV serology and shouldn’t be interpreted in conjunction with health insurance payment schedules or payments in general. This view is patient-centred and what I’d like to do if cost wasn’t an issue.

I think everyone should know their HBV status. We live in a world were HBV infection can be prevented in most people through immunisation. In fact, the HBV immunisation was the first vaccine to prevent a malignant disease, i.e., hepatic carcinoma or liver cancer (yeah, I know I don’t like saying cancer but for ease of use in the podcast I said it).

In some patient populations, HBV is often transmitted vertically through childbirth so childhood immunisation is important. HBV can also be transmitted sexually and via blood. That means via blood, organ and tissue transplantation when the source hasn’t been screened for HBV and in intravenous drug users. Fortunately, in countries like Australia, the chance of being infected with HBV as a result of receiving a blood transfusion or a transplant of an organ or tissue is exceedingly low. This is because of stringent use of testing protocols to screen the source of infections that may be transmitted. Australia can boast of the safest blood transfusion system as well as an amazingly safe organ and tissue transplantation service.

HBV transmission between IV drug users is a good reason for needle exchange programs to ensure people use clean needles and clean syringes.

In my ideal world, the first time someone is tested for HBV status, three tests would be performed, i.e., HBs, αHBs, and αHBc. The results from these three serological assays can give a referring medical practitioner information on how to proceed. For example, it may be to immunise and ensure HBV immunity after the series of immunisations. The results may suggest the patient has an active infection, so the patient requires further testing to determine how infectious the patient may be and referral for follow up treatment. The patient may demonstrate evidence of past infection and so no further action is necessary, not even further booster immunisation. If a patient has been immunised, most people react and produce αHBs and boosters are not necessary. When all three assays are reactive, it may represent current seroconversion so the patient requires further testing and follow up.

I’d normally draw up a table but most blog platforms don’t handle tables very well. I’ve added some extra text in the show notes to demonstrate what I mean by all these results.

HBs NR, αHBs NR, αHBc NR→Not immune, Immunise

HBs R, αHBs NR, αHBc R→Infectious, proceed to HBV DNA, HBe, and αHBe

HBs NR, αHBs R, αHBc R→Immune, booster immunisation as per Australian Immunisation Handbook is not required

HBs NR, αHBs R, αHBc R→Past infection, no further action necessary

HBs NR, αHBs NR, αHBc R→Past infection, no further action necessary

HBs R, αHBs R, αHBc R→Probable seroconversion, proceed to HBV DNA, HBe, and αHBe

If you don’t know your HBV status, I’d suggest speaking with your doctor. How your doctor proceeds depends on your sexual history and any other risk factors you may have.

Whenever you’re ever exposed to blood, it’s important to be checked, not only for HBV but also other blood-borne pathogens. The same is true if you’re exposed sexually to unknown risks depending on the sexual encounter.

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