15 - Hepatitis Serology

What do we use to test hepatitis serology, and how is it acquired?

Serum, acquired by letting blood clot, spinning it, then taking the top layer

Main types of detection in hepatitis serology

1. Antigen/genome: Aka a piece of the virus like a protein(Antigen) or genetic material like RNA(Genome)

2. Antibodies: IgM vs IgM + IgG

What does it mean to find a positive result in an antigen/genome test?

The virus is in the body right neow

Why do we have tests for IgM and IgM + IgG?

IgM only: Measures acute infection as it forms w/in a couple weeks and lasts a couple months

IgM + IgG: Measures if a patient has ever been exposed(Recent or any point before, since IgG lasts years)

Which hepatitis viruses cause chronic infection, and what does that make us have to do?

Hepatitis B and C, which makes us have to find out whether or not the virus is present currently by doing antigen/genome tests

HAV testing uses ___

Anti-HAV IgM

HBV testing uses ___

Antigens:

• HBsAg(Surface antigen): Positive means current HBV infection, acute or chronic

• HBeAg(E antigen): Positive indicates active replication and infectivity

IgM antibodies:

• Anti-HBc IgM antibody(Core antigen): Marks acute hepatitis B, will fade after a few months

IgM + IgG antibodies:

• Anti-HBc IgM + IgG antibodies: Marks infection at some point(but we don’t know if it’s recent or in the past) + doesn’t appear after vaccination because vaccination only has HBs antigen

• Anti-HBe(Antibody to HBeAg): A sign of replication slowing down, a good sign

HCV testing uses ___

Antigen/genome:

• HCV Ag: Core antigen, a cheaper alternative to confirm current infection

• HCV RNA: Done by PCR, confirms current infection

Antibodies:

• Anti-HCV(IgM + IgG): Just tells us if the patient has ever been exposed, not if it’s cleared out successfully or still infected

HCV core antigen and anti-HCV are often combined to make sure we don’t miss the period where there’s virus but antibodies aren’t made yet: HCV Duo

HDV testing uses ___

Anti-HDV IgM + IgG antibodies ONCE we get a patient who’s HBsAg positive

HEV testing uses ___

Anti-HEV IgM

What does ___ answer in hepatitis B?

1. HBsAg

2. IgM anti-HBc

3. Anti-HBs

4. Anti-HBe

1. HBsAg: Is the virus present now?

2. IgM anti-HBc: Is the infection recent?

3. Anti-HBs: Is the person immune/clearing the virus?

4. Anti-HBe: Has viral replication slowed?

In acute hepatitis B infection:

1. HBsAg

2. IgM anti-HBc

3. Anti-HBs

4. Anti-HBe

1. HBsAg: +

2. IgM anti-HBc: +

3. Anti-HBs: -

4. Anti-HBe: -

In convalescent hepatitis B infection

1. HBsAg

2. IgM anti-HBc

3. Anti-HBs

4. Anti-HBe

1. HBsAg: -

2. IgM anti-HBc: -

3. Anti-HBs: +

4. Anti-HBe: +

In chronic hepatitis B infection

1. HBsAg

2. IgM anti-HBc

3. Anti-HBs

4. Anti-HBe

1. HBsAg: +

2. IgM anti-HBc: -

3. Anti-HBs: -

4. Anti-HBe: +/- depending on the phase

In patient who received hepatitis B vaccine

1. HBsAg

2. IgM anti-HBc

3. Anti-HBs

4. Anti-HBe

1. HBsAg: -

2. IgM anti-HBc: -

3. Anti-HBs: +

4. Anti-HBe: -

What HBV antibody makes us think, “This patient is clear. They’ve either been vaccinated or fully recovered from an infection”?

Anti-HBs antibody