Sun28November0333PM 10

A patient is diagnosed with chronic hepatitis B by blood tests.

It is explained that he is extremely infectious and at increased risk of long term disease.

Which blood results are most likely?

HbSAg Anti-HBs IgM anti-HBc IgG anti-HBc HBeAg Anti-HBe

A + - + + + -

B - + - + - +

C + - - + + -

D + - - + - +

E - + - - - -

(Please select 1 option)

E

C Correct

A

B

D

Explanation

The presence of hepatitis B surface antigen infers the presence of the hepatitis B virus in host cells, that is, it is present in both chronic and acute infection.

All patients infected with hepatitis B will produce antibodies to the core antigen.

IgM antibodies are markers of acute infection and will no longer be present in chronic infection; IgG antibodies to the core antigen are present even when the infection has been cleared.

Antibody to the surface antigen arises in vaccinated individuals and once the infection has cleared thereby conferring natural immunity.

If HBsAg persists for more than six months the patient is a chronic carrier. HBeAg is essentially a marker of virus replication thus HBeAg positive carriers are extremely infectious.

Over time the HBeAg can be lost from the blood and it is possible to detect anti-HBe, these carriers are much less infectious.

Thus:

A Acute HBV infection

B Cleared HBV infection

C Chronic HBV infection - high infectivity

D Chronic HBV infection - low infectivity

E Responder to HBV vaccine

Answer Statistics

1

3%

2

50%

3

36%

4

7%

5

7%

Times answered: 301