Hepatitis Antibodies and Immunisation

Hepatitis A

Two tests:

  • Hepatitis A total antibody (measures IgA and IgM)
  • Hepatitis A specific IgG

If their either total antibody is up after immunisation or specific IgG is up then immunity is assumed.

Diagnosis of Hep A is difficult and can be done with Hep A IgM (but gives false positives) or Hep A PCR

Hepatitis B

Hep B surface antigen (HBsAg)

  • if positive patient has current Hep B infection
  • positive for over 6 months in chronicly infected patients
  • false positive occurs if checked following recent vaccination

Hep B surface antibody (HBsAb or Anti-HBs)

  • high if patient has immunity
  • (but does decrease eventually – but that doesnt mean they’ve lost immunity)

Hep B Surface antibody is the only thing you can have positive and not have  (or have had) infection  (s…antibody = santa’s body wouldn’t ever have had Hep B) 

Hep B core antibody (HepBcAb or Anti-HBc)

  • This is not in the vaccination so if patient has these they have been exposed to the actual virus at some point
  • It’s presence does not confer immunity – it’s present in actively infected people

Hep B e antigen (HepBeAg or HBeAg)

  • Patients with this have infection and are infectious

(Hep B E antigen = they BE very infectious!)

Hep B e antibody (HeBeAb or Anti-HBe)

  • When present sometimes indicates the virus is coming under control – not always though

Hep B PCR

  • sensitive method for finding the Hep B virus

 

Hepatitis C

  • if they have abnormal LFTs and
  • antibodies to Hep C (anti-HCV)
  • then they probably have infection
  • But some patients clear the virus and the antibodies remain – though they wane over time