Diagnostic Criteria for Chronic HBV Infection

Chronic HBV infection is a necroinflammatory disease of the liver caused by persistent infection with HBV, and can be categorized as hepatitis B e antigen (HBeAg) positive or negative. Inactive hepatitis B surface antigen (HBsAg) carriers have HBV infection of the liver without significant, ongoing necroinflammatory disease. HBV infection is resolved when there is no further virologic, biochemical, or histologic evidence of active viral infection or disease.

Diagnostic criteria related to HBV include the following:

• Chronic hepatitis B: HBsAg positive for more than six months, serum HBV DNA greater than 20,000 IU per mL (lower values of 2,000 to 20,000 IU per mL often occur with HBeAg-negative chronic hepatitis B), persistent or intermittent elevation in alanine transaminase (ALT) or aspartate transaminase (AST) levels, and liver biopsy showing chronic hepatitis with moderate or severe necroinflammation.
• Inactive HBsAg carrier state: HBsAg positive for more than six months, HBeAg negative and anti-HBeAg positive, serum HBV DNA less than 2,000 IU per mL, persistently normal ALT and AST levels, liver biopsy confirming absence of significant hepatitis.
• Resolved hepatitis B: known history of acute or chronic hepatitis B or the presence of anti-hepatitis B core antigen (anti-HBcAg) with or without anti-HBsAg, HBsAg negative, undetectable serum HBV DNA (very low levels may be detectable with sensitive prostate-specific antigen assays), and normal ALT levels.

References:

1. Kuo A, Gish R. Chronic hepatitis B infection. Clin Liver Dis. 2012 May;16(2):347-69.[Medline]
2. Liaw YF, Chu CM. Hepatitis B virus infection. Lancet. 2009;373:582–92. [Medline]
3. Bonino F, Piratvisuth T, Brunetto MR, Liaw YF. Diagnostic markers of chronic hepatitis B infection and disease. Antivir Ther. 2010;15 Suppl 3:35-44. [Medline]

Typical Serologic Course of Hepatitis A Virus (HAV) Infection

Since both clinically and biochemically, acute hepatitis due to HAV cannot be distinguished from that due to the other hepatitis viruses, serologic tests are necessary for a virus-specific diagnosis.

Diagnosis of hepatitis is made by biochemical assessment of liver function (laboratory evaluation of: urine bilirubin and urobilinogen, total and direct serum bilirubin, ALT (SGPT) and/or AST (SGOT), alkaline phosphatase, prothrombin time, total protein, albumin, IgG, IgA, IgM, complete blood count).
The specific routine diagnosis of acute hepatitis A is made by finding anti-HAV IgM in the serum of patients. A second option is the detection of virus and/or antigen in the faeces.
Virus and antibody can be detected by commercially available radioimmunoassay (RIA), enzyme immunoassay (EIA) and enzyme-linked immunosorbent assay (ELISA) kits. These commercially available assays for anti-HAV IgM and total anti-HAV (IgM and IgG) for assessment of immunity to HAV are not influenced by the passive administration of immunoglobulin (IG), because the prophylactic doses are below detection level.
At the onset of disease, the presence of IgG anti-HAV is always accompanied by the presence of IgM anti-HAV. As IgG anti-HAV persists lifelong after acute infection, detection of IgG anti-HAV alone indicates past infection.
Virus may still be present in the absence of detectable HAV antigen, as demonstrated by the use of more sensitive methods.




References:

1. Nainan OV, Xia G, Vaughan G, Margolis HS. Diagnosis of hepatitis a virus infection: a molecular approach. Clin Microbiol Rev. 2006 Jan;19(1):63-79. [Medline]
2. Regev A, Schiff ER. Viral hepatitis A, B, and C. Clin Liver Dis. 2000 Feb;4(1):47-71. [Medline]
3. Advisory Committee on Immunization Practices (ACIP), Fiore AE, Wasley A, Bell BP. Prevention of hepatitis A through active or passive immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2006 May 19;55(RR-7):1-23. [Medline]