Hepatitis B: CDC Viral Hepatitis Serology Training

Summary

This video provides an in-depth explanation of the diagnostic markers for hepatitis B virus (HBV) infection. It covers the appearance and significance of various serologic markers such as HBsAg, HBeAg, IgM anti-HBc, and anti-HBs, explaining their role in identifying acute, chronic, or past infections, as well as immunity through vaccination. The video also details how these markers are used to interpret test results, including possible outcomes for early acute infection, recovery, immunity, and chronic infection. Overall, it offers a comprehensive understanding of HBV diagnostics and serologic testing.

Takeaways

• 😀 Hepatitis B virus (HBV) can cause either acute or chronic liver disease.
• 😀 The first marker to appear after HBV exposure is the Hepatitis B surface antigen (HBsAg).
• 😀 HBsAg can be detected one month after exposure, but the time frame ranges from 1 week to 9 weeks.
• 😀 Acute symptoms of HBV typically appear 12 weeks after exposure, with a range from 9 to 21 weeks.
• 😀 The presence of Hepatitis B e-antigen (HBeAg) indicates higher viral levels and greater infectivity in acute HBV cases.
• 😀 A diagnosis of acute HBV can be made by detecting IgM anti-HBc (antibody to hepatitis B core antigen).
• 😀 Total anti-HBc (both IgM and IgG) persists indefinitely as a marker of past HBV infection.
• 😀 Anti-HBs (antibody to Hepatitis B surface antigen) indicates recovery from HBV infection and immunity from reinfection.
• 😀 The 'window period' occurs after HBsAg disappears but before anti-HBs appears, leaving only IgM anti-HBc and total anti-HBc as markers.
• 😀 Chronic HBV infection is diagnosed when HBsAg or HBV DNA is present for at least six months, or when certain markers persist.
• 😀 Successful vaccination leads to the production of anti-HBs, indicating immunity to HBV, even if the anti-HBs level declines over time.

Q & A

What is the first serologic marker to appear after exposure to HBV?

The first serologic marker to appear is hepatitis B surface antigen (HBsAg).

How long after exposure to HBV can HBsAg typically be detected?

HBsAg can typically be detected on average one month after exposure, but the detection period can range from one week to nine weeks after exposure.

What is the average time frame for symptoms of acute HBV infection to appear?

Symptoms of acute HBV infection typically appear on average 12 weeks after exposure, with a range of nine to 21 weeks.

What does the presence of HBeAg indicate in a patient with acute HBV?

The presence of HBeAg in a patient with acute HBV generally indicates higher levels of virus and greater infectivity.

What is the significance of detecting IgM anti-HBc in a serologic test?

The detection of IgM anti-HBc indicates an acute HBV infection and is typically detectable at the onset of symptoms, becoming undetectable within six to nine months.

What marker is used to indicate past HBV infection?

Total antibody to hepatitis B core antigen (total anti-HBc) is used to indicate past HBV infection and persists indefinitely.

What is the role of anti-HBs in HBV infection?

Anti-HBs is a marker that becomes detectable during convalescence and after the disappearance of HBsAg, generally indicating recovery and immunity from reinfection.

What is the 'window period' in HBV infection testing?

The window period is the time after the disappearance of HBsAg and before the appearance of anti-HBs. During this period, routine tests may only detect IgM anti-HBc and total anti-HBc.

How is chronic HBV infection diagnosed?

Chronic HBV infection is diagnosed when a patient has a positive serologic test for HBsAg, HBeAg, or HBV DNA on at least two separate samples, six months apart, or if a single positive test is accompanied by a negative IgM anti-HBc test.

What does a positive anti-HBs result indicate?

A positive anti-HBs result indicates immunity from HBV, typically after successful vaccination or recovery from past infection.