A 34-year-old woman who recently immigrated to the United States from China has laboratory tests performed prior to entering nursing school. The patient has no known past medical history and takes no medications. She is currently in a monogamous relationship and does not use illicit drugs. The patient believes she is up-to-date with all of her immunizations. She brings the following report with her to the clinic. Which of the following is the appropriate interpretation of these serological test results?

Question

A 34-year-old woman who recently immigrated to the United States from China has laboratory tests performed prior to entering nursing school.  The patient has no known past medical history and takes no medications.  She is currently in a monogamous relationship and does not use illicit drugs.  The patient believes she is up-to-date with all of her immunizations.  She brings the following report with her to the clinic.  Which of the following is the appropriate interpretation of these serological test results?

Quizplus · Accepted Answer

Explanation: This patient's serologic test results are consistent with resolved hepatitis B virus (HBV) infection. Individuals who are immune to HBV due to natural infection are positive for anti-HBs and negative for HBsAg. They are also positive for IgG anti-HBc because they form antibodies directed against the HBV core antigen. The HBV vaccine contains HBsAg, which stimulates production of anti-HBs and confers immunity in the host. However, the vaccine does not contain the core antigen so antibodies are not made against it and patients are consequently anti-HBc negative (Choice E). Serological markers for the hepatitis B virus include the following: Serological markers HBsAg: The first serologic marker detected in the serum after inoculation. It precedes the onset of clinical symptoms and elevation of serum aminotransferases. It also remains detectable during the entire symptomatic phase of acute hepatitis B and suggests infectivity. Anti-HBs: Appears in the serum after either successful HBV vaccination or clearance of HBsAg, and remains detectable for life in most patients. It indicates non-infectivity and immunity. However, there is a time lag between the disappearance of HBsAg and the appearance of anti-HBs; this is termed the "window period." HBcAg: This marker is not detectable in serum as it is normally sequestered within the HBsAg coat. Anti-HBc: IgM appears shortly after the emergence of HBsAg and may be the only diagnostic marker for acute HBV infection during the "window period." IgG remains detectable during recovery from acute HBV infection or progression to chronic infection. HBeAg: This antigen is detectable shortly after the appearance of HBsAg and indicates active viral replication/infectivity. It is associated with the presence of HBV DNA. HBeAg tends to disappear shortly after aminotransferase levels peak and before HBsAg is eliminated; it is followed by the appearance of anti-HBe. Anti-HBe: This marker suggests cessation of active viral replication and low infectivity. (Choices A and B) Acute hepatitis B infection is characterized by the presence of HBsAg and IgM anti-HBc. In contrast, chronic hepatitis B infection is defined by the presence of HBsAg in the serum for >6 months. Acute hepatitis B infection chronic hepatitis B infection (Choice C) The recovery phase of hepatitis B infection is characterized by the presence of anti-HBs, anti-HBc (predominantly IgG), and anti-HBe. Educational objective: Individuals with resolved hepatitis B infection are positive for anti-HBs and anti-HBc but negative for HBsAg. Individuals who are immunized with the hepatitis B vaccine are positive for anti-HBs but negative for HBsAg and anti-HBc. References: Hepatitis B: diagnosis and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/20387772) Hepatitis B virus infection. (http://www.ncbi.nlm.nih.gov/pubmed/24954675)

A 34-Year-Old Woman Who Recently Immigrated to the United States