American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the marginal sensitivity of serum testing for IgG antibodies to H. pylori?

1. 75%

2. 80%

3. 85%

4. 90%

The correct answer is: 85%

The marginal sensitivity of serum testing for IgG antibodies to H. pylori is often cited around 85%. This percentage reflects the likelihood that the test will correctly identify individuals with an active infection by detecting the presence of IgG antibodies. IgG antibodies typically develop in response to an H. pylori infection, and while the sensitivity can vary based on several factors including the timing of the test and the individual patient's immune response, a value close to 85% is a common benchmark found in clinical literature. This means that while the test is generally reliable, it is not perfect, and there can be false negatives. In clinical practice, it’s important for healthcare providers to understand the limitations of antibody tests and to consider confirming positive results with additional diagnostic methods, especially in cases where clinical suspicion for H. pylori infection is high despite a negative IgG test.