How is Hepatitis A Infection Diagnosed?
At onset, the various human hepatitis viruses cause very similar illnesses. Therefore, neither the individual nor the healthcare provider can tell by symptoms or signs if a given individual is suffering from hepatitis A. Fortunately, blood tests are widely available to accurately diagnose hepatitis A. These are tests for antibodies, or the affected person’s immune response to hepatitis A proteins. Immunoglobulin M (IgM) antibodies, which indicate acute disease, and immunoglobulin G (IgG) antibodies, which stay positive for life, should both be measured. Following is the interpretation of the results: • IgM negative / IgG negative: Most persons with these results have never contracted hepatitis A. Antibodies of the IgM variety develop five to ten days prior to the onset of symptoms. • IgM positive / IgG negative: This result indicates acute hepatitis A. • IgM positive / IgG positive: This result indicates that acute hepatitis A occurred within the last six months. By six months, the IgM
