Anthrax serology test; Antibody test for anthrax
A normal result shows no antibodies present. During the first few days to weeks of exposure to an antigen, however, there may be slight antibody production. As the disease progresses, more antibodies will be present. If a disease is suspected, the test may need to be repeated 10 days - 2 weeks after the first test.
An abnormal result means antibodies to B. anthracis have been detected and you may have anthrax. However, some people are exposed to the bacteria and do not develop the disease. It is important to see an increase in the antibody count after a few weeks in order to diagnose a current (rather than a previous) infection.
Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases. 6th ed. London: Churchill Livingstone; 2005.
McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. St. Louis, Mo: WB Saunders; 2006; 741.