Nasal Swabs in Testing for Anthrax Spores

Statement by Jan K. Carney, MD, MPH
Vermont Commissioner of Health
October 30, 2001
Contact: Nancy Erickson - 802-863-7281

There is a great deal of misunderstanding about the use of nasal swabs (and the associated nasal smear test) to detect the presence of Bacillus anthracis in the nose. Patients may be asking health care providers for a nasal swab so they can know if they "have anthrax."

The nasal swab cannot be used to diagnose anthrax infection in an individual.

The nasal smear is neither a diagnostic nor a screening test for the disease anthrax. It merely tells if spores are present, and the presence of spores does not indicate or reliably predict whether a person is at risk of becoming ill with anthrax.

The nasal swab is therefore unreliable as the basis for making decisions about precautionary medication or treatment for any individual.

The nasal swab is intended for use only in a situation where there is a potential exposure to a confirmed presence of B. anthracis in a building or location, and then only to help epidemiologists study the relationship between the presence of spores and the source of exposure.