What the risks are:

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Special considerations:

A serology test can determine if a patient has ever been exposed to a particular antigen, but this does not necessarily indicate a current infection. A person who tests positive for B. anthracis may not develop anthrax.

The best test for diagnosing anthrax is a culture of affected tissue or blood.