A blood sample is needed.

The sample is sent to a lab where it is examined for Francisella antibodies using a method called serology. This method checks if your body has produced substances called antibodies to a specific foreign substance (antigen), in this case, F. tularensis.

Antibodies are proteins that defend your body against bacteria, viruses, and fungi. If antibodies are present, they are in the serum of your blood. Serum is the liquid portion of blood.

There is no special preparation.

When the needle is inserted to draw blood, you may feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or bruising. This soon goes away.

This blood test is done when tularemia is suspected.

A normal result is no antibodies specific for F. tularensis are found in the serum.

Normal value ranges may vary slightly among different labs. Some labs use different measurements or may test different specimens. Talk to your health care provider about the meaning of your specific test results.

If antibodies are detected, there has been exposure to F. tularensis.

If antibodies are found, it means you either have a current or past infection with F. tularensis. In some cases, a single high level of antibodies that are specific to F. tularensis means you have a current infection.

During the early stage of an illness, few antibodies may be detected. Antibody production increases during the course of an infection. For this reason, this test may be repeated several weeks after the first test.

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Taking blood 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 lightheaded
• Multiple punctures to locate veins
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Tularemia test; Serology for Francisella tularensis

Aoyagi K, Ashihara Y, Kasahara Y. Immunoassays and immunochemistry. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 45.

Bloch KC, Lopez FA. Tularemia and other Francisella infections. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 287.

Dietrich EA, Auwaeter PG, Nelson CA. Francisella tularensis (tularemia). In: Blaser MJ, Cohen JI, Holland SM, et al, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 10th ed. Philadelphia, PA: Elsevier; 2026:chap 232.

Updated by: Jatin M. Vyas, MD, PhD, Roy and Diana Vagelos Professor in Medicine, Columbia University Vagelos College of Physicians and Surgeons, Division of Infectious Diseases, Department of Medicine, New York, NY. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.