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Serology for brucellosis
Brucellosis is an infection that occurs from coming into contact with animals carrying Brucella bacteria.
Brucella serology; Brucella antibody test or titer
How the Test is Performed
A blood sample is needed. For information on how this is done, see: Venipuncture
The blood is then tested in a laboratory to look for antibodies. For Brucella, the serum agglutination test (SAT) is the simplest and most widely used testing method.
How to Prepare for the Test
There is no special preparation.
How the Test Will Feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
Your doctor may order this test if you have signs or symptoms of brucellosis. People working in jobs where they often come in contact with animals or meat, such as slaughterhouse workers, farmers, and veterinarians, are most likely to get this disease.
A normal (negative) result usually means you have not come in contact with the bacteria that causes brucellosis. However, this test may not detect the disease at an early stage. Your doctor may have you come back for another test in 10 days to 3 weeks.
Infection with other bacteria, such as Yersinia, Francisella, and Vibrio, and certain immunizations can cause false-positive results.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
An abnormal (positive) results usually means you have come in contact with the bacteria that causes brucellosis.
However, this does not mean that you have an active infection. Your doctor will repeat the test after a few weeks to see if the test result increases. This is more likely to be a sign of a current infection.
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)
Salata RA. Brucellosis. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 318.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.