Brucella Antibody

Does this test have other names?

Brucella agglutination titer, Brucella antibody titer, Brucella-specific agglutination, Brucella microagglutination test, BMAT, standard tube agglutination test

What is this test?

This is a blood test for brucellosis, an infectious disease usually caused by handling animals or milk products infected with the brucella bacteria. If you have brucellosis, your body will make certain antibodies to fight the brucella bacteria. This test looks for those antibodies in your blood.

The brucella bacteria can infect dogs and livestock, including cows, sheep, camels, goats, and pigs. Recently, brucella bacteria have also been found in ocean mammals, including seals.

The disease is rare in the U.S., where fewer than 200 cases are reported each year. It's more commonly found in Latin America, the Middle East, and the Mediterranean, which is why it's often called Mediterranean or Malta fever. It's also called undulant fever, Bang's disease, and Gibraltar fever.

If you are exposed to brucella bacteria, you may develop brucellosis. Your symptoms may not show up right away. But if the disease isn't treated after a few months, you may start to feel unusually weak or develop a fever and chills, headaches, backache, muscle and joint pain, and sweats. You may lose your appetite and appear anorexic. If untreated, the bacteria can sometimes damage the heart, joints, or central nervous system or cause recurring infections. If you are pregnant and have brucellosis, it may cause a miscarriage or infect your unborn child. 

Why do I need this test?

You may have this test if your doctor suspects you have been exposed to brucella bacteria, particularly if:

• You work in a slaughterhouse and have symptoms of the illness.

• You work in a slaughterhouse, dairy, or farm and may have been exposed to the bacteria through a cut or open wound.

• You hunt deer, wild pigs, or other animals and have symptoms of the illness.

• You may have been exposed while cleaning a carcass if you didn't wear gloves.

• You have traveled to Spain, Greece, Mexico, or another country where brucellosis is common and have eaten unpasteurized milk, cheese, or ice cream.

• You are a veterinarian and may have been exposed to the bacteria or accidentally injected yourself with the vaccine used to protect cattle against brucella. People almost never develop brucellosis from contact with dogs unless their immune system is extremely weak from HIV/AIDS or another condition.

• You are a lab worker who may have been exposed to brucella bacteria.

Most people may not show symptoms of brucellosis until three to four weeks after they are exposed to the bacteria. Since the illness may not cause symptoms right away, your doctor may not know the cause of your symptoms until you have this test. 

What other tests might I have along with this test?

In some cases, you may get a false-positive with this test. If your doctor suspects you are infected, he or she may order a test called an enzyme-linked immunosorbent assay, called ELISA, which more accurately identifies the bacteria. You may also need to have blood, bone marrow, or other tissue tested in order to confirm that you have brucellosis.

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.

A normal result will be negative for the antibodies. But your doctor may want to repeat the test or do other tests to confirm the results. False-positives are also common, so you may need other confirmatory tests after a positive result, too.

Your doctor will also want to do a thorough history with you, asking about your work, your travel to areas where brucella bacteria are common, and any foods or beverages you've eaten that may have been contaminated. 

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.

What might affect my test results?

False-positives are common in part because your body can make the same antibodies as a reaction to other germs.

How do I get ready for this test?

You don't need to prepare for this test.