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. Brucellosis is 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., as fewer than 200 cases are reported each year. It's more commonly found in Latin America, the Middle East, and the Mediterranean. This 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. You may get 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 brain. They can also cause infections that keep coming back. 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 healthcare provider thinks you have been exposed to brucella bacteria. They may think so if:

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

• You work in a slaughterhouse, dairy, or farm and may have been in contact with 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 come in contact while cleaning a carcass without 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 come in contact with the bacteria. Or by accident you injected yourself with the vaccine used to protect cattle against brucella. People almost never get brucellosis from contact with dogs unless their immune system is very weak from HIV/AIDS or another condition.

• You are a lab worker who may have come in contact with the bacteria.

Most people may not show symptoms of brucellosis until 3 to 4 weeks after they come in contact with the bacteria. Since the illness may not cause symptoms right away, your healthcare provider 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 healthcare provider thinks you are infected, they may order a test called an enzyme-linked immunosorbent assay, called ELISA. This test can better find out which bacteria you have. 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?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

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

Your provider will also want to do a thorough health history with you. They will ask 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 needs 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. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.