Description of the blood test:

The Brucella test is a serological examination used to detect antibodies against bacteria of the genus Brucella. This infection, known as brucellosis or “undulant fever,” is a zoonotic disease, meaning it is transmitted from animals to humans—typically through the consumption of unpasteurized dairy products or direct contact with infected livestock (such as sheep, goats, or cattle). Because the bacteria can hide within the body’s cells and cause a wide range of non-specific symptoms, this laboratory test is essential for identifying the pathogen and preventing the disease from progressing into a chronic, debilitating state that affects the joints, heart, or nervous system.

What does the analysis represent?

• Specific Antibodies: Detects IgM (indicating acute/recent infection) and IgG (indicating past exposure or chronic stage) against Brucella abortus and Brucella melitensis.
• Screening and Confirmation: Often involves an initial screening (like the Rose Bengal test) followed by more precise titration (Wright’s test or ELISA) to confirm the diagnosis.
• Disease Monitoring: Helps clinicians track the effectiveness of antibiotic therapy by observing changes in antibody levels over time.
• Performance: Serological assay performed on a venous blood sample.

Recommendations for the test (General)

• Time: It is best to have the blood sample taken in the morning.
• Fasting: A food intake pause of 8 hours is recommended for the most reliable results.
• Medical History: Inform your doctor about any recent travel, consumption of raw dairy, or occupational exposure to animals (e.g., farming or veterinary work).
•  Important: If symptoms have just started, antibodies may not be high enough to detect; a repeat test in 2–4 weeks is often necessary to observe a “rising titer.”

What can affect the results?

• Cross-reactivity: Antibodies produced against other bacteria (such as Yersinia enterocolitica, Vibrio cholerae, or Francisella tularensis) can sometimes cause a false-positive Brucella result.
• Early Testing: Testing too soon after exposure (the “window period”) may yield a false-negative result.
•  Chronic State: In very long-term chronic brucellosis, IgM may be absent while only IgG remains present, requiring careful clinical correlation.

When to take the test?

• Recommendations: Prescribed for patients with a persistent, “wavy” fever (fever that rises and falls), night sweats, unexplained joint pain, extreme fatigue, or swelling of the liver and spleen.
•  Preparation: Standard preparation for venous blood collection; avoid alcohol for 24 hours prior to the test.

How to interpret the results?

The interpretation of data is the exclusive responsibility of an infectious disease specialist. A positive result indicates that the immune system has recognized the Brucella bacteria, but the specific antibody classes (IgM vs. IgG) and the titer level must be analyzed to determine if the infection is acute, chronic, or a past event. Because brucellosis can mimic many other diseases (like tuberculosis or lymphoma), only an expert can confirm the diagnosis and prescribe the specific long-term antibiotic combinations required to fully eradicate the bacteria from the body.

Possible further investigations

•  Brucella Blood Culture: To attempt to grow the bacteria from the blood (the gold standard for diagnosis).
•  Complete Blood Count (CBC): To check for low white blood cell counts or anemia, common in brucellosis.
•  Liver Function Tests: To assess if the infection has caused inflammation of the liver.
•  Consultation with an Infectious Disease Specialist: To establish a rigorous treatment plan and prevent relapses.

When does the next step make sense?

Brucellosis requires specialized medical attention because it does not resolve on its own and can lead to long-term complications. If the test is positive, the next step is an immediate consultation with a specialist to start the appropriate therapy and prevent the infection from becoming chronic.

👉 If necessary, you can discuss the test results with our specialized — infectious disease specialist (Doctors – TAMC).