American Board of Internal Medicine (ABIM) Certification Practice Exam

What synovial fluid leukocyte count is associated with inflammatory states?

1. Less than 200/µL

2. Between 200/µL and 2000/µL

3. 2000/µL

4. Greater than 2000/µL

The correct answer is: Greater than 2000/µL

A synovial fluid leukocyte count greater than 2000/µL is typically associated with inflammatory states. In the context of joint pathology, the concentration of leukocytes in the synovial fluid provides crucial diagnostic insight. Inflammatory conditions, such as rheumatoid arthritis, gout, or septic arthritis, lead to an increase in white blood cells as the immune system responds to injury or infection. Normal synovial fluid, which supports joint lubrication, typically shows a leukocyte count of fewer than 200/µL, indicating a healthy joint without inflammatory processes. When counts rise above this level, particularly when exceeding 2000/µL, it signals a significant inflammatory response occurring within the joint. This increase reflects the accumulation of immune cells, indicating a condition that warrants further investigation, potentially leading to therapeutic intervention. Consequently, recognizing a leukocyte count greater than 2000/µL as a marker of inflammatory states is essential for proper diagnosis and management of musculoskeletal disorders.