American Board of Internal Medicine (ABIM) Certification Practice Exam

What leukocyte count range is associated with noninflammatory conditions in joint fluid analysis?

1. Less than 200/µL

2. 200/µL to 2000/µL

3. 2000/µL to 5000/µL

4. More than 5000/µL

The correct answer is: 200/µL to 2000/µL

In joint fluid analysis, a leukocyte count of less than 200/µL is typically associated with noninflammatory conditions. This lower leukocyte count range suggests that there is not an ongoing inflammatory process, which is important in differentiating types of arthritis and joint diseases. Conditions such as osteoarthritis or traumatic effusions, where inflammation is not a significant factor, would result in these low leukocyte levels. For a count to be classified as noninflammatory, it is essential that the level remains below this threshold, as higher counts indicate varying degrees of inflammation, with ranges between 200/µL to 5000/µL more commonly associated with inflammatory conditions or infections. Understanding these leukocyte count thresholds helps clinicians in discerning the underlying cause of joint effusions and guiding appropriate management.