Which laboratory tests are recommended in cases of suspected reactive arthritis?

In cases of suspected reactive arthritis, it is essential to evaluate the inflammatory status and potential underlying infectious causes. This involves the use of inflammatory markers and serologic tests, which can provide valuable insights into the patient's condition.

Inflammatory markers such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) help determine the level of inflammation present in the body. Elevated levels of these markers can support the diagnosis of arthritis. Additionally, serologic tests can help identify previous infections, particularly those associated with reactive arthritis, such as certain sexually transmitted infections or gastrointestinal infections. These tests may include screening for Chlamydia trachomatis, as infections with this organism are commonly associated with reactive arthritis.

The other options, while offering some form of testing, do not address the specific diagnostic needs for reactive arthritis. A pregnancy test, for instance, can be important for other clinical scenarios but would not provide relevant information regarding reactive arthritis. A basic metabolic panel focuses on electrolytes and organ function rather than inflammatory processes. Similarly, a complete blood count alone would provide limited insight without the context of inflammation or specific serology tests to assess for infections. Thus, the comprehensive approach of including inflammatory markers and serologic tests is necessary