A patient on long-term peritoneal dialysis develops fever and cloudy peritoneal fluid. What should be ordered first?

When a patient on long-term peritoneal dialysis develops fever and cloudy peritoneal fluid, the most critical action is to perform a culture of the dialysis fluid. Cloudy peritoneal fluid can indicate peritonitis, a serious complication of peritoneal dialysis, often caused by an infection. Obtaining a culture of the peritoneal fluid is essential as it helps identify the causative organism.

This step is fundamental because it allows for the appropriate selection of antibiotics tailored to the specific pathogen. The culture results will inform clinical decision-making regarding the treatment plan, ensuring that the chosen antibiotics are effective against the identified organism.

While initiating antibiotics promptly is crucial in managing suspected infections, obtaining a culture first offers the best chance for targeted therapy without delaying necessary treatment. This approach minimizes the risk of antibiotic overuse and resistance while optimizing patient outcomes. Hence, collecting the culture of the dialysis fluid is the best first step in this scenario, making it the correct choice.