A nurse is reinforcing teaching about laboratory testing with an adolescent who has suspected juvenile idiopathic arthritis. Which of the following laboratory tests should the nurse include?

A. Alanine aminotransferase (ALT) is a liver enzyme and not typically relevant for diagnosing juvenile idiopathic arthritis. B. Erythrocyte sedimentation rate (ESR) is a marker of inflammation and is commonly used in the evaluation and monitoring of juvenile idiopathic arthritis. C. Potassium levels are not directly related to juvenile idiopathic arthritis and its diagnosis. D. BUN (blood urea nitrogen) is a measure of kidney function and is not specific to juvenile idiopathic arthritis.