A nurse is reviewing the laboratory results of a child who was recently admitted for suspected rheumatic fever. The nurse should identify that which of the following laboratory tests can contribute to confirming this diagnosis? Select all that apply.

A. C-reactive protein (CRP) is an inflammatory marker that increases in response to inflammation, including in conditions like rheumatic fever. B. An elevated antistreptolysin O (ASO) titer indicates a recent streptococcal infection, which is a key contributor to the development of rheumatic fever. C. Partial thromboplastin time (PTT) measures blood clotting, which is not directly related to diagnosing rheumatic fever. D. Blood urea nitrogen (BUN) assesses kidney function and is not specific to diagnosing rheumatic fever. E. Erythrocyte sedimentation rate (ESR) is another inflammatory marker that increases with infection and inflammation, helping to support the diagnosis of rheumatic fever.