The 20-year-old student went on a mission trip to Ghana to help at a local hospital. She presented to the clinic 12 days after her return; she began to experience anorexia, flu-like symptoms, and fatigue. Ten days later, she noticed her eyes and skin looked yellow. Her history, assessment, and vitals are within normal limits except her yellow sclera and jaundiced skin. Initial lab studies reveal a total bilirubin of 16, indirect bilirubin of 8, AST of 1320 and ALT of 1400. The nurse prepares the patient for which test next?