MRCP2-2201

A 68-year-old man arrives at the emergency department after falling and injuring his back. He had been experiencing lower back pain prior to the fall, which only worsened slightly after the incident. A CT scan reveals lytic lesions in his lumbar vertebrae, leading to suspicion of multiple myeloma. Blood and urine tests further support this diagnosis, and he is scheduled for a bone marrow biopsy. What test can provide prognostic information before the biopsy for this patient?