American College of Physicians (ACP) , the second largest physicians group in the United States, makes the following recommendation in its Best Practices Advice: "Doctors should use a patient's history and physical examination to determine whether the low back pain is musculoskeletal or due to a serious condition. Doctors should not order x-ray, CT, or MRI unless they suspect a serious cause of low back pain. Patients with musculoskeletal low back pain need information so tha