To use the solution, healthcare providers turn to a local computing device—a desktop or Tablet PC running the Windows XP operating system or a Pocket PC powered by Windows Mobile software—preloaded with the NxOpinion client software (which is provided on media such as CD-ROM and flash disks). The users open a case and enter relevant patient information, such as name, age, and gender. They select relevant symptoms from the Symptoms tab and add them to the "evidence summary" by clicking a button. They add lab results, if available.

With each additional evidence item, the solution reconsiders its list of possible diagnoses, sometimes narrowing the number of possibilities, sometimes expanding them. The inference logic in the solution is sophisticated enough to tell the user when it has sufficient symptom information but may require lab results or other information. Figure 1 shows that the physician has entered four symptoms—joint pain, weight loss, anemia, and abdominal pain—and is considering a fifth, fever. NxOpinion has already developed its list of diagnoses to four. It deems rheumatoid arthritis the most likely diagnosis, with an 80 percent probability. By clicking the arrow associated with a diagnosis, the physician can view the recommended treatments.