Diagnosing rheumatoid arthritis can be difficult, as sometimes blood tests come back negative when the disease is actually active in a person. X-rays can be done to see joint erosion, and a full medical history will help your rheumatologist determine the cause of your pain. Getting an early diagnosis is key, as early, aggressive treatment is important to halt the joint destruction caused by the disease. Having a good relationship with your rheumatologist is also an important factor in getting diagnosed.