Although people think that the diagnoses of lupus, rheumatoid arthritis (RA), scleroderma, and other autoimmune conditions are plainly defined, often these diseases are not as clearly separated as one might think. Here are the three most common reasons for uncertainty in diagnosing lupus: (1) You have too many symptoms or overlap diseases. (2) You have too few symptoms. (3) You have abnormal blood test results, but no symptoms.