Hello doc. My mother is suffering from diabetes since 8 years. Recently her hba1c is 10.6 .her OHAs medications dose has been increased. Since 3 months she is complaining of early morning stiffness of peripheral joints of hand which resolves on activity.. Recently 1 month back she developed trigger finger... Are these symptoms of rheumatoid arthritis?? . What biochemical investigation to be done to rule out the underlying cause?