Joint Fluid
This test is done by your doctor in his office. It involves inserting a needle into a joint and removing some fluid called synovial fluid. This fluid, when examined, can tell the doctor what is causing the inflammation.
Removal of fluid can sometimes relieve the discomfort of a swollen joint. Corticosteroid may be inserted into the joint at the time of fluid removal if there is no sign of infection. This is done to reduce inflammation.