This blood test is straightforward and painless. A healthcare professional make use of a tourniquet and tie it about one inch over the elbow. They will then insert a venipuncture needle or possibly a butterfly needle. They will then connect the blood collection tube to the needle and draw the blood. Once they have enough blood they'll release the tourniquet, get rid of the needle and set a bandaid towards the needle prick. Most types of childhood arthritis are called juvenile idiopathic arthritis (JIA). JIA causes one or more joint pains and inflammation for at least six weeks.