This research will help doctors interested in the usefulness of a new test to discover hidden tuberculosis infections in patients diagnosed with rheumatoid arthritis (RA). This new test is called Quantiferon-Gold (QFT-G). After immune system medicines that block TNF-alpha (a protein manufactured by white blood cells to stimulate and activate the immune system in response to infection or cancer) started to be used, the rate of tuberculosis infections in patients treated with these medicines has increased. Doctors think that the investigators may be missing some tuberculosis infections that were hidden before the medicine is started. This new QFT-G test might better diagnose these hidden tuberculosis infections than the current tuberculosis skin test, also known as a PPD/TST. The investigators would like to compare these two tests to find out which is better at detecting these hidden infections. At the same time the investigators will measure the strength of the patient's immune system with a blood test. If you are being considered for a TNF-alpha inhibitor medicine, or are getting the patient's routine PPD/TST, the investigators are asking for the patient's participation.