The Centers for Disease Control and Prevention recently published updated guidelines for the use of interferon gamma release assays (IGRAs) to detect Mycobacterium tuberculosis. This document gives a balanced analysis of the strengths and weaknesses of IGRAs. To date, these assays have not been widely adopted in the United States by clinical laboratories. We have asked two experts, Thomas Alexander of Summa Health Care, who has adopted an IGRA for M. tuberculosis detection in his laboratory, and Melissa Miller of UNC Hospitals, who has evaluated one but has not chosen to adopt it, to explain how each reached this decision based on their experience with the test and the data that have been published concerning IGRA.