Abstract
During implementation of the Centers for Disease Control and Prevention's Mycobacterium tuberculosis nucleic acid amplification (NAA) evaluation program, 27.1% of participants used the same biological safety cabinet for NAA and specimen processing; 28.8% reported not using unidirectional workflow. An association between false positives and adverse responses to quality assurance questions (P = 0.04) illustrated the need for following NCCLS recommendations.