The Centers for Medicare & Medicaid Services (CMS) and the Centers for Disease Control and Prevention (CDC) have proposed updates to the Clinical Laboratory Improvement Amendments of 1988 (CLIA) proficiency testing (PT) regulations to address the evolution in laboratory testing technology since the CLIA PT regulations were initially established in 1992. The proposed rule would, among other things, revise the list of analytes requiring PT and update the scoring criteria for acceptable laboratory performance. Comments on the proposed rule will be accepted until April 5, 2019.