CMS published a proposed rule on January 16, 2009 that would amend the Clinical Laboratory Improvement Amendments of 1988 (CLIA) regulations for cytology proficiency testing. The rule would: amend definitions, lengthen the testing interval, require validation of cytology challenges before use in testing, increase the minimum number of cytology challenges per testing event, change the grading scheme, and allow flexibility to accommodate new cytology laboratory technologies. CMS will accept comments on the proposal until March 17, 2009.