CMS Brain CT metric found to be unreliable

A new CMS metric, the OP-15, developed to evaluate the appropriate use of brain CT in the emergency department for atraumatic headache, is not reliable, according to a study in the Annals of Emergency Medicine.

For the study, researchers examined patient records for 748 patients that were found to have inappropriate head CTs in the ER, per the OP-15 metric.  Key findings:


  • The researchers found that 65% of these scans were actually appropriate.
  • Another 18% of the CT scans were performed for legitimate reasons that were documented in the patients' charts.
  • In total, the measure was accurate only 16.7% of the time.


The authors conclude that the measure is not reliable or valid.

(Sources: The Advisory Board Daily Briefing,, February 24, 2012; The Annals of Emergency Medicine,, February 2012)