Reason Code 31255
Claims billed on or after July 3, 2006, TOB of 12x, 13x, 22x, 23x, 34x, 74x or 75x with revenue code 042x without an occurrence code 29, or claim billed with occurrence code 29 without revenue code 042x.
The date the outpatient physical therapy (OPT) plan was established or last reviewed (occurrence code 29) is required on all outpatient claims on which physical therapy (revenue code 42x) is billed. The reverse is also true: if occurrence code 29 is included on an outpatient claim, revenue code 42x must be billed on that claim. Please correct and resubmit.
CMS Internet Only Manual (IOM), Publication 100-4, chapter 4 (PDF).