Ignore medically unlikely edits at your peril for claim rejection. Medicare denials could mean you're running up against medically unlikely edits (MUEs). Designed to prevent overpayments caused by gross billing errors (usually a result of clerical or billing systems' mistakes), MUEs often confuse even veteran coders. Ensure you're not letting MUEs wreak havoc on your practice's coding and reimbursement by uncovering the truth about four aspects of these edits. Myth 1: MUE Edits Don't Affect Your Practice Some practices feel that they don't need to worry about MUEs. Reality: "They limit the frequency a CPT code can be used," says Chandra L. Hines, business office manager at a practice in Raleigh, N.C. "We need to become aware of the denials and not let every denial go because the insurance company said it was an MUE." The MUE list includes specific CPT or HCPCS codes, followed by the number of units that CMS will pay. CMS developed the MUEs to reduce paid claims error rates in the Medicare Program, says Jillian Harrington, MHA, CPC, CPC-P, CPCI, CCS-P, president of ComplyCode in Binghamton, New York. For instance Note: Myth 2: You Can Bill the Patient to Overcome MUE Limits Some practices believe that by having the patient sign an advance beneficiary notice (ABN) you can pass on the cost of procedures you know will be denied due to MUEs. Reality: CMS makes this rule very clear in its FAQs, stating: "A provider/supplier may not issue an ABN for units of service in excess of an MUE." Myth 3: You Can Never Override an MUE Don't think that even if your physician performs a legitimate, medically necessary procedure that violates MUE edits, you can't override the edits. Reality: Check your payer's reporting preference: CMS notes that modifiers 76 (Repeat procedure by same physician) and 77 (Repeat procedure by another physician) are among your options to override an MUE, as are the anatomical modifiers, such as RT (Right side).You may also use modifier 59 (Distinct procedural service), but Harrington cautions you to use this only if no other modifier is appropriate. Expect to supply documentation showing medical necessity for the additional units. Myth 4: You Can't Appeal an MUE Denial If your practice receives a denial based on an MUE, you may think that you cannot appeal that denial. Reality: Tip: