Certificate of Medical Necessity
A formal document, typically completed by a prescribing physician, attesting that an orthotic device or other durable medical equipment is medically necessary for a specific patient's condition.
Full Definition
A Certificate of Medical Necessity (CMN) is a standardised or insurer-specified form that a physician must complete and sign to justify the prescription of durable medical equipment (DME), including orthoses, to a third-party payer such as Medicare or a private insurer. In orthotics billing, the CMN provides clinical justification that links the prescribed device to a documented diagnosis and functional limitation. Editors working on orthotics administrative documents should not confuse a CMN with a Letter of Medical Necessity (LMN), which is a narrative letter rather than a structured form. CMN content requirements are defined by payer and device type, and editors should preserve all required fields without paraphrasing clinical language in ways that could invalidate the document. In the United States, specific CMN forms are mandated for Medicare DME billing.
Usage
Usage note: Always use the full title on first use before introducing the acronym CMN. Do not conflate with Letter of Medical Necessity.
In Context
- "The claim was rejected because the Certificate of Medical Necessity had not been signed by the prescribing physician before submission." — Insurance billing correspondence
- "A Certificate of Medical Necessity is a structured form, whereas a Letter of Medical Necessity is a narrative document; editors must not use the two terms interchangeably." — Compliance training manual