How long is a Letter of Medical Necessity (LMN) valid?
A Letter of Medical Necessity (LMN) is generally considered valid for up to 12 months from the date it is signed, unless your healthcare provider specifies a shorter treatment period. Once the applicable period ends, you may be asked to provide an updated LMN to confirm that the expense continues to be medically necessary.
In limited circumstances, an LMN may be approved for a longer period or for the lifetime of the member. This may apply when the medical condition is permanent or incurable and the recommended treatment or medically necessary item is not expected to change. Lifetime approvals are reviewed on a case-by-case basis. Having a permanent or incurable condition does not automatically mean an LMN will be valid for life. Because treatment recommendations can change over time, updated documentation may still be required. If your condition, recommended treatment, or medical need changes, we may request an updated LMN even if a previous LMN was approved for a longer period.