EMS Signatures | Part 2: CMN Signatures

Welcome to part two in our series on EMS signature issues! In our previous post we talked about the rules for beneficiary signatures and the Authorization of Benefits (AOB). In this post we’ll discuss the PCS form, or the Certificate of Medical Necessity (CMN) as it is now known.


A Quick Note About the CMN

Most of our readers should already be familiar with the PCS form. However, in case you missed it, in 2020 CMS made changes to the requirements for the form and thus created two categories: the Physician’s Certification Statement and the Non-Physician Certification Statement. Collectively, these two forms are referred to as a CMN to account for the different types of signers.


What Does the CMN Do?

The CMN is a required form for most non-emergency transports covered by Medicare and many other insurers. The form is a statement that the patient requires transport by ambulance and is signed by a qualified provider (discussed below). The CMN is used for both unscheduled non-emergency transports and scheduled repetitive non-emergency transports.


Who Can Sign What?

As stated above, the two types of CMN reflects the two different types of signers (physicians and non-physicians) certifying that the patient requires an ambulance for transport. The distinction between what a physician can sign for and what the other qualified signers can sign for is important and can affect whether a transport meets coverage criteria. As a reminder, when a CMN is required, it is a key part of medical necessity documentation and if it is incomplete or incorrect, then medical necessity will not be met.


Physician CMN

The physician signed CMN can be used for any type of non-emergency transport, scheduled or unscheduled, and is the preferred option in all cases. To qualify, the signer must be the patient’s attending physician. The most important thing to note is that the physician is the only provider who can sign for repetitive transports. As a reminder, repetitive transports start when there are 3 transports for the same service (i.e., dialysis, wound care, etc.) in a 10-day period or at least one transport each week for three consecutive weeks for the same service. Once a transport is considered repetitive, only a physician can sign the CMN.


Non-Physician CMN

Non-Physician signed CMNs can only be used for non-repetitive transports and must meet more criteria. The criteria for non-physician signatures are as follows:

  • Has personal knowledge of the beneficiary’s condition at the time the ambulance transport is ordered or the service is furnished;
  • Who must be employed:
    1. By the beneficiary’s attending physician; or
    2. By the hospital or facility where the beneficiary is being treated and from which the beneficiary is transported;
  • Is among the following individuals, with respect to whom all Medicare regulations and all applicable State licensure laws apply:
    1. Physician assistant (PA)
    2. Nurse practitioner (NP)
    3. Clinical nurse specialist (CNS)
    4. Licensed practical nurse (LPN)
    5. Social worker
    6. Case Manager
    7. Discharge planner


What About the Rest of the Form?

If you’re familiar with the sample CMN form provided by PWW or something similar, then you’re aware that there are other fields included in the form identifying the patient, the transport information, and medical necessity. We’d like to briefly mention these fields because many of our clients express confusion about the medical necessity section when it doesn’t match what their crews find when they assess the patient.

As common sense would tell you, the sections containing demographic information should reflect the actual transport. When reviewing the CMN, staff should always confirm that these are correct and they should require corrections to this information if it is inconsistent with the transport that was requested. However, the medical necessity section is completed based on the provider’s knowledge and assessment of the patient, which is treated different from demographic information. It is not up to EMS staff to tell the provider what to put in this section. In some cases the patient’s condition may be different during the transport than what was written in the CMN. Contradicting information does not invalidate the transport or the CMN. For the medical necessity section, we recommend that EMS staff review it to confirm it is completed.


Key Signature Issues

Now that we understand which signers can sign which types of CMNs, lets note some quick recommendations for your staff to check when reviewing CMNs:

  • The provider’s signature must be handwritten in ink or a digital/electronic signature. However, for electronic signatures, there must be a method to verify the signature.
  • A signature that is legible is acceptable without a printed name.
  • Illegible signatures can be supported by a printed name under the signature.
  • Stamped signatures are not permitted.
  • When a CMN must be signed by a physician, a signature “for the physician” by another provider is unacceptable.
  • The signer should either write their credential by their signature or circle it from a list of options on the CMN form.
  • If a signature is illegible and there isn’t a printed name under it, staff may obtain a signature log from the provider facility to support their signature and credential, or obtain an attestation signed by the signer stating that the signature on the CMN is their own.
  • The signature should also include a clear date. Undated CMNs can also cause the CMN to be invalid.



It’s important to keep your staff disciplined in their review of CMNs. CMNs that fall through the cracks, especially repetitive CMNs, can cause large overpayments due to a single mistake. We encourage all clients to use the CMN template and instructions provide in the link above, and also encourage training staff to identify other acceptable forms of the CMN when a standard form is not used.

We hope this post on CMN signatures was helpful and we hope that you contact us with any questions about this topic!