Retro authorization for NEMT: when payers approve a trip after it happened

Prior authorization is the rule

Medicaid ride programs generally pay only for trips approved before they run, so retro authorization is an exception a program has to offer in writing. Prior authorization is the default:

• New York generally requires approval before the trip and makes no payment for a non-emergency transport without it. The claim has to match the approval to be paid.
• Texas has its Medical Transportation Program prior authorize every fee-for-service ride, and claims sent without proper authorization are denied.
• Colorado does not pay for a ride that neither its broker nor the provider authorized.
• MTM Health in Virginia tells providers to run only trips it has authorized under a unique trip ID, and it makes no promise to pay for a ride without that ID.
• Modivcare will not pay for a trip it did not assign or one missing a valid job number.

The approval usually arrives as a trip authorization number or trip ID. A trip that never had one stays unpaid unless the program offers a way to approve it afterward and the trip fits that path. On a remittance, the missing approval usually shows as reason code 197, precertification or authorization absent.

Where approval can come after the ride

Programs that allow approval after the fact limit it to a handful of situations, each with its own paperwork:

• Urgent rides with no time to write it up (California). Under 22 CCR 51323(b)(2)(A), when care is urgent and a written request could not reasonably have gone in first, the transportation provider may ask for authorization by phone. The phone approval counts only once a written request confirms it. For Medi-Cal plan members, the plan may approve by phone under All Plan Letter 22-008 when a Physician Certification Statement (PCS) could not reasonably be sent beforehand, and the member’s provider has to submit the PCS after the service for the phone approval to stand.
• Urgent county-approved rides (Wisconsin). Wisconsin’s administrative code requires common carrier rides to be approved before departure, but it makes urgent ones subject to retroactive approval by the county, the tribal agency, or its designee (DHS 107.23(3)(c)1). The same agencies may also authorize a ride afterward when an emergency outside the rider’s control, such as a weekend trip to the emergency room, blocked approval in advance (DHS 107.23(1)(d)5). They may ask the medical or transportation provider for proof the ride was needed.
• Riders found eligible after the ride. CMS guidance of September 28, 2023 (SMD 23-006) requires states to pay claims for covered services given during a beneficiary’s retroactive eligibility period, transportation included, even if someone already paid for the service. A provider might need to refund the rider or family before billing the state. New York takes a trip attestation for such a rider for 120 days, counted from the day the coverage shows up in the state’s verification system. Its broker, Medical Answering Services, takes these requests on a Backdated Trip Request Form sent to backdatedtrips@medanswering.com, with a box for a rider whose Medicaid is pending. ForwardHealth’s NEMT handbook in Wisconsin says a service that normally needs prior authorization still needs a request and approval before the claim, even in the retroactive period.
• Emergencies on the ambulance side (Idaho). When an emergency rules out prior authorization for an ambulance transport, Idaho Medicaid takes a post authorization request by fax with the claim form, the patient care report, and any explanation of benefits, and answers in writing. Idaho’s non-ambulance rides are arranged by MTM, and this process is for ambulance claims.
• Fixing an approval already issued (New York). A correction to an existing prior authorization can be approved when it is asked for inside 90 days of the ride. Past 90 days, it can still be approved if no more than 30 days have gone by since the approval was issued, and anything later may be denied. Requests sent over 90 days after the ride go to the state Department of Health, by eFax at (518) 486-2495 or email to MedTrans@health.ny.gov.

For the 2027 change that shortens how far back retroactive coverage reaches, see retroactive Medicaid eligibility. Under Public Law 119-21 (section 71112), for applications filed from January 1, 2027, coverage reaches back a single month for expansion adults, while other applicants get two.

Rides that skip the usual approval step

Some trips never need retro approval because the usual advance approval does not apply to them. Chasing one wastes time:

• Medi-Cal hospital transfers. Fee-for-service Medi-Cal needs neither a TAR nor a prescription nor a clinician’s signature to move an acute hospital inpatient into a Level A or B nursing facility. All Plan Letter 22-008 waives prior authorization for plan members in the same situation and for emergency room patients being admitted.
• Colorado urgent trips. Since January 1, 2019, medical facilities can book urgent rides directly with eligible transportation providers instead of going through the state’s broker. Urgent covers rides after a hospital discharge, rides when the scheduled NEMT provider fails to collect a member from an appointment within an hour of the pickup time, and rides to critical, unplanned appointments.
• New York ambulance. Emergency ambulance trips need no prior authorization, and neither do Medicare-approved ambulance trips for dual eligibles with Part B.

More on discharge rides is in hospital discharge transportation.

Request windows

The clock starts on a different date in each program, and a missed window usually ends the claim. These are the windows the state manuals and New York’s broker set:

Brokers set their own windows by contract and handbook. Modivcare’s Mississippi manual, for example, cuts an invoice by 10 percent after 60 days and disallows it after 120. Your state’s first filing limit is under timely filing limit.

What to record when a ride runs ahead of its approval

A retro request succeeds on the notes made that day. Write down:

1. Who asked for the ride. The facility, the staff member’s name and number, and the time of the call.
2. Why it could not wait. A discharge, urgent care, or the scheduled provider failing to arrive.
3. Your call to the broker or plan. The time, the person, and any reference number. In California, the phone approval still needs written confirmation.
4. The clinician’s paperwork. Who will send the PCS or medical necessity form, and by when.
5. The ride itself. Times and addresses at both ends, the driver and vehicle, and the rider’s signature, kept the way NEMT documentation requirements describes.
6. The rider’s coverage. For a rider with an application pending, the date you checked and what the state system showed. New York expects providers to keep checking until the retroactive approval and its start date appear. The checks themselves are covered in NEMT eligibility verification.

Keep the notes with the trip. If the request goes to appeal, they are the evidence.

When the approval never comes

A trip log proves a ride happened. It does not prove anyone approved it. New York denies the authorization request outright when the rider never becomes eligible for the date of service, and it denies retroactive requests that arrive after the 120-day window. Brokers that pay only assigned trips will not pay a ride they never assigned, however well it was documented.

Billing the rider instead is limited. Texas lets a provider decline Medicaid for a client’s retroactive period and bill the client directly, as long as the provider applies that policy to every client in the same position and tells the client before services. A Texas provider that does accept Medicaid for the period has to refund the client’s payments before billing Medicaid. Rules elsewhere differ, as charging Medicaid patients for transportation explains.

If the program denied a retro request that met its rules, the next step is an appeal.

Keeping the record ready for a late approval

HealthRide’s trip log lists every leg with the addresses at both ends, scheduled versus actual times, the driver and vehicle, and GPS-verified miles, and each trip keeps the signatures captured on screen. The log exports as a spreadsheet or a print-ready PDF. Every change is recorded, so a late approval can be matched to the trip as it actually ran.