Maryland Medicaid Behavioral Health Billing: Carelon, ePREP and MCO Basics

Maryland Medicaid behavioral health billing runs on two tracks. Managed care organizations (MCOs) pay for primary behavioral health care. A state contractor, Carelon Behavioral Health, runs the specialty system. The track decides who you enroll with, where the claim goes, and who you call when it denies. This guide to Maryland Medicaid behavioral health billing covers both tracks for psychotherapists and psychiatrists. Sources were checked on October 9, 2026.

The two Maryland Medicaid tracks

Maryland splits behavioral health coverage into managed care and a “carved-out” specialty system. A carve-out is a service the state pays directly instead of through MCOs. Maryland’s Medicaid behavioral health coverage page describes the split.

Track	What it covers	Who pays you	What you must do
Primary behavioral health	Mild conditions, such as mild depression or anxiety	The member’s HealthChoice MCO	Enroll with Medicaid through ePREP (the state’s online enrollment portal) and join the member’s MCO
Specialty behavioral health	Serious mental illness and substance use disorder	Maryland Medicaid fee-for-service, run through Carelon	Enroll through ePREP and register with Carelon

Prescribers, note one more split. The same state page says most behavioral health medications are also carved out of managed care. The Maryland Medicaid fee-for-service pharmacy program processes those claims. Your visit and the prescription can follow different payers. Our eligibility terms glossary explains carve-outs in plain English.

How do I bill Maryland Medicaid for therapy?

Enroll in Maryland Medicaid through ePREP. Check whether the member’s service is primary or specialty. Send primary claims to the member’s MCO after you join its network. Send specialty claims to Carelon after you register with Carelon. Verify eligibility and plan on the date of service, every time. Our insurance verification service page shows what a clean check looks like.

Step 1: Enroll through ePREP

ePREP is the Electronic Provider Revalidation and Enrollment Portal. It is Maryland Medicaid’s online system for enrolling, revalidating and updating provider records. The state’s ePREP guide for behavioral health providers says:

• Every portal user needs a user profile. The business profile holds your NPIs, Medicaid numbers and tax IDs.
• Provider accounts are built on NPI, provider type and location. Change any one and you get a new account.
• Rendering providers should not share a business profile with their group. Each one needs a separate email, user profile and business profile.
• Medicaid enrollment must be renewed at least every five years. ePREP tells you when to apply.

That guide is dated April 2020. Check the live ePREP screens before you rely on the steps. For the bigger picture of getting on payer networks, read our credentialing and network status guide.

Step 2: Register with Carelon for specialty claims

Carelon is Maryland’s behavioral health administrative services organization (ASO). An ASO handles authorizations, claims processing and provider management for the state. Carelon replaced Optum. The Maryland Department of Health’s ASO transition report gives the dates. Providers began sending claims to Carelon on December 22, 2024. Carelon began processing claims on January 1, 2025. Its first check run was January 6, 2025.

Registration runs through the Carelon Provider Digital Front Door, linked above. It is built on Availity Essentials and ProviderConnect. The page calls Availity the “preferred choice for direct data entry claim submissions.” If you send batches, our electronic claims submission page explains the handoff.

How fast should Carelon pay? The state report lists contract standards: clean claims paid within 14 days, and all claims adjudicated within 30 days. Maryland’s prompt-pay law also reaches the Medicaid mental health ASO. The Maryland Insurance Administration prompt-pay page says clean claims must be paid within 30 days.

Where Maryland claims go wrong

These five patterns come up again and again in Maryland Medicaid behavioral health billing. Each is visible in Carelon’s 2026 notices or the state report.

1. Wrong track. A specialty claim sent to an MCO, or the reverse, will not pay. Check the member’s plan and service type first.
2. Authorization mismatch. A January 22, 2026 alert on Carelon’s provider alerts page covers “No Authorization on File” denials caused by an authorization class and service code mismatch. Match both before you appeal. Our denied claims and appeals page covers the follow-up.
3. Old transition claims. The state report counted 216,466 outstanding claims as of July 31, 2025. It also described data transfer problems from Optum. Keep an aging report and recheck anything past 30 days.
4. Rendering provider links. The report lists rendering provider associations among the fixed issues. Confirm each clinician is linked to your group in the portal.
5. Medication management visits. The same alerts page lists a July 8, 2026 reminder on medication management authorization type of care. Psychiatrists should confirm the type of care before billing E/M visits.

A payment platform change is also coming on October 19, 2026.

Maryland Medicaid behavioral health billing checklist

Use this list to keep your Maryland Medicaid behavioral health billing on track.

1. Confirm your ePREP profile, group links and revalidation status.
2. Register for the Carelon Provider Digital Front Door.
3. Verify eligibility and plan type before each new patient.
4. Match authorization class and service code to every claim line.
5. Review psychotherapy CPT codes and diagnostic evaluation codes against the fee schedule for your license type.
6. Keep a claims aging report and review it weekly.

For state-specific Medicaid code quirks, our Medicaid HCPCS guide shows why the same code can mean different things by state. Unfamiliar terms? The Medicaid billing glossary defines them.

Maryland Medicaid behavioral health billing FAQ

Short answers on Maryland Medicaid behavioral health billing follow.

Do I enroll in ePREP or register with Carelon first?

Start with ePREP. The state guide says new Medicaid providers register with the ASO after they receive a provider number. Confirm the current order on the Carelon “Join the Network” page.

Does therapy for mild anxiety go to Carelon?

Per the state’s coverage page, mild conditions go through HealthChoice MCOs. Serious mental illness and substance use disorder are carved out to the specialty system. If a diagnosis sits in between, ask the MCO and Carelon before you bill.

How long does Carelon have to pay a clean claim?

The state report lists a 14-day contract standard for clean claims. The Maryland Insurance Administration says its prompt-pay law requires payment within 30 days.

Does MCM South bill Maryland Medicaid?

MCM South offers billing services to mental and behavioral health practices in Maryland. To talk through which payers and programs fit your practice, request a free consultation. Provider phone numbers for Maryland payers are in our Maryland and DC insurance contact guide.

Where MCM South Medical Billing Service Works

MCM South Medical Billing Service, LLC works exclusively with mental and behavioral health practices, including psychotherapists and psychiatrists, and bills out-of-network claims. We offer our services to practices in Maryland, and we also work with practices in Georgia, Massachusetts, Connecticut, Texas, Florida, New York, Colorado, Tennessee, North Carolina and Illinois. If you want to talk through your own billing, you can request a free consultation.