Medical Billing Terms E: EOB Billing, EPCS and External Review

EOB billing starts with the explanation of benefits (EOB), a payer statement that shows how a claim was processed and what the patient may owe. This page defines the EOB and the terms from encounter data to external review, including EOP, EPCS, EPO and ERISA. Each entry gives a plain definition, why it matters, an example, and an official source. MCM South Medical Billing Service, LLC works only in mental and behavioral health billing.

Last reviewed: October 10, 2026Sources linked at each term

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Billing Terms Glossary slide, Terms E: EOB Billing - MCM South Medical Billing Service, LLC

Glossary pages

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On this page (18 terms)

Encounter Data
Encounter Form
Encryption
Enrollment Follow-Up Call
EPCS
Epic
EPO (Exclusive Provider Organization)
E-Prescribing (eRx)
EPSDT
ERISA
Essential Health Benefits (EHB)
Established Patient (CPT)
Evernorth
Evidence-Based Practice in Psychology (EBPP)
Experian Health
Explanation of Benefits (EOB)
Explanation of Payment (EOP)
External Review

How to use these EOB Billing definitions

Use this page as a quick reference for Explanation of Benefits, from Encounter Data to External Review. Each entry gives a plain definition, why it matters to a mental health practice, and an official source. When a rule changes by payer or state, the entry says so, so confirm Explanation of Benefits details with the payer before you bill.

Checklist: put the eob billing definitions to work

Check the eob billing entries above before you send a claim that depends on them.
Share this eob billing page with front-desk and billing staff so everyone works from the same definitions.
When a payer letter mentions eob billing, find the matching entry and note the date you checked it.
Keep your eob billing notes next to your payer contracts, because a contract can define a term differently.
Ask the payer to confirm in writing how it applies eob billing before you change a workflow.
Train new staff on eob billing first, then move on to the rest of the glossary.
Log any eob billing question that comes up twice, then add the answer to your billing procedures.
Use the source links under the eob billing entries to confirm the current rule.
Print the eob billing entries you use most and keep them at the billing desk.
Review your eob billing notes each quarter, because payer and CMS rules change.

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Encounter Data

General (all payers)

Also called encounter claim; shadow claim

Definition: Records of services delivered under capitated arrangements that must be submitted even though payment is not per claim.
Why it matters: Missing encounter data can hurt rate setting and quality measurement.
Illustrative example: A capitated provider submits encounter claims to the plan.

Reference sourceCMS (Centers for Medicare & Medicaid Services)Medicaid.govchecked 10/9/26

CategoriesValue-Based Care Terminology Medicare & Medicaid Terms

Encounter Form

General (all payers)

Also called superbill form; charge ticket

Definition: A form or record of the services delivered in a visit that supports charge entry.
Why it matters: Helps make sure every service is captured for billing.
Illustrative example: A clinician completes the encounter form after each session.

Related termsCharge Capture Superbill

Reference sourceMGMAchecked 10/9/26

CategoriesClaims Processing

Encryption

General (all payers)

Also called data encryption; encryption at rest; encryption in transit

Definition: Scrambling data so it is unreadable without a key, protecting it in storage and during transmission.
Why it matters: Safe harbor for breach notification depends on proper encryption.
Illustrative example: A laptop with encrypted storage is lost and not treated as an unsecured PHI breach.

Reference sourceHHS (U.S. Department of Health and Human Services)HHS Office for Civil Rights (OCR)checked 10/9/26

CategoriesEHR & Healthcare Technology Terms Audits & Compliance

Enrollment Follow-Up Call

General (all payers)

Also called Follow-Up Call; payer follow-up; credentialing status call

Definition: Contacting a payer to confirm receipt, request status, or resolve missing items on an application.
Why it matters: Documented follow-up calls prevent files from sitting idle.
Illustrative example: A specialist logs the date, rep name, and reference number of each payer call.

Reference sourceNCQAchecked 10/9/26

CategoriesCredentialing & Enrollment

EPCS

General (all payers)

Also called electronic prescribing of controlled substances

Definition: Electronic prescribing of controlled substances, which requires additional identity proofing and security under DEA rules.
Why it matters: Psychiatrists prescribing controlled substances must use compliant systems where required.
Illustrative example: A psychiatrist uses two-factor authentication to sign an EPCS order.

Reference sourceNCPDPchecked 10/9/26

CategoriesEHR & Healthcare Technology Terms Behavioral Health Specific Terms

Epic

General (all payers)

Also called Epic Systems; Epic EHR

Definition: A large electronic health record vendor used mainly by hospitals and health systems. Listed for reference; not an endorsement or partnership.
Why it matters: Behavioral health departments in health systems often work in it.
Illustrative example: A hospital's outpatient psychiatry clinic documents in Epic.

Reference sourceEpicchecked 10/9/26

CategoriesEHR & Healthcare Technology Terms

EPO (Exclusive Provider Organization)

General (all payers)

Also called EPO plan

Definition: A plan that covers care only from in-network providers, generally without a referral requirement, except in emergencies.
Why it matters: Like HMOs, EPOs usually do not cover OON therapy.
Illustrative example: An EPO denies an OON claim as non-covered.

Reference sourceCMS (Centers for Medicare & Medicaid Services)checked 10/9/26

CategoriesEligibility & Benefits

E-Prescribing (eRx)

General (all payers)

Also called eRx; electronic prescribing

Definition: Sending prescriptions electronically from a prescriber's system to a pharmacy.
Why it matters: Prescribers such as psychiatrists rely on it; controlled substances have extra rules.
Illustrative example: A psychiatrist e-prescribes through the EHR.

Related termsEPCS NCPDP

Reference sourceNCPDPchecked 10/9/26

CategoriesEHR & Healthcare Technology Terms Behavioral Health Specific Terms

EPSDT

Medicaid (state-specific)

Also called Early and Periodic Screening, Diagnostic and Treatment

Definition: The Medicaid benefit for people under 21 that requires coverage of medically necessary services, including many behavioral health services.
Why it matters: Affects coverage and authorization arguments for children's services.
Illustrative example: A Medicaid plan reviews a child's request under EPSDT standards.

Related termsMedicaid Medical Necessity

Reference sourceMedicaid.gov CMS (Centers for Medicare & Medicaid Services)checked 10/9/26

CategoriesMedicare & Medicaid Terms Behavioral Health Specific Terms

ERISA

General (all payers)

Also called Employee Retirement Income Security Act

Definition: A federal law that sets standards for most employer-sponsored health and retirement plans, including claim and appeal procedures for those plans.
Why it matters: Sets appeal timelines and rights for many commercial members, and makes many self-funded plans exempt from state insurance law.
Illustrative example: An ERISA plan's denial letter cites internal and external review rights.

Reference sourceU.S. Department of Labor, EBSAchecked 10/9/26

CategoriesAudits & Compliance Eligibility & Benefits

Essential Health Benefits (EHB)

General (all payers)

Also called EHB; ACA essential health benefits; mental health essential benefit

Definition: Essential health benefits are categories of services that the Affordable Care Act requires many individual and small-group plans to cover. Mental health and substance use disorder services, including behavioral health treatment, are one of the categories.
Why it matters: It is why many marketplace plans cover therapy, but the exact services, limits, and prior authorization rules come from each state's benchmark plan and each plan's design.
Illustrative example: A practice checks a marketplace plan's summary to see how it covers outpatient therapy.

Reference sourceHHS (U.S. Department of Health and Human Services)checked 10/9/26

CategoriesEligibility & Benefits

Established Patient (CPT)

General (all payers)

Also called CPT established patient; established patient definition

Definition: Under CPT, an established patient is one who has received professional services from the physician or another physician of the exact same specialty and subspecialty in the same group practice within the past three years.
Why it matters: Established patient status decides whether you use 99211 to 99215. Payers may apply the rule differently for different specialties within a group.
Illustrative example: A patient seen last year by any psychiatrist in the group is established for the group's psychiatrists.

Reference sourceAMA, CPT code set overviewchecked 10/9/26

CategoriesClaims Processing

Evernorth

Private payer

Also called Evernorth Health Services

Definition: The health services business of The Cigna Group, which includes pharmacy and behavioral health services.
Why it matters: May administer behavioral health benefits for some plans.
Illustrative example: A provider is credentialed with a behavioral health administrator tied to Cigna.

Reference sourceEvernorthchecked 10/9/26

CategoriesBCBS, UHC & Commercial Payer Terms

Evidence-Based Practice in Psychology (EBPP)

General (all payers)

Also called EBPP; evidence-based practice; evidence-based treatment

Definition: Evidence-based practice in psychology is the integration of the best available research with clinical expertise in the context of patient characteristics and preferences.
Why it matters: Payers, accreditors, and value-based programs increasingly ask for evidence-based treatments. Document the approach and why it fits the patient.
Illustrative example: A therapist notes that a client's plan uses a research-supported treatment for the diagnosis and records progress with a standard measure.

Reference sourceSociety of Clinical Psychology (Division 12, American Psychological Association)checked 10/9/26

CategoriesBehavioral Health Specific Terms Quality & Risk Adjustment Terms

Experian Health

General (all payers)

Also called Experian Health clearinghouse

Definition: A health care technology business offering claim management, eligibility, and patient access tools. Listed for reference; not an endorsement or partnership.
Why it matters: Appears in payer and vendor lists.
Illustrative example: A hospital uses Experian Health for eligibility.

Reference sourceExperian Healthchecked 10/9/26

CategoriesEDI & Clearinghouse Terms

Explanation of Benefits (EOB)

General (all payers)

Also called EOB; explanation of benefits statement

Definition: A statement a payer sends the member, and sometimes the provider, that explains how a claim was processed and what the member owes.
Why it matters: Patients use it to check what they owe, and practices use it to reconcile balances.
Illustrative example: A patient brings an EOB showing $30 patient responsibility.

Reference sourceCMS (Centers for Medicare & Medicaid Services)checked 10/9/26

CategoriesPayment & Reimbursement Patient Financial Responsibility Terms

Explanation of Payment (EOP)

General (all payers)

Also called EOP; provider remittance statement

Definition: A payer's provider-facing statement explaining how claims were paid, similar to a remittance advice in paper or portal form.
Why it matters: Some payers call the remittance an EOP.
Illustrative example: A practice downloads an EOP from the payer portal.

Reference sourceCMS (Centers for Medicare & Medicaid Services)checked 10/9/26

CategoriesPayment & Reimbursement

External Review

General (all payers)

Also called independent review organization; IRO review

Definition: A review by an independent third party of a plan's denial, often available for medical necessity denials after internal appeal.
Why it matters: Can overturn plan decisions, including some behavioral health denials.
Illustrative example: A member requests external review after an internal denial.

Reference sourceCMS (Centers for Medicare & Medicaid Services)U.S. Department of Labor, EBSAchecked 10/9/26

CategoriesDenials & Appeals

Quick answer: EOB Billing

What is an explanation of benefits?

Explanation of Benefits (EOB) is a statement a payer sends the member, and sometimes the provider, that explains how a claim was processed and what the member owes. Patients use it to check what they owe, and practices use it to reconcile balances.

Frequently asked questions: EOB Billing

What is an Explanation of Payment?

Explanation of Payment (EOP) is a payer's provider-facing statement explaining how claims were paid, similar to a remittance advice in paper or portal form. Some payers call the remittance an EOP.

What is EPCS?

Electronic prescribing of controlled substances, which requires additional identity proofing and security under DEA rules. Psychiatrists prescribing controlled substances must use compliant systems where required.

What is an external review?

External Review is a review by an independent third party of a plan's denial, often available for medical necessity denials after internal appeal. Can overturn plan decisions, including some behavioral health denials.

Related resources

Where MCM South works

MCM South serves psychotherapists and psychiatrists in ten states: Georgia, Massachusetts, Connecticut, Texas, Florida, New York, Colorado, Tennessee, North Carolina and Illinois.

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