Authorization in Medical Billing: A Complete Guide for Providers

Authorization in medical billing is the process of obtaining approval from a patient’s health plan for certain services, procedures, equipment, or medications before they are provided or billed. The payer reviews the request against its coverage and medical-necessity requirements and decides whether the requested care meets its authorization criteria.

For healthcare providers, authorization is more than an administrative task. Missing an authorization, requesting it for the wrong service, allowing it to expire, or failing to document the approval correctly can result in delayed treatment, claim denials, additional staff work, and lost reimbursement.

Authorization requirements also vary considerably among Medicare, Medicare Advantage, Medicaid, commercial insurance plans, and individual benefit products. A service that requires authorization for one patient’s plan may not require it for another.

For that reason, a reliable authorization workflow should start before treatment and continue through claim submission and payment reconciliation.

What Is Authorization in Medical Billing?

Authorization is a payer’s review and approval process for healthcare services subject to utilization-management requirements.

A physician or other authorized party submits information explaining the requested service and, where required, the patient’s clinical condition. The payer then determines whether the request meets its coverage criteria.

Depending on the plan, the payer may:

• Approve the request
• Deny the request
• Ask for additional information
• Approve only part of the requested service
• Authorize a specific number of visits or units
• Limit approval to a defined period
• Require another level of review

Prior authorization is intended to occur before the service is provided.

CMS describes Medicare prior authorization as a process in which a provider or supplier submits the request and supporting medical documentation before the service is rendered and receives an affirmed or non-affirmed decision from the Medicare Administrative Contractor, or MAC.

Why Authorization Matters in Medical Billing

Authorization affects several points in the revenue cycle.

A treatment may be medically appropriate, correctly coded, and fully documented, but the claim can still face payment problems if the patient’s plan required authorization and the provider did not complete the required process.

Authorization management helps practices:

• Confirm payer requirements before services
• Reduce preventable authorization-related denials
• Identify documentation requirements early
• Confirm approved procedures and units
• Track authorization dates
• Avoid scheduling services outside approved periods
• Maintain proof of authorization
• Support cleaner claim submission

However, authorization should not be confused with a guarantee of payment.

A claim may still need to satisfy eligibility, benefit, documentation, coding, coverage, medical-necessity, and other payer requirements.

CMS similarly explains that its prior authorization programs do not replace existing medical-necessity or documentation requirements. Instead, required information is reviewed earlier in the payment process.

Types of Authorization in Medical Billing

The terminology used by health plans is not completely standardized. Still, billing teams commonly encounter several authorization situations.

Authorization Type	When It Occurs	Main Purpose
Prior authorization	Before the service	Obtain payer approval before treatment
Pre-authorization	Before the service	Often another term for prior authorization
Concurrent authorization	During ongoing treatment	Approve continued services or additional days/visits
Retro authorization	After the service	Request authorization after treatment when the payer permits it
Referral authorization	Before certain specialist care	Confirm plan-required referral or specialist access

Requirements for each category depend on the patient’s health plan and payer policy.

Prior Authorization

Prior authorization, sometimes called preauthorization or precertification, is the most common form.

The provider checks whether the planned service requires payer approval and submits the required clinical and administrative information before treatment.

Services that may be subject to authorization can include certain:

• Imaging studies
• Surgeries
• Procedures
• Durable medical equipment
• Specialty services
• Therapies
• Medications
• Hospital services

The exact list depends on the payer, plan, place of service, benefit structure, and other factors.

Never assume a procedure requires or does not require authorization simply because another payer handles it a particular way.

Pre Authorization in Medical Billing

Pre authorization in medical billing generally refers to authorization obtained before the service occurs.

In daily billing operations, the terms “preauthorization” and “prior authorization” are often used for similar payer-review processes.

Staff should still use the terminology and workflow required by the specific health plan.

Concurrent Authorization

Concurrent authorization may apply when treatment is already underway but continued services require payer review.

For example, an approved treatment plan may cover an initial number of visits. The payer may require additional clinical information before approving more sessions.

Concurrent review can therefore affect:

• Additional therapy visits
• Continued inpatient care
• Extended treatment courses
• Additional units
• Ongoing specialty services

The authorization team should track approved limits before they are exhausted.

Retro Authorization in Medical Billing

Retroactive authorization, commonly shortened to retro authorization, involves requesting payer approval after a service has already been delivered.

It is important to understand that retro authorization is not a universal solution for a missed prior authorization.

Some plans may permit retrospective requests under limited circumstances, while others may not.

Possible situations can include payer-specific exceptions involving emergency circumstances, administrative problems, coverage updates, or other conditions defined by the health plan.

Providers should verify the payer’s policy rather than assuming a missed authorization can be corrected later.

Prior and Retro Authorization in Medical Billing: Key Difference

The main difference between prior and retro authorization in medical billing is timing.

Prior authorization occurs before treatment. Retro authorization is requested after treatment has already occurred.

Consider this example.

A physician orders a procedure scheduled for next week. The insurer’s policy requires prior approval. The practice submits the clinical records, receives authorization, and performs the service within the approved dates.

That is prior authorization.

Now imagine the same service is completed before anyone discovers that payer approval was required. The office contacts the insurer afterward and asks whether retrospective authorization is available.

That is a retro authorization request.

The payer may approve it, review it under special rules, or reject it depending on plan requirements.

For this reason, retro authorization should be considered an exception process rather than a substitute for proper pre-service verification.

How the Medical Billing Authorization Process Works

A well-managed authorization process usually follows seven steps.

Step 1: Verify Patient Eligibility

Confirm that the patient’s coverage is active for the expected date of service.

Check:

• Plan information
• Member ID
• Effective dates
• Payer
• Network status where relevant
• Benefit information

Eligibility should be verified close enough to the service date to reduce the risk of using outdated coverage information.

Step 2: Determine Whether Authorization Is Required

Check the patient’s specific plan requirements for the planned service.

Authorization requirements can depend on several details, including:

• Procedure or service
• Diagnosis or clinical indication
• Site of service
• Rendering provider
• Ordering provider
• Units or frequency
• Benefit plan

Document how the requirement was checked.

Step 3: Collect Required Information

A prior authorization request may require administrative and clinical information.

Common documentation can include:

• Patient demographics
• Member information
• Ordering provider information
• Rendering provider information
• Requested service
• Relevant procedure codes
• Diagnosis information
• Medical records
• Physician notes
• Test results
• Previous treatment history

Only submit information relevant to the payer’s requirements and the requested service.

Step 4: Submit the Authorization Request

Requests may be submitted through a payer portal, electronic system, fax, telephone workflow, or another payer-approved channel.

Record:

• Submission date
• Reference number
• Requested service
• Requested dates
• Requested units
• Documents submitted
• Payer contact information

Good tracking becomes especially important when authorization remains pending close to the scheduled treatment date.

Step 5: Monitor the Request

Do not assume silence means approval.

Track the request until the payer issues a decision.

If additional records are requested, send them promptly and document the response.

Step 6: Verify the Approval Details

An approval number alone is not enough.

Review the entire authorization.

Confirm:

• Authorization number
• Approved service
• Approved procedure code when specified
• Number of approved units or visits
• Approved provider
• Approved facility or site of service
• Effective date
• Expiration date
• Other payer conditions

An authorization for the wrong service or wrong dates may not support the final claim.

Step 7: Connect the Authorization to Billing

The final claim should accurately reflect the service actually performed.

When required by the payer, ensure the authorization or reference information is available to the billing team and reported appropriately.

The authorization record should remain accessible in case the claim is later denied or reviewed.

Common Prior Authorization Denials

Prior authorization denials can occur before treatment or lead to claim problems after treatment.

Common causes include the following.

Missing Authorization

The service required prior approval, but no request was submitted.

This is one of the most preventable authorization problems.

Incomplete Clinical Documentation

The payer may not have enough information to determine whether the requested service meets its criteria.

Submitting a form without the required supporting records can delay or prevent approval.

Medical Necessity Criteria Not Met

The payer’s review may determine that the submitted information does not establish coverage or medical necessity under its applicable policy.

This does not necessarily mean the physician believes the service lacks clinical value. It means the request did not meet the payer’s applicable authorization criteria.

Authorization Expired

A valid authorization may have been obtained, but the service occurred outside the approved date range.

Wrong Procedure or Service

The service performed may differ from the one approved.

Authorization staff and clinical teams should communicate when the treatment plan changes.

Incorrect Number of Units

The payer may authorize a limited number of visits, treatments, or units.

Claims beyond that limit can create reimbursement issues if additional authorization was required.

Provider or Facility Mismatch

Authorization may be associated with a particular rendering provider, facility, network, or location under the applicable payer requirements.

Eligibility Changed

Authorization may have been obtained while one plan was active, but the patient’s coverage changed before the service.

This is why eligibility should be rechecked when appropriate, especially for services scheduled well after the original authorization request.

Authorization Denial vs. Claim Denial

These are related but different.

An authorization denial occurs when a payer does not approve a requested service during the authorization process.

A claim denial occurs after a claim is submitted for payment.

For example, a payer may approve prior authorization, but the final claim can still encounter problems involving eligibility, coding, billing information, benefit limitations, or failure to meet another payment requirement.

Likewise, a service performed without required authorization may later result in a claim denial.

Authorization and claims management should therefore work together instead of operating as isolated departments.

Does Prior Authorization Have a CPT or ICD-10-CM Code?

There is no single CPT, HCPCS, or ICD-10-CM code that means “prior authorization.”

CPT and HCPCS codes identify procedures, professional services, supplies, equipment, drugs, and other reportable items or services.

ICD-10-CM codes report diagnoses and other health conditions relevant to the claim.

Those codes can be important during authorization because the payer needs to understand what service is being requested and why.

However, code submission alone does not establish coverage or authorization.

Code selection must reflect the documentation and follow applicable coding guidance and payer requirements.

Important 2026 CMS Prior Authorization Changes

Providers should be aware that federal prior authorization requirements are changing.

Under the CMS Interoperability and Prior Authorization Final Rule, CMS identified Medicare Advantage organizations, state Medicaid and CHIP fee-for-service programs, Medicaid managed care plans, CHIP managed care entities, and Qualified Health Plan issuers on Federally Facilitated Exchanges as impacted payers for various provisions of the rule.

Beginning in 2026, impacted payers covered by the applicable denial-reason requirement must provide a specific reason when they deny prior authorization for affected non-drug items and services, regardless of whether the request arrived through a portal, fax, email, mail, or phone.

For applicable impacted payers other than QHP issuers on the Federally Facilitated Exchanges, CMS also requires decisions within:

72 hours for expedited requests

7 calendar days for standard requests

These operational provisions began in 2026.

Practices should note that payer type and service category matter. These CMS requirements should not be treated as universal authorization deadlines for every health plan or every drug.

Electronic Prior Authorization in 2027

A major technology change is also approaching.

CMS requires impacted payers to implement Prior Authorization APIs beginning in 2027 for applicable non-drug items and services.

These APIs are designed to allow systems to communicate:

• Whether authorization is required
• Documentation requirements
• Authorization requests
• Approval decisions
• Authorization duration
• Denial decisions
• Specific denial reasons
• Requests for more information

CMS states that these Prior Authorization API requirements generally begin January 1, 2027.

For medical practices, this makes EHR and practice-management system readiness increasingly important.

Authorization teams should begin discussing electronic prior authorization capabilities with technology vendors rather than waiting until workflow changes become mandatory for affected organizations.

Medicare Advantage Prior Authorization Protections

Medicare Advantage has additional utilization-management requirements that providers should understand.

CMS requires coordinated care plans to provide a minimum 90-day transition period for an enrollee undergoing an active course of treatment when that person switches to a new Medicare Advantage plan. During that transition period, the new plan may not require prior authorization for the active course of treatment.

CMS also requires an approved prior authorization for a course of treatment to remain valid for as long as medically reasonable and necessary under applicable criteria, the patient’s medical history, and the treating provider’s recommendation.

These protections are Medicare Advantage-specific and should not be generalized to all commercial health plans.

How to Prevent Authorization-Related Denials

Authorization problems are easier to prevent than repair after claim submission.

Check Requirements Before Scheduling

Where possible, determine authorization requirements before a high-cost or scheduled service is finalized.

Verify the Exact Plan

Do not rely only on the insurance company’s name.

Different plans from the same insurer can have different requirements.

Build Authorization Checkpoints

Create checkpoints at:

• Scheduling
• Eligibility verification
• Authorization submission
• Pre-service review
• Claim preparation

Multiple checkpoints reduce dependence on one staff member catching every issue.

Maintain a Central Authorization Record

Track authorization information in a location accessible to scheduling, clinical, front-office, and billing staff.

Use Expiration Alerts

Set reminders for authorizations approaching their expiration date or approved-unit limit.

Review Changes in Treatment

If the physician changes the procedure, number of visits, location, or other important details, determine whether the existing authorization still applies.

Track Denial Patterns

Review recurring authorization denials by:

• Payer
• Service
• Provider
• Location
• Denial reason
• Staff workflow

Patterns often reveal process problems that individual claim follow-up does not.

Example of Authorization in Medical Billing

Consider a patient scheduled for an advanced imaging procedure.

The billing team verifies active insurance and discovers that the patient’s plan requires prior authorization.

The provider submits the requested clinical documentation. The insurer approves the imaging service for a defined period and provides an authorization number.

Before the appointment, staff confirm that:

• Coverage is still active
• The service matches the approval
• The imaging facility is correct where required
• The authorization has not expired

The procedure is completed and the claim is submitted.

Now consider what happens if the procedure is rescheduled beyond the authorization expiration date.

The original approval may no longer apply.

The staff should review payer requirements and obtain an extension or new authorization when required rather than simply submitting the claim and hoping the original approval will be accepted.

This type of pre-service check can prevent avoidable denials.

Best Practices for Authorization Management

Healthcare practices can strengthen authorization workflows by creating clear accountability.

A strong process should include:

• Real-time or timely eligibility checks
• Payer-specific authorization verification
• Complete documentation collection
• Accurate procedure and diagnosis information
• Central authorization tracking
• Pending-request follow-up
• Expiration monitoring
• Unit and visit tracking
• Pre-service confirmation
• Denial root-cause analysis
• Appeal deadline tracking
• Regular staff training
• Payer-policy updates

Authorization management should also connect with eligibility verification, coding, scheduling, denial management, claims follow-up, and accounts receivable.

Treating authorization as an isolated front-office function creates gaps that often become billing problems later.

Frequently Asked Questions

What is authorization in medical billing?

Authorization in medical billing is a payer review process used for certain healthcare services before coverage or payment is considered. Providers may need to submit clinical and administrative information so the payer can determine whether the request meets applicable coverage requirements.

Is pre authorization the same as prior authorization?

The terms are commonly used to describe approval obtained before a healthcare service is provided. However, terminology and procedures can differ by payer, so providers should follow the requirements of the patient’s specific health plan.

What is retro authorization in medical billing?

Retro authorization is a request for payer authorization made after a service has already occurred. It is only available when permitted by the payer’s policy and should not be treated as a guaranteed solution for missing required prior authorization.

Does prior authorization guarantee insurance payment?

No. Authorization does not replace other claim requirements. Eligibility, benefits, documentation, coding, medical necessity, payer policy, claim accuracy, and other payment conditions may still affect reimbursement.

What causes prior authorization denials?

Common causes include incomplete documentation, failure to meet payer criteria, missing information, incorrect service details, expired approvals, authorization for the wrong provider or location, and requests that do not satisfy applicable coverage requirements.

Can a denied prior authorization be resubmitted?

Sometimes. The available options depend on the payer and reason for denial. A payer may allow additional information, resubmission, peer-to-peer review, reconsideration, or an appeal. Follow the specific instructions and deadlines in the denial notice.

How long does prior authorization take in 2026?

There is no single timeframe for every U.S. payer. Under CMS-0057-F, applicable impacted payers, excluding QHP issuers on the Federally Facilitated Exchanges for this timeframe provision, must make expedited decisions within 72 hours and standard decisions within seven calendar days for affected prior authorization requests.

What happens if a provider forgets prior authorization?

The provider should first verify the payer’s policy. Depending on the circumstances, options may include correcting an administrative error, providing additional information, requesting retro authorization when permitted, disputing the denial, or filing an appeal. Retro authorization is not available under every plan.