Coding for New Providers: Common Errors During the First 90 Days

Starting a new medical practice is exciting, but the first 90 days after credentialing can quietly determine whether your revenue cycle starts strong or struggles under avoidable denials. Many newly enrolled providers assume that once credentialing is approved, payments will flow smoothly. Unfortunately, that’s rarely the case.

From supervision rule violations to place-of-service (POS) errors and payer enrollment mismatches, early-stage billing mistakes can delay reimbursements, trigger compliance risks, and create cash flow gaps that are difficult to recover from.

In this guide, we’ll explore the most common coding and billing errors new providers face during the first 90 days – and how to prevent them.

Why the First 90 Days Are High-Risk for Revenue

The first 90 days after a provider is credentialed are operationally complex. While approval from payers may be finalized, backend systems often lag. Enrollment data may not be properly linked. Provider NPIs may not be mapped correctly in clearinghouses. Fee schedules may not be updated.

This gap between credentialing approval and full billing activation is where most denials occur.

New providers often experience:

Claims denied as “provider not enrolled.”
Incorrect reimbursement due to outdated fee schedules.
Claims are billed under the wrong supervising physician.
Delays due to incorrect place-of-service codes.
Incident-to billing rejections.

These issues are not always coding knowledge problems; they are startup process errors. And they can significantly impact cash flow during a time when overhead costs are already high.

Billing After Credentialing: Where Things Go Wrong

Credentialing approval does not automatically mean a provider is ready to bill.

One of the most common billing mistakes in new practices is submitting claims before payer systems fully activate the provider’s enrollment. Even a few days of premature billing can result in mass denials that must later be reprocessed.

Common enrollment-related errors include:

Provider linked to the wrong group tax ID.
Incorrect billing: NPI used instead of rendering NPI.X
The payer portal is not updated with the supervising physician.
Clearinghouse records are not aligned with payer data.
Retroactive effective dates were not applied correctly.

If claims are submitted before systems synchronize, payers may deny them under “provider not recognized” or “not credentialed on date of service.” Many practices assume these denials can be easily corrected. However, resubmissions, appeals, and corrected claims add weeks, sometimes months, to reimbursement timelines.

Supervision Rules That Trigger Denials

Supervision errors are among the most misunderstood issues in new provider billing. Newly hired nurse practitioners (NPs), physician assistants (PAs), and other non-physician providers must follow specific CMS and payer supervision guidelines. Failing to meet these requirements can result in denials or compliance risks.

Key Supervision Types

Supervision Type	Description	Common Risk
Direct Supervision	Supervising physician present in the office suite and immediately available	Physician not documented or not on-site
General Supervision	Physician oversight, but not required onsite	Incorrect billing under the physician
Incident-To Billing	Services billed under the supervising physician at 100% rate	Not meeting established patient or plan-of-care rules

One of the most frequent first-90-day billing mistakes involves improper incident-to billing. To qualify:

If these requirements are not met, payers may downcode, deny, or flag the claim for audit. New practices often assume that billing under the supervising physician guarantees higher reimbursement. However, incorrect supervision coding can expose the practice to compliance risk and repayment demands.

Place-of-Service (POS) Coding Errors

Place-of-service codes directly impact reimbursement rates. Using the wrong POS code is a common and costly mistake during startup.

For example:

Reimbursement varies significantly between office-based and facility-based settings. Incorrect POS coding can lead to underpayment, overpayment, or automatic denials. Telehealth has added another layer of complexity. Depending on payer guidelines, telehealth claims may require specific POS codes combined with appropriate modifiers such as 95 or GT. Incorrect combinations frequently result in claim rejections.

New providers transitioning between multiple service locations are especially vulnerable to these mistakes during their first 90 days.

Common First-90-Day Errors and Their Impact

The following table highlights frequent startup billing mistakes and their financial consequences.

Error Type	Why It Happens	Financial Impact
Claims submitted before enrollment activation	Miscommunication between the credentialing and billing teams	Mass denials, delayed cash flow
Incorrect supervision documentation	Lack of clarity on CMS guidelines	Downcoding or compliance exposure
Wrong POS code	Transition between locations or telehealth confusion	Underpayment or denial
Rendering NPI mismatch	Clearinghouse setup errors	Claim rejection
Billing under the supervising physician improperly	Attempt to maximize reimbursement	Audit risk and recoupment

These errors often compound. A single setup issue can affect dozens of claims before it’s identified.

How to Protect Revenue During Startup

Preventing claim denials in the first 90 days requires structured coordination between credentialing, billing, and compliance teams.

A proactive startup billing strategy includes:

Enrollment Verification Before First Claim Submission
Confirm payer portal activation, effective dates, group linkage, and clearinghouse alignment before submitting claims.
Supervision Policy Review
Ensure documentation templates clearly capture supervising physician involvement. Educate providers on incident-to billing requirements.
Place-of-Service Audit
Verify POS codes for every service location and telehealth setup. Confirm payer-specific requirements.
Internal Claim Scrubbing
Implement pre-submission claim audits to catch NPI mismatches, modifier errors, and supervision inconsistencies.
Denial Trend Monitoring
Track early denials closely. The first 30 claims often reveal systemic setup issues.

Many new practices underestimate how complex revenue cycle management becomes immediately after credentialing. Having oversight during this transition phase can protect thousands of dollars in revenue.

Why New Providers Struggle Without Structured RCM Support

New practice owners are often focused on:

Billing oversight may not receive immediate attention – but revenue disruption in the first quarter can significantly strain operations.

The most common pattern seen in startup practices is reactive billing. Claims are submitted, denials occur, and corrections happen afterward. This reactive approach creates unnecessary administrative burden.

A structured, proactive revenue cycle strategy reduces denials before they occur.

How MaxRemind Helps New Providers Avoid Costly Mistakes

At MaxRemind, we understand that the first 90 days after credentialing are critical to a practice’s financial stability.

Our team supports new providers by:

Verifying payer enrollment activation before billing begins
Aligning credentialing data with clearinghouse systems
Reviewing supervision requirements to ensure compliance
Auditing place-of-service configurations
Monitoring early claim submissions for denial patterns
Implementing structured revenue cycle workflows

Instead of reacting to denials, we help practices prevent them.

New providers benefit from having experienced billing and credentialing professionals overseeing the transition from enrollment to active reimbursement. By ensuring clean claim submission from day one, practices can protect cash flow and focus on patient care rather than administrative rework.

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Final Thoughts

The first 90 days of billing after credentialing represent a high-risk window for new providers. Supervision errors, enrollment mismatches, and place-of-service coding mistakes can quietly drain revenue before the practice stabilizes. The good news is that these mistakes are preventable.

With proper coordination between credentialing, billing, and compliance teams – and with structured oversight – new practices can avoid early denials, maintain steady cash flow, and establish a strong revenue cycle foundation. Starting a new practice is challenging enough. Your billing process should support growth, not slow it down.

If you’re launching a new practice or onboarding new providers, MaxRemind can help ensure your first 90 days are financially stable, compliant, and denial-resistant.

Protect Your Revenue from Day One

Claim your free trial with MaxRemind to prevent early denials, ensure supervision compliance, and keep your new provider billing on track.

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FAQs

Why are claims getting denied during the first 90 days after credentialing?: Claims are often denied during the first 90 days because payer systems may not be fully updated, provider enrollment may not be properly linked to the group, or billing may begin before activation is complete. Supervision errors, NPI mismatches, and incorrect place-of-service (POS) codes are also common causes of early denials.
Can new providers bill independently right after credentialing approval?: Not always. Even after credentialing approval, payers must fully activate the provider in their system. In addition, non-physician providers such as NPs and PAs must follow specific supervision and incident-to billing rules. Billing independently without verifying activation and supervision requirements can result in claim rejections.
What are the most common supervision mistakes in new provider billing?: The most common supervision errors include billing incident-to services without meeting CMS requirements, failing to document supervising physician involvement, and submitting claims when the supervising physician was not onsite (if direct supervision is required). These mistakes can lead to denials or compliance risks.
How does place-of-service (POS) coding affect reimbursement?: Place-of-service codes directly impact reimbursement rates. Using the wrong POS, such as billing office (POS 11) instead of outpatient hospital (POS 22), or incorrect telehealth POS codes, can lead to underpayment, overpayment, or claim denials. Accurate POS coding is critical during the startup phase.
How can new practices prevent billing errors in the first 90 days?: New practices can prevent early billing errors by verifying payer activation before submitting claims, auditing supervision documentation, confirming correct POS codes, monitoring denial trends, and implementing pre-submission claim reviews. Partnering with an experienced revenue cycle management team like MaxRemind can also help ensure clean claims and protect early cash flow.