10 Common Internal Medicine Billing Errors That Trigger Denials (And How to Fix Them)

Accurate billing is essential for maintaining profitability in internal medicine billing services.

Yet, even experienced practices face denials, audits, and payment delays due to avoidable coding and documentation mistakes.

This guide lists the most frequent billing errors in internal medicine, explains why they occur, and offers specific solutions to prevent revenue loss and compliance risks. For a complete workflow, read our internal medicine billing guide.

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✔ Correct E/M code selection based on MDM or time (99213–99215)
✔ Proper modifier usage (-25, -59, -95) to reduce claim rejections
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What Are the Most Common Internal Medicine Billing Errors?

Internal medicine practices often face denials due to recurring billing issues. These include incorrect CPT codes, lack of documentation, modifier misuse, and outdated ICD-10 codes.

Common Errors

Error Type	Example CPT/Modifier	Common Impact	Root Cause
E/M undercoding or overcoding	99213 vs 99214	Audit risk, lost revenue	Inconsistent documentation
Modifier -25 misuse	99213 + 11720	Denial for unbundling	No separate note for procedure
Chronic care time misreporting	99490	Rejection by Medicare	Missing time or consent
ICD-10 code inaccuracy	I10 vs I11.9	Rejection for lack of specificity	Non-updated code list
Cloned documentation	SOAP templates reused	Audit trigger	EMR default behaviors
Wrong POS in telemedicine claims	02 vs 11	Telehealth claim denial	Ignoring payer-specific rules

You can compare internal medicine vs family practice billing differences to see how payer expectations vary.

The 10 most common medical billing denials and fixes.

How Does Incorrect E/M Code Selection Lead to Denials?

Incorrect selection of Evaluation & Management (E/M) codes remains a leading cause of claim denials in internal medicine. Since the 2021 AMA updates, coding must be based on either Medical Decision Making (MDM) or total time, and staying current with ongoing refinements is crucial in 2025.

• Undercoding: Billing 99213 for a 40-minute visit still results in significant revenue loss-now estimated between $45 to $70 per claim due to rising costs.
• Overcoding: Billing 99215 without thorough, supporting documentation continues to trigger stricter payer audits and potential recoupments.
• Inconsistent Method: Frequently switching between MDM and time-based coding without a clear justification increases denial risk and delays reimbursement.

Solution:

• Provide ongoing staff training on the latest 2025 E/M guidelines and payer-specific nuances.
• Leverage updated coding calculators and AI-assisted tools (such as AAPC’s 2025 coding resources) to ensure accuracy.
• Implement rigorous pre-bill audits focusing on high-volume E/M codes to catch errors before submission.

Note: Use official sources like the AMA CPT codebook and payer guidelines for accurate coding, and seek professional support for tailored advice. Regular audits help catch errors early. Note that financial estimates and payer practices vary, so these figures are general guidance, not exact predictions.

See the latest E/M coding changes for internists for full details on the updated guidelines.

Why Does Modifier Misuse Cause Reimbursement Loss?

Incorrect or missing modifiers, particularly -25, -59, -24, and -57, remain a leading cause of claim denials and revenue leakage.

Key Examples:

• Modifier -25: Required when billing an E/M service (e.g., 99214) with a separate procedure (e.g., 11721) on the same day.
• Modifier -59: Critical for distinct procedural services (e.g., 20610 and 96372) performed during the same encounter.

Top Reasons for Denials:

• Modifier -25: Claims denied when documentation fails to prove the E/M was separately identifiable from the procedure.
• Modifier -59: Denials occur if used incorrectly (e.g., unbundling bundled codes or ignoring CCI edits).

Solutions:

• Cross-check NCCI Edits before claim submission.
• Document thoroughly: Maintain separate notes for modifier-25 cases and anatomic specificity for modifier -59.
• Conduct monthly audits focusing on high-risk modifiers to catch errors proactively.

Note: Payer policies vary; always verify requirements with individual contracts or Medicare Administrative Contractors (MACs) guidelines.

How Do Documentation Gaps Lead to Claim Denials?

Poor documentation remains a primary reason for claim rejections, particularly for chronic condition management, annual wellness visits (AWVs), and high-level E/M services.

Common Problems:

• No clear medical necessity: Failing to connect diagnoses to treatment plans.
• Incomplete documentation: Missing essential elements like HPI, ROS, or exam findings.
• Template overuse: Relying too heavily on cloned or generic EMR notes.

Example:

Billing 99214 for stable hypertension without documenting:

• Medication changes
• Comorbid conditions (where two or more medical conditions exist simultaneously in a patient) affect care
• Specific risk factors

Leads to denials or downcoding to 99213.

Solution:

1. Use dynamic EMR templates that require diagnosis-specific details.

2. Implement documentation checks to ensure assessments justify each diagnosis.

3. Train providers on:

• Precise ICD-10 coding (e.g., I11.0 vs I11.9)
• Current E/M documentation requirements

4. Conduct pre-submission audits to catch missing elements.

Note: Most payers strictly enforce documentation rules – regular reviews can prevent significant revenue loss.

What Billing Errors Occur in Chronic Care Management (CCM)?

CCM codes (99490, 99487, 99489) are frequently denied due to documentation oversights. Strict Medicare requirements mean even minor errors can trigger rejections.

Top Denial Reasons:

1. Time Tracking Issues:

• 99490 requires at least 20 minutes per month.
• 99487 requires at least 60 minutes of complex care.

2. Missing Consent Documentation:

• No signed or verbal consent on file.
• Failure to document cost-sharing discussion.

3. Ineligible Conditions:

• Fewer than two chronic conditions.
• Conditions not expected to last at least 12 months.

Example Denial Scenario:

Billing 99490 without:

• Dated patient consent
• Documented care plan
• Proof of 20 or more minutes of care

Leads to automatic denial.

Prevention Strategies:

1. Use EHR timers to track care time automatically.

2. Implement consent forms that meet Medicare requirements.

3. Monthly chart audits to verify:

• Proper condition documentation
• Code-level time requirements
• No duplicate billing

Note: Medicare updates CCM rules annually – stay current to avoid denials.

What Are the Common Pitfalls in Annual Wellness Visit (AWV) Billing?

Many providers mistakenly bill AWVs (G0438, G0439) as routine physical exams (99381-99397), leading to claim denials and revenue loss.

Essential AWV Requirements:

• Personalized prevention plan with 5-10 year screening schedule.
• Comprehensive risk assessment, including cognitive and depression screening.
• Optional advance care planning (billable separately with 99497 if performed).

Frequent Billing Mistakes:

1. Using physical exam codes instead of AWV codes.
2. Missing required documentation elements.
3. Billing for ineligible Medicare patients.

Solutions:

• Staff education: Regular training on AWV coding specifics.
• Structured templates: CMS-aligned documentation checklists built into EHR.
• Eligibility checks: Verify Medicare Part B status prior to visit.
• Quality audits: Review random AWV claims monthly for compliance.

Note: AWV errors are a top audit target – proper documentation prevents denials and recoupments.

What Telehealth Billing Mistakes Lead to Denials?

Telehealth claims often get denied due to incorrect place-of-service codes or modifier errors that vary by payer.

Common Errors:

• Using POS 11 (office) instead of POS 02 (telehealth).
• Forgetting required modifiers (95 for commercial payers, GT for Medicare).
• Billing CPT codes not approved for virtual visits.

Solution:

• Create payer-specific reference guides for POS and modifier rules.
• Build telehealth templates that include consent and auto-populate modifiers.
• Use claim scrubbing tools to catch errors before submission.

Note: Most telehealth denials stem from simple POS/modifier mistakes – double-check these first.

Learn whether clearinghouse vs. direct billing is better for reducing denials.

How to Avoid Duplicate Billing and Upcoding Errors?

Duplicate claims and improper code selection trigger costly denials and increase audit risks for medical practices.

Frequent Mistakes:

1. Duplicate Charges:

• Submitting 99213 multiple times for one visit date.
• Billing both an office visit and procedure without modifier -25.

2. Upcoding Problems:

• Using 99215 without meeting medical necessity requirements.
• Selecting higher-level codes that don’t match the documentation.

Upcoding errors often stem from a lack of clarity on CPT level selection. Review the core internist billing processes better to understand the correct use of 99213–99215.

Prevention Methods:

1. Automated Claim Review:

• Use Medical Billing Software for Internal Medicine Practices to catch duplicate submissions.
• Enable EHR alerts for same-day duplicate charges.

2. Documentation Checks:

• Verify code levels against the provider’s MDM notes.
• Require physician review for all level 5 visits.

3. System Controls:

• Implement EHR blocks for duplicate date-of-service entries.
• Set coding review thresholds for high-level E/M services.

Important: Regular coding audits can identify 85% of duplicate billing errors before claims submission.

How Can Internal Medicine Practices Prevent Billing Errors in 2025?

Proactively reduce denials and audits with these 2025 best practices:

✅ Monthly Coding Audits: Target high-risk areas: E/M levels, modifiers (-25, -59), and CCM documentation.

Medical billing compliance checklist to ensure adherence to Medicare and commercial payer rules.

✅ AI Claim Scrubbers: Use tools like Availity, ClaimCheck to flag missing modifiers/bundling errors pre-submission.

✅ Staff Training Updates: Annual AAPC/AHIMA recertification + quarterly CMS webinar reviews.

✅ Documentation Compliance Logs: Track CCM time logs, AWV checklists, and telehealth consent forms.

✅ Payer-Specific SOPs: Align billing rules with Medicare/MAC and commercial payer policies.

Note: Practices using these methods reduce denials by 30-50% (MGMA data).

Understand the difference between medical billing vs. revenue cycle management for a holistic approach.

Frequetly Asked Questions (FAQ’s)

What are the most common billing errors in internal medicine?

The most frequent errors include incorrect E/M coding, modifier misuse, missing documentation, outdated ICD-10 codes, and improper time tracking for CCM.

How does incorrect E/M code selection cause denials?

Using the wrong code level (e.g., 99213 instead of 99214) without supporting documentation leads to audits or payment reductions under AMA’s 2021+ guidelines.

What documentation is required for CPT 99490 (CCM billing)?

Medicare requires at least 20 minutes of documented care per month, patient consent, and documentation of two or more chronic conditions.

When should you use modifier -25 in internal medicine billing?

Use modifier -25 when a significant, separately identifiable E/M service is performed on the same day as a procedure.

What causes telemedicine billing denials in internal medicine?

Denials often result from incorrect POS codes (e.g., POS 11 instead of POS 02) or missing modifiers like 95 or GT.

How can cloned documentation lead to billing audits?

Copy-pasted SOAP notes can trigger fraud flags, especially if identical phrases appear across multiple patient visits without clinical variation.

What’s the difference between AWV and a routine physical exam?

AWVs (G0438, G0439) focus on prevention planning and risk assessments, while routine exams (99381–99397) include physical evaluations and are not covered under Medicare for wellness.

Why are ICD-10 code errors common in internal medicine claims?

Payers deny claims when codes lack specificity (e.g., I10 vs I11.9), are outdated, or are not linked to documented services.

How do internal audits reduce billing denials?

Monthly coding audits help identify undercoding, upcoding, modifier misuse, and missing elements before claim submission, improving first-pass acceptance rates.

What tools help prevent billing errors in internal medicine?

AI-powered claim scrubbers, EHR-integrated timers, audit dashboards, and CPT code calculators are effective tools for error detection.

Can using the wrong modifier cause a claim denial?

Yes. Using modifier -59 or -25 incorrectly can lead to automatic denials due to payer bundling policies and NCCI edit conflicts.

How can internal medicine practices stay compliant with Medicare billing rules?

Follow CMS and MAC guidelines, conduct regular staff training, use structured EMR templates, and document all times, consent, and clinical decisions accurately.