Internal medicine practices lose more revenue to E/M level selection, modifier 25 denials, and unbilled chronic care management than to almost any other cause. The right billing partner is the one that understands these three areas thoroughly—not necessarily the one with the longest service list.

Table of Contents

1. Who Publishes This List, and How We Ranked
2. Why Internal Medicine Billing Is Different
3. The 8 Best Internal Medicine Billing Companies
4. Frequently Asked Questions
5. Sources

Who Publishes This List, and How We Ranked

This list is published by RKR Prime, a medical billing and revenue cycle management company, and RKR Prime is ranked first on the list. We disclose this upfront so readers can evaluate the recommendations accordingly.

Every other company on this list is described using information published by those companies themselves, with sources provided at the end of the article. We have not independently audited their performance, and the descriptions should not be interpreted as guarantees of results. Where figures come from a company’s own marketing materials, we identify them as such.

We evaluated the companies against five criteria that matter specifically to internal medicine practices:

We deliberately excluded company size, years in business, and client counts from the scoring criteria. A small billing team with deep internal medicine expertise may be better suited to an internist than a large firm that treats every specialty the same way.

Why Internal Medicine Billing Is Different

Internal medicine billing presents several distinct challenges:

• Medicare-heavy payer mix: Many practices depend significantly on Medicare reimbursement.
• E/M coding complexity: Office visits rely heavily on evaluation and management codes rather than procedures.
• Unbilled chronic care services: Eligible chronic disease management services may be delivered without being billed.
• Same-day preventive and problem visits: Claims involving preventive visits and separately identifiable problem-oriented services are frequently scrutinized by payers.

The Code Families an Internal Medicine Biller Must Know

Important: Verify all codes against the current CPT and HCPCS code sets before using them. Code sets are updated annually.

Modifier 25 Is a Major Denial Risk

Modifier 25 identifies a significant, separately identifiable evaluation and management service performed on the same day as another procedure or service.

In internal medicine, this commonly occurs when:

• A patient raises a new medical concern during a Medicare Annual Wellness Visit.
• A problem-oriented visit includes vaccine administration.
• A follow-up visit includes a minor procedure.

Payers scrutinize modifier 25 because it is frequently misused. Two factors are particularly important:

1. The E/M service must be genuinely separate from the other service.
2. The documentation must independently support the E/M service rather than requiring the reviewer to infer its medical necessity.

A billing company should be able to explain its modifier 25 review process clearly during an initial consultation.

Two 2026 Updates That Affect Internal Medicine Billing

1. FY 2027 ICD-10-CM code updates

The FY 2027 ICD-10-CM code set took effect on October 1, 2026. The source material reports approximately 190 new diagnosis codes, 30 deleted codes, and four revised codes. Practices should review their electronic health record (EHR) code lists to avoid submitting outdated or invalid diagnosis codes.

2. Proposed CY 2027 Medicare Physician Fee Schedule changes

The proposed conversion factors are $33.17 for qualifying Advanced Alternative Payment Model (APM) participants and $32.84 for non-qualifying participants. These proposed figures represent reductions of approximately 1.19% and 1.68%, respectively, compared with 2026.

For Medicare-heavy internal medicine practices, improving the capture of services already delivered may help offset reimbursement pressure.

Both topics are covered in greater detail in our billing and revenue cycle management insights.

The 8 Best Internal Medicine Billing Companies in 2026

Company descriptions and pricing figures are based on the companies’ own published materials and have not been independently verified by RKR Prime.

1. RKR Prime

Best for: Independent internal medicine practices and provider groups that want to improve E/M coding accuracy and capture more eligible chronic care management revenue.

We rank ourselves first, and readers should consider that fact when evaluating this list. Here is what we recommend comparing when assessing RKR Prime against other billing companies.

Our internal medicine services focus on three key revenue opportunities:

• E/M level selection: Reviewing evaluation and management coding under the medical decision-making and total-time guidelines.
• Modifier 25 documentation: Reviewing same-day preventive and problem-oriented visits to ensure that claims are appropriately supported.
• Chronic Care Management: Identifying eligible services that are being delivered but not billed.

During an initial consultation, we can review your practice data to help identify which of these areas may be affecting revenue.

What RKR Prime offers:

• Pricing: Percentage of collections, with monthly volume tiers published on our pricing page.
• Contract: No long-term lock-in.
• Transition: A documented four-week plan covering the initial audit, parallel run, transition of legacy accounts receivable, and monthly review calls.
• Systems: Works within your existing EHR, without requiring a platform change.
• Reporting: Scheduled monthly reporting by provider and payer, with a named account manager.
• Services: Medical billing and coding, claims management, denial management, eligibility verification, and provider credentialing.

Request a free accounts receivable (A/R) analysis

Send your A/R aging report and three months of denial data. RKR Prime offers a written summary within three business days, including an assessment of potentially recoverable aged receivables.

2. Medical Billers and Coders (MBC)

Best for: Practices with 1–10 providers seeking published pricing and a defined transition timeline.

Medical Billers and Coders markets its services directly to small practices and provides public information about pricing and onboarding.

The company states that its pricing ranges from 5% to 8% of collections, with no upfront cost, and that transitions generally take four to six weeks.

MBC also states that outsourced billing can reduce small practices’ billing costs by 30–50%. Its services address issues such as staff turnover, complex payer requirements, and aging receivables.

Its internal medicine services are part of a broader multispecialty offering rather than a dedicated internal medicine service line. Practices particularly concerned about E/M coding and CCM revenue should ask how these areas are reviewed.

3. MediBill RCM

Best for: Internists looking for a billing company that focuses exclusively on their specialty.

MediBill RCM describes itself as a revenue cycle management company dedicated to internists.

The company publicly states that it has:

• A 98.2% clean claim rate.
• Certified E/M and CCM coders working with codes in the 99213–99215 and 99490 ranges.
• A nationwide flat-rate pricing model of 3.9%.

These are company-reported figures and should be independently evaluated. Ask how the clean claim rate is calculated, what sample it represents, and what services are included in the flat rate.

Its specialty-specific positioning and clearly stated pricing may appeal to practices seeking a focused billing partner.

4. Precision Practice Management

Best for: Established internal medicine practices seeking coders familiar with complex, multisystem patient presentations.

Precision Practice Management (PPM) offers a dedicated internal medicine revenue cycle management service.

Its approach emphasizes the complexity of internal medicine, where patients may present with conditions affecting multiple organ systems. Billing teams must understand the range of services and documentation involved.

Pricing is provided by quote.

5. Outsource Strategies International (OSI)

Best for: Practices that need to improve coding accuracy and reduce revenue loss caused by coding issues.

Outsource Strategies International offers internal medicine billing and coding services and describes a model combining AI tools with human coding expertise.

Its approach places particular emphasis on coding within the revenue cycle.

This may suit practices that already have reasonably effective collections follow-up but suspect they are losing revenue because claims are incorrectly coded or inadequately supported.

6. Medisys Data Solutions

Best for: Small internal medicine practices with limited in-house billing resources.

Medisys Data Solutions offers a named internal medicine billing service aimed at smaller practices.

The company highlights challenges such as limited administrative resources, frequent regulatory changes, and the coding accuracy required for internal medicine.

Pricing is provided by quote.

7. AnnexMed

Best for: Small to midsized practices comparing multispecialty billing providers.

AnnexMed provides end-to-end medical billing services for independent physicians, group practices, and specialty clinics.

Unlike companies focused specifically on internal medicine, AnnexMed offers a multispecialty approach.

Before choosing this provider, ask about its internal medicine billing volume, the experience of the team assigned to your practice, and its process for reviewing E/M coding and chronic care management claims.

8. EHR-Bundled Revenue Cycle Management

Best for: Practices already committed to a particular electronic health record platform and seeking an integrated billing solution.

Several EHR vendors offer billing and revenue cycle management services alongside their software platforms, including:

• Tebra, formerly Kareo
• athenahealth
• eClinicalWorks
• CureMD

The main advantage is integration. Practices can benefit from a single vendor, connected workflows, and a centralized support channel.

However, billing services may be closely tied to the selected platform, making it more difficult to change billing providers without also changing systems. These services may also be more platform-led than specialty-led.

EHR-bundled RCM can be a reasonable choice for practices that prioritize simplicity and integration. Practices struggling specifically with unbilled chronic care management should confirm whether the vendor offers a robust process for identifying and capturing eligible services.

Frequently Asked Questions

What Is Internal Medicine Billing?

Internal medicine billing is the process of coding and submitting claims for services provided by internists. These services primarily include office evaluation and management visits, chronic disease management, preventive care, and care coordination.

Internal medicine billing differs from general primary care billing because of its emphasis on E/M coding, its Medicare-heavy payer mix, and the volume of potentially billable chronic care management services.

How Much Do Internal Medicine Billing Services Cost?

Medical billing services typically charge a percentage of monthly collections. Published rates in this market range from approximately 4% to 8%, with smaller practices sometimes paying a higher percentage.

Before comparing quotes, confirm whether credentialing, legacy A/R recovery, patient statements, denial management, and reporting are included.

What Is the Most Common Denial Reason in Internal Medicine?

Improper use of modifier 25 on same-day E/M services and procedures or preventive services is a significant denial risk.

Payers review these claims closely because modifier 25 can be misapplied. However, under-leveling E/M services can also cost practices substantial revenue even when claims are not denied.

Can a Billing Company Bill Chronic Care Management for Our Practice?

Yes. A billing company can help identify eligible CCM services, manage billing workflows, submit claims, and track related revenue.

The practice remains responsible for meeting applicable clinical, consent, documentation, and time-tracking requirements. The billing company handles the agreed billing and tracking responsibilities, while the clinical work and supporting documentation remain the practice’s responsibility.

Ask prospective vendors to explain exactly how these responsibilities are divided.

How Long Does It Take to Switch Medical Billing Companies?

Published transition timelines commonly range from four to six weeks.

The duration is important, but the transition process matters more. Ask whether the new billing company offers a parallel run, during which the new workflow is tested alongside the existing process before the final cutover.

A documented transition should also address outstanding claims, legacy A/R, payer access, reporting, and responsibility for claims submitted before the changeover.

Should a Solo Internist Outsource Medical Billing?

Outsourcing can be cost-effective for a solo practice that cannot justify the salary and benefits of a full-time biller.

It may also reduce dependence on a single employee. However, a solo practice with an experienced, reliable in-house biller and consistently healthy collections may benefit from retaining direct control over billing.

The right decision depends on cost, expertise, collections performance, and the practice’s operational needs.

What Should an Internal Medicine Practice’s Days in A/R Be?

Track days in accounts receivable monthly and compare the results against your practice’s own historical trend.

Also monitor the proportion of A/R older than 90 days. If more than approximately 20% of receivables are past 90 days, investigate whether claim follow-up, denials, payer processing, or other workflow issues are affecting collections.

How Do I Know If My Current Billing Company Is Underperforming?

Watch for these four warning signs:

1. Days in A/R are increasing over consecutive months.
2. More than 20% of A/R is older than 90 days.
3. Denials are not being reported or explained consistently.
4. You do not receive scheduled reports broken down by provider and payer.

If you need an independent assessment, consider requesting a free A/R analysis. RKR Prime offers a review based on your aging report and three months of denial data, with a written summary provided within three business days.

Sources

Company descriptions are based on information published by the respective providers.

Medical billing company sources

• Medical Billers and Coders — Outsourced medical billing for small practices.
• MediBill RCM — Internal medicine billing service providers.
• Precision Practice Management — Internal medicine billing and revenue cycle management.
• Outsource Strategies International — Internal medicine billing and coding.
• Medisys Data Solutions — Internal medicine billing for small practices.
• AnnexMed — Medical billing companies for small practices.
• CureMD — Revenue cycle management services.

Regulatory and coding sources

• Centers for Medicare & Medicaid Services (CMS) — ICD-10 code files.
• CMS — CY 2027 Medicare Physician Fee Schedule proposed rule fact sheet.
• Tebra — FY 2027 ICD-10-CM diagnosis code updates.
• Holland & Knight — CMS issues CY 2027 Medicare Physician Fee Schedule proposed rule.

CPT and HCPCS codes cited in this article should be verified against the current code books before use. Code sets are updated annually.

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