Quick answer: A consultation requires a documented request from another provider, an opinion rendered, and a report sent back, while an established patient visit simply means the patient was seen by the same specialty group within the past three years. Billing the wrong one, especially for Medicare patients, is one of the most common and most preventable reasons infectious disease claims get denied.
What Separates a Consultation From an Established Visit
Coders sometimes treat consultation coding as a judgment call, but the decision should follow defined payer, documentation, and patient-history rules.
For commercial payers that still recognize consultation codes, the medical record should support three core elements:
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A request from a physician, qualified healthcare professional, or other appropriate source for the infectious disease specialist’s opinion or advice.
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The infectious disease specialist’s evaluation, opinion, and recommendations.
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Communication of the findings or recommendations back to the requesting provider when required by the payer’s policy.
An established-patient visit is determined differently. The key question is whether the patient received qualifying professional services from the same physician or qualified healthcare professional—or another clinician of the same specialty and subspecialty in the same group practice—within the previous three years. If so, the patient is generally established, regardless of who referred the patient, whether the current diagnosis is new, or whether a different ID clinician sees the patient this time.
For example, a patient who was treated by an infectious disease physician in the same group for cellulitis two years ago is generally an established patient when returning for an unrelated fungal infection. The new diagnosis and new referral do not reset the three-year patient-status rule.
Medicare has not recognized outpatient or inpatient consultation codes for Part B payment since January 1, 2010. Instead, physicians must report the E/M code that best reflects the setting, patient status, and level of service. For office and outpatient encounters, that generally means the appropriate new- or established-patient E/M code.
Some commercial payers still reimburse the remaining outpatient consultation codes, typically 99242–99245, subject to their own coverage and documentation policies. This creates a common source of infectious disease billing errors: one practice may need payer-specific workflows for a clinically similar referral encounter.
Why Denial Rates Keep Climbing
Denials are not a small, occasional annoyance anymore, they are a growing structural problem across medical billing, and infectious disease groups are not immune.
Here is what the data shows going into 2026:
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The industry wide initial denial rate reached 11.8 percent in 2024, up from 10.2 percent just a few years earlier, per the Experian Health State of Claims Report 2025.
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41 percent of providers now report that more than 10 percent of their claims are denied, up from 38 percent in 2024 and 30 percent in 2022, a rise every year the survey has run.
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Half of providers surveyed named missing or inaccurate claim data as the top denial driver, with authorization issues and registration errors close behind.
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Administrative cost per denied claim climbed from $43.84 in 2022 to $57.23 in 2023, so every denial is getting more expensive to fix, not just more frequent.
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An older but still widely cited OIG review found that 42 percent of evaluation and management claims in a single audit year were coded incorrectly, with 19 percent lacking adequate documentation altogether.
None of these numbers are specific to infectious disease alone, but the specialty's heavy reliance on referrals, hospital handoffs, and recurring follow up visits for chronic conditions puts it squarely in the path of these trends. Specialty groups looking to optimize their workflow amid these rising trends often benefit from partnering with experts in specialty medical billing services to plug workflow gaps.
The Coding Mistakes That Cause These Denials
Four patterns show up again and again in infectious disease billing audits.
Billing a consult code for a Medicare patient. This is close to an automatic denial. It usually happens when a coder defaults to whatever code was used for the last visit type rather than checking the payer first.
Miscounting new versus established. A patient treated for cellulitis two years ago who now returns for an unrelated fungal infection still counts as established if anyone in the same specialty and group saw them within three years. Coders who rely only on the referral letter, instead of checking the practice management system, get this wrong often.
Missing documentation for the three Rs. Even on payers that still accept consult codes, a claim can be denied if there is no written record of the referring provider's request or no report sent back confirming findings. A one line chart note rarely holds up under review.
Continuing to bill consult level visits after care shifts to active management. Once the infectious disease physician takes over ongoing treatment, for example managing a long course of IV antibiotics, later visits should be billed as established patient visits, not repeated consultations. Some practices keep billing at consult level through an entire treatment course, which is a pattern payers are trained to flag.
What This Costs a Practice
The financial exposure adds up faster than most practices expect.
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Reworking a single denied claim costs between $25 and $118 in biller labor depending on complexity, according to CAQH Index and MGMA data.
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Roughly 90 percent of denials require at least some human review before resubmission, which pulls staff time away from other billing work.
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Only about 35 percent of denied claims are ever appealed, meaning the remaining 65 percent are frequently written off entirely, quiet revenue loss that never shows up as a single dramatic event.
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Of the appeals that are filed, around 70 percent are eventually overturned, per Premier Inc. data, which suggests a large share of denied revenue was collectible all along, it just needed someone to fight for it.
For a practice running a high volume of referral based and hospital follow up visits, even a small percentage of misclassified consultation codes can translate into a steady, ongoing revenue leak.
How to Fix This
The corrections here are not complicated, they just have to be applied consistently, every time.
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Confirm the payer before choosing between a consultation code and an office visit code. Never default to what was billed last time.
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Check the patient's visit history in the practice system rather than trusting the referral letter to determine new versus established status.
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Build documentation prompts into visit templates so physicians record the referring provider's name, the reason for referral, and confirmation that a report was sent back.
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Run a small monthly audit, even ten charts per provider is enough to catch a bad pattern before it becomes routine.
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Train coders specifically on infectious disease referral patterns rather than relying on general E/M training alone, since this specialty's mix of hospital consults, chronic follow ups, and recurring visits does not map cleanly onto generic coding rules.
Practices that do not have the internal bandwidth for this often bring in a billing partner that already understands these referral patterns. QWay Healthcare works specifically with specialty practices, including infectious disease groups, through targeted infectious diseases billing and coding services to build payer-specific coding checks directly into the claims workflow, catching consult versus established errors before submission instead of after a denial letter arrives.
Frequently Asked Questions
Does Medicare pay for consultation codes at all?
No. Medicare eliminated payment for CPT consultation codes, 99241 through 99245, in 2010. Visits that would otherwise be billed as consultations must use new or established patient office visit codes for Medicare patients.
How do I determine if a patient is new or established?
Check whether any physician of the same specialty in the same practice group has treated the patient within the past three years. If so, they are established, even if the current visit is for a completely different condition.
Can a properly billed consultation still get denied?
Yes. Even on payers that accept consult codes, missing documentation of the request, the rendered opinion, or the report sent back to the referring provider is enough to trigger a denial.
What happens once the infectious disease physician starts managing the condition directly?
Once care shifts from giving advice to active ongoing management, later visits are generally billed as established patient visits rather than repeated consultations.
Is outsourcing this part of billing worth it for a smaller practice?
Often yes, particularly once denials tied to consult versus established coding become a recurring pattern rather than an occasional mistake. A specialty focused billing partner such as QWay Healthcare can catch these errors before claims go out rather than after they bounce back.
The Bottom line
The gap between a consultation and an established patient visit is not a minor technicality, it is one of the most common and most preventable reasons infectious disease claims get denied. Verifying the payer, checking patient history properly, and documenting the three Rs consistently will resolve most of these denials, and a specialty aware billing partner can close whatever gaps remain.