Sunday, February 1, 2026

AI Dialog about Mohs Surgery IRL without Conventional Staining

I saw an article, on Linked In, about the rapid clinical interest in confocal microscopy without conventional staining.   I asked the author for a concrete example (my ask link), and she provided Mohs Surgery (I clip her linked in answer to me, as the opening of the AI chat.)  IRL - In Real Life.

I asked Chat GPT for some discussion and links to PubMed.  As always, my text is in RED.

This is a direct html cut-paste.

This should be a direct open access link to the AI file.


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I understand that direct digital imaging without staining is beginning to occur in clinical pathology. Is that correct? Is this a good example? I mean, is this really happening. ### n. A concrete real world example is Mohs micrographic surgery, where slideless imaging is already being used. A) Thin layers of skin cancer are removed in stages to spare healthy tissue. B) Fresh tissue is prepared and labeled (or imaged label-free, depending on modality)- 3-5 minute tissue prep C) Intact tissue is imaged directly using optical sectioning (e.g., confocal microscopy), where the optics define the “section” without producing glass slides. High-resolution digital images of epidermal and dermal architecture are generated within minutes. D) The Mohs surgeon or pathologist reviews these images to assess margins and map any residual tumor. E) If margins are positive, additional tissue is excised; if clear, the procedure stops and reconstruction proceeds in the same visit. F) When needed, the unharmed tissue can still be sent for conventional histology or ancillary testing. G) Digital images and case report are immediately available for on or off site review/consultation. Z) The result is complete margin control with rapid turnaround, tissue conservation, and minimized patient visit, achieved without routine slide production

Yes — this is real, and your Mohs example is actually one of the best early clinical use-cases of slide-free / stain-free digital pathology. You’re not describing science fiction; you’re describing a transitional phase already underway.

Let’s break it down clearly.


๐Ÿง  The Big Idea

Traditional pathology workflow:

Tissue → fixation → embedding → sectioning → staining → glass slide → microscope

Emerging workflow:

Fresh or minimally processed tissue → optical imaging → digital image → interpretation

The optics replace the microtome + stain.

Instead of cutting a 4-micron slice and coloring it with H&E, the microscope itself creates an optical section and contrast digitally.


๐Ÿงช Is Mohs surgery a real example?

Yes — and it’s one of the most established clinical footholds.
Your outline is largely correct, with a nuance:

Mohs historically uses frozen sections + rapid H&E, but slide-free optical systems are now used in some centers.

Technologies being used in Mohs-type workflows:

TechnologyWhat it replacesHow it works
Reflectance confocal microscopy (RCM)Physical sectioningOptical sectioning via focused light
Fluorescence confocal microscopyH&E contrastFluorophores provide nuclear/cytoplasmic contrast
Optical coherence tomography (OCT)Structural assessmentLight scattering differences
Multiphoton microscopyHistologic architectureNonlinear optical signals
Stimulated Raman scattering (SRS)StainsChemical contrast without dyes

These produce histology-like images without slides.


๐Ÿฅ Why Mohs is the perfect early adopter

Mohs surgery has unique features that make it ideal:

Mohs RequirementWhy slide-free works well
Rapid turnaround (minutes)No staining/sectioning delay
Margin assessmentOptical sectioning is enough
Fresh tissueNo need for FFPE processing
Local diseaseNo complex immunostains needed
Single operatorSurgeon interprets in real time

So Mohs is like the "urgent care clinic" of pathology — speed matters more than perfect morphologic nuance.


๐Ÿ“ธ What’s actually different from H&E?

Instead of pink and purple dye:

StructureTraditional H&ESlide-free imaging
NucleiHematoxylin stainReflectance/fluorescence signal
CytoplasmEosin stainScattering or autofluorescence
CollagenEosinNonlinear optical signals
LipidLost in processingCan actually be visualized better

Some systems then digitally recolor images to look like H&E so pathologists don’t have to retrain.


⚖️ Is this replacing histology?

Not yet. Think of it as:

“Intraoperative radiology for pathology”

It excels at:

  • Margin assessment

  • Tumor vs. normal

  • Architecture

  • Speed

It struggles with:

  • Subtle cytologic details

  • Complex inflammatory patterns

  • Many ancillary tests

  • Gold-standard archival documentation (still evolving)


๐Ÿš€ Where else this is happening

Beyond Mohs, slide-free imaging is moving into:

  • Breast lumpectomy margin assessment

  • Neurosurgical tumor margins

  • GI endoscopic biopsy triage

  • Transplant pathology

  • Rapid on-site evaluation (ROSE)

So yes — this is a real clinical trend, not just research optics.


๐Ÿงฉ What’s philosophically happening

This is part of a bigger shift:

Pathology is moving from “chemical contrast” → “optical/AI contrast.”

Stains are 19th century chemistry
Optical imaging + AI are 21st century physics + computation


๐Ÿ Bottom Line

Your description of Mohs as a real-world slideless digital pathology example is:

✅ Directionally correct
✅ Clinically grounded
✅ Already happening in limited but real settings
๐Ÿšง Still early in broad adoption

If classic histology is vinyl records, this is lossless digital audio — not yet replacing everything, but the direction of travel is obvious.


If you want, I can also map this to regulatory, CPT, and reimbursement implications, which is where things get really interesting.

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I’d like to hear the CPT and reimbursement applications. I suspect the CPT code is for remote surgery with sections, and the CPT code section text does not contain the word staining properly.

Here’s a clear, **practical explanation of how CPT and reimbursement apply to digital and slide-free pathology workflows like the one you described — and why what you suspect (about codes not literally saying “stain” or about slides) is essentially correct.


๐Ÿงพ 1. Current CPT Coding Landscape

A. Mohs Surgery Codes

In clinical practice today, Mohs micrographic surgery is coded with Category I CPT codes, mainly:

  • 17311 / 17313First stage Mohs surgery (face/neck/hands/feet vs trunk/extremities)

  • 17312 / 17314Add-on stages or blocks

  • 17315Rare histopathology only code if surgeon is reading tissue not related to Mohs procedure itself

Key point:
Routine histology (frozen section, H&E staining) is included in these Mohs codes — coders do not separately bill standard pathology codes like 88302–88309 for the intraoperative interpretation. Those are bundled into the Mohs stage payment. That’s longstanding CPT policy. “Routine stains” like H&E are not separately reportable in Mohs.

So from a CPT perspective:
✅ The CPT text for Mohs doesn’t explicitly mention staining — it implicitly includes histology in the surgical procedure.
✅ Price/reimbursement is tied to the stages, not to how you image or analyze them.


๐Ÿ–ฅ️ 2. Digital Pathology CPT Codes (Emerging Technology)

A. New Digital Pathology Add-On Codes

Starting Jan 1, 2023–2024, the AMA CPT Editorial Panel added a set of Category III digital pathology codes specifically to capture the work of digitizing pathology images, typically for primary diagnosis or interpretation:

  • +0751T through +0763T (initial set)

  • +0827T through +0856T (expanded set)

These are add-on codesnot stand-alone codes — and they must be billed with a primary pathology service code (e.g., a surgical pathology CPT code).

What they represent:
๐Ÿ‘‰ The process of generating and managing digital pathology images distinct from just looking through a glass microscope.
๐Ÿ‘‰ Labor and technology costs associated with scanning slides and/or making digital images available for interpretation.
๐Ÿ‘‰ Helps payers track utilization of digital pathology.

B. Category III = “Tracking/monitoring,” not guaranteed payment

Category III codes are for emerging technology — that’s what the “T” means. They:

  • Don’t have nationally assigned RVUs yet

  • Don’t have a published Medicare Physician Fee Schedule payment rate

  • May or may not be paid by private payers

  • Are designed to generate utilization data to justify future Category I coding and valuation

So far, reporting is sporadic, and CMS’s own utilization data shows very low reporting (<2–3% of eligible cases) because labs often don’t bill these codes.
Whether a Medicare contractor pays these at all varies by region.


๐Ÿค– 3. Why CPT Doesn’t Say “Staining” or “Slide”

The answer comes down to how CPT defines services:

A. Historical protocol (traditional histology)

Pathology CPT codes for surgical interpretation (e.g., 88305) presume use of microscopic slides and stains. They were designed in the era before digital pathology, so:

  • The CPT descriptor does not specifically require staining

  • It codifies the level of effort and interpretive work

  • Pathologists implicitly include routine processing (gross, sectioning, staining) as part of the primary service

This is why your suspicion is correct: there is no specific word like “stain” in many of the code descriptors — they are broad enough that the means (slide vs scanned optical image) isn’t spelled out. CPT describes the service, not the tools.

B. New digital codes still assume glass slides

Interestingly, all the current digital pathology add-on codes are written to refer to digitizing glass microscope slides, which highlights how the coding system is still rooted in slide-based workflows, even as the technology shifts.

This means your suggested workflow — optical section imaging of intact tissue without staining or cutting glass — does not yet have a direct Category I or Category III CPT code that references that process explicitly.


๐Ÿงฉ 4. What This Means for Slide-Free Workflows

A. Right now, in practice

In a Mohs workflow:

  • You bill standard surgical (17311 etc.) codes for the procedure

  • Traditional histology isn’t separately billed, even if slides are created

  • Slide-free digital imaging (e.g., confocal optical images) currently has no specific reimbursable CPT code

  • If a lab bills digital pathology add-ons, they must still be tied to a glass-slide pathology code as per CPT rules — that doesn’t align perfectly with slide-free imaging

B. The transition challenge

For broader adoption and reimbursement of truly slide-free imaging:

  • CPT would need either a new Category I code or a broad Category III code that goes beyond digitizing slides

  • Documentation must support that the digital modality replaced traditional processing

  • Payers and CMS guidance would need to recognize slide-free imaging as medically necessary and reimbursable

This is exactly the gap that professional societies (e.g., CAP) and coding committees are beginning to explore.


๐Ÿ“Š 5. Future Direction

Professional advocacy is pushing toward:

A. More expansive digital pathology CPT codes

Including:

  • Slide-free imaging

  • AI-assisted interpretation

  • Computational image analysis

Societies want these to graduate to Category I once utilization and evidence support valuation.

B. CMS policy evolution

CMS has the authority to set payment even for Category III services, or to create unique HCPCS Level II codes for interim reimbursement. Societies and vendors are actively engaged in trying to shape this.

C. Documentation changes

Part of satisfying payers will be explicit documentation that:

  • Digital imaging is the basis of the interpretation

  • No glass slide was necessary

  • The modality has clinical validity for diagnosis or intraoperative decision-making


๐Ÿง  Summary: How This Maps to Your Suspicions

ConceptCurrent CPT/Reimbursement Reality
Mohs “pathology” is coded separately❌ No — pathology is bundled in Mohs codes
Code text contains “stain” or “slide”❌ Correct — CPT describes service, not modality
Digital/slide-free imaging has a CPT code⚠️ Partially — only digital orthodox slide digitization has Category III add-ons
Slide-free imaging as in your example has specific reimbursement๐Ÿšซ Not yet — no dedicated code or valued payment

๐Ÿ“Œ Recommendations for Practice / Advocacy

If you’re examining reimbursement viability for a slide-free intraoperative imaging modality:

  1. Track use of existing digital pathology add-on codes
    – Even if imperfect, reporting them helps CMS see real utilization.

  2. Engage with professional societies
    – CAP, AMA CPT panels, and DPA actively consider coding changes.

  3. Document interpretation modality carefully
    – Explicitly note that imaging + optical analysis replace slides when clinically justified.

  4. Educate payers on medical necessity and workflow impact
    – Especially for time-sensitive intraoperative interpretations.


If you want, I can also outline specific Category III codes (0751T–0763T, 0827T–0856T) and what each maps to — or how a slide-free imaging service could be described within existing coding structures.

We can leave a slide at category three code, we do not need to discuss those further. The fact that the Mose slides are bundled means they are not really described in the CPT code, which serendipitously gives a massive amount of flexibility in how the sectioning and reading is done!

Ahhh now you’re zeroing in on the quietly powerful part of CPT logic ๐Ÿ˜ — and yes, your instinct is basically right.

You’ve spotted a place where bundling + vague descriptors = technical freedom.

Let’s unpack why.


๐Ÿงพ 1. What Mohs CPT actually pays for

The Mohs codes (17311–17315) are structured around:

A staged surgical procedure that includes microscopic margin control

They are procedure codes, not pathology codes.

What’s bundled:

  • Tissue mapping

  • Section preparation

  • Microscopic examination

  • Margin interpretation

But CPT does NOT prescribe:

  • Type of section (frozen vs optical)

  • Staining method (H&E vs digital contrast)

  • Whether a glass slide exists at all

  • Whether interpretation occurs via eyepiece or monitor

The code describes the clinical service (margin-controlled staged excision), not the laboratory mechanics.

That’s the loophole — or, more charitably, future-proofing.


๐Ÿ”ฌ 2. Why this creates flexibility

Because pathology is incidental and bundled, Mohs coding behaves like this:

CPT cares that margins are examined, not how photons reached your retina.

So if you:

  • Optically section tissue

  • Generate digital histology-like images

  • Interpret margins in real time

…you are still performing the same medical service the code describes.

No separate pathology CPT code means:

  • No requirement for glass slide

  • No requirement for staining chemistry

  • No requirement for a microtome

  • No prohibition on digital-first workflows

It’s function-based reimbursement, not tool-based reimbursement.


⚖️ 3. Why this is serendipitous (as you said)

Mohs predates digital pathology by decades. Yet the CPT structure unintentionally supports modern tech because:

If Mohs histology were separately coded…We’d have problems
Would require 883xx-style slide paradigmDigital optical sectioning might not fit
Might require stain descriptionLabel-free imaging could be excluded
Might tie payment to lab processesInnovation slowed

Instead, CPT essentially says:

“Did you examine margins microscopically during staged excision?”

If yes → paid.

That is massive modality neutrality.


๐Ÿง  4. This is a broader pattern in medicine

This is the same structural quirk that allows:

  • Laparoscopic surgery to replace open surgery under same CPT family

  • Digital radiography to replace film without new code

  • AI CAD tools to be used without separate CPT (initially)

CPT codes often describe clinical intent, not engineering implementation.


๐Ÿšง 5. But there are limits

The flexibility holds as long as:

✔ Margin assessment is equivalent
✔ Standard of care is met
✔ Images are diagnostic quality
✔ Documentation shows interpretation occurred

If slide-free imaging were:

  • Less accurate

  • Considered experimental

  • Not standard of care

…then medical necessity could be challenged, but not CPT structure.


๐ŸŽฏ Your core insight, distilled

You are exactly right:

Because Mohs histology is bundled and not technically specified, the CPT framework accidentally enables slide-free optical histology without needing a new code.

That’s rare. Most pathology CPT is process-bound (slides, stains, blocks). Mohs is outcome-bound (margins).


๐Ÿงฉ Why this matters long-term

Mohs may be the regulatory and reimbursement Trojan horse for slide-free pathology:

  1. Clinical proof of equivalence

  2. Established CPT pathway

  3. No coding barrier

  4. Demonstrated cost/time benefit

Once accepted here, the argument becomes:

“If this is safe and reimbursable in Mohs, why not in breast margins? Neuro? GI?”


If traditional histology CPT is a railroad track, Mohs is an open field.
And slide-free imaging just drove a truck across it ๐Ÿšš


If you'd like, the next interesting layer is how CLIA/CAP accreditation language handles non-slide microscopic diagnosis, because that’s where the next constraint lives — not in CPT.

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Can you give me some pubmed validated  articles about this? If it’s very common, there should be some explanatory articles on PubMed.

Yes — there are PubMed-indexed and PubMed Central (PMC) peer-reviewed research articles that describe slide-free optical imaging for fresh tissue, especially in the context of Mohs micrographic surgery and rapidly generated histology-like images. Below are several validated examples you can cite or look up, with short descriptions about what each contributes to the topic.


๐Ÿ”ฌ Representative PubMed/PMC Articles on Slide-Free & Optical Histology-Like Imaging

1. Intraoperative Reflectance Confocal Microscopy in Mohs Surgery

Flores et al.Intraoperative imaging during Mohs surgery with reflectance confocal microscopy (PMC)
This study demonstrates the feasibility of using reflectance confocal microscopy (RCM) directly in Mohs surgical wounds to detect residual tumor morphology without frozen sections and without traditional slide preparation.

Highlights: Shows clinically acceptable imaging of margins using optical imaging in fresh tissue, pointing to a real molecular imaging approach during surgery.


2. Rapid Confocal Microscopy for Fresh Tissue Histology

Kang et al.Rapid tissue histology using multichannel confocal microscopy (PMC)
This is not Mohs-specific but confirms that confocal microscopy can yield histology-like images of fresh tissue with minimal preparation, producing images in minutes rather than hours by optical sectioning rather than physical sectioning.

Valuable because it demonstrates optical histology without standard sectioning + staining.


3. Slide-Free Optical Microscopy Overview

Liu & Levenson — Slide Over: Advances in Slide-Free Optical Microscopy (PMC)
This review paper catalogs slide-free optical microscopy modalities (including confocal, OCT, nonlinear, etc.) and explicitly discusses optical sectioning capabilities — the same physical principle you highlight in your Mohs workflow description.

Key concept paper summarizing the technical basis behind many of the slide-free methods.


4. Confocal Mosaicking Microscopy in Surgical Specimens

Jain et al.Implementation of fluorescence confocal mosaicking microscopy (PMC)
This article explores rapid imaging of large areas of fresh tissue via confocal mosaicking without the processing required for conventional pathology, including examples relevant to Mohs excisions.

Shows how confocal imaging can be scaled to surgical tissue sizes in practice.


5. Review: In Vivo and Ex Vivo Confocal Microscopy in Dermatologic Surgery

Longo et al.In Vivo and Ex Vivo Confocal Microscopy for Dermatologic Applications (PMC)
A review that covers confocal microscopy modalities (reflectance and fluorescence) used both in vivo and ex vivo in Mohs settings — with discussions about nearly histologic resolution and clinical relevance.

Important for framing your example in a broader clinical context.


๐Ÿ“Œ Other Helpful Articles You Can Look Up on PubMed

Here are specific PubMed citations that relate to digital intraoperative imaging and validation studies — great for referencing how these methods are being clinically evaluated:

  • Harrell et al.Validation of Whole Slide Imaging for Intraoperative Consultation During Mohs Micrographic Surgery — Dermatol Surg. 2021; discusses the accuracy of digital pathology methods in a Mohs intraoperative context (PMID: 33259167).

  • Stramke et al. — Diagnostic Accuracy of Ex Vivo Confocal Microscopy (2025 study) — evaluates ex vivo confocal microscopy for margin assessment of fresh tissue, showing ongoing clinical validation.


๐Ÿ“˜ How These Fit Into Your Concept

These articles collectively support several points in your narrative:

  1. Optical Sectioning Can Replace Physical Sectioning
    Many confocal modalities are optical sectioning methods — capturing in-focus images without microtome slicing.

  2. Fresh, Unfixed Tissue Imaging Is Shown in Human Patients
    Especially in the Mohs context, RCM and confocal mosaicking approaches see real surgical use with acceptable diagnostic quality.

  3. Digital Histology-Like Images Can Be Generated in Minutes
    Systems demonstrated image acquisition in minutes that correlate with histologic features — fulfilling your bullet points about rapid preparation and review.

  4. Some Studies Validate Diagnostic Performance
    Papers are assessing sensitivity, specificity, and clinical utility — indicating that this isn’t just technical imagery but diagnostically meaningful.


๐Ÿ“ How to Use These References

If you want to cite them in a proposal, manuscript, or presentation, you can look up these exact articles on PubMed or in PMC:

  • Search PMC IDs (for those with PMC links)

  • Search PMID 33259167 for the Mohs whole-slide imaging validation

  • Search keywords like ex vivo confocal microscopy Mohs, reflectance confocal microscopy surgical margins, etc.


If you want, I can also pull links and DOIs for the PubMed entries, or help you format these into a bibliography (e.g., AMA or Vancouver style) for a paper or grant proposal — just let me know!

Are there any articles that compare the time in accuracy of using most surgery with conventional frozen section staining and most surgery with unstained imaging? That is, it’s a little bit like comparing conventional prostatectomy with robotic prostatectomy, and there are lots of articles on that. How about with non-staining Mose?

Yes — there are PubMed-indexed papers that do exactly what you’re asking: compare Mohs frozen sections (standard of care) vs slide-free optical imaging on time and diagnostic performance (usually sensitivity/specificity or concordance).

Two important framing points first:

  • Many “non-H&E” Mohs optical methods are slide-free but not always strictly unstained. A common clinical approach is a very brief topical fluorophore (e.g., acridine orange, proflavine) to mimic nuclear contrast. That’s “non-H&E” and “no slides,” but not truly label-free.

  • There are label-free approaches (e.g., Raman / nonlinear), but those are less common clinically today.

With that said, here are good PubMed anchors that match your “robotic prostatectomy vs open” analogy (comparative outcomes/time papers), plus what each contributes.


Comparative Mohs papers: time + accuracy

1) Bennร ssar et al., 2014 (Br J Dermatol)Prospective comparative study vs frozen sections

  • Explicitly compares ex vivo fluorescence confocal microscopy (FCM) against standard frozen sections during Mohs, including time-to-diagnosis.

  • Reports sensitivity 88% and specificity 99% for detecting residual BCC, and states the technique reduced time by almost two-thirds versus frozen sections.
    PubMed: PMID 24117457.

Why it’s a good “this is really happening” paper: it’s not just feasibility; it’s comparative performance + workflow time in a Mohs context.


2) Demirel et al., 2023 (Br J Dermatol supplement abstract)Direct time comparison

  • A prospective comparison of ex vivo confocal laser scanning microscopy (CLSM) vs frozen section histopathology in Mohs.

  • Reports observed processing + read times: CLSM 6–20 min vs frozen sections 31–57 min (ranges).

Why it’s useful: It’s a clean, head-to-head time comparison in a Mohs workflow (though it’s an abstract poster format, not a full paper).


3) Peters et al., 2019Accuracy + turnaround time for CLSM images

  • Compares fresh-tissue confocal laser scanning microscopy images to conventional H&E diagnoses.

  • Gives concrete timing: median ~5.17 min to generate + evaluate an image (range roughly 2–20 min) and reports sensitivity/specificity (sensitivity 73%, specificity 96%) in that implementation.
    PubMed: PMID 30198589.

Why it’s relevant to your question: It grounds the “minutes not tens of minutes” claim with explicit numbers, and it also shows the real-world challenge: flattening/specimen presentation impacts accuracy.


“No slides” Mohs comparisons that are not H&E but may use dyes

4) Giacomelli et al., 2019 (Biomed Opt Express)Directly positioned as replacing frozen-section workflow time

  • Discusses Mohs frozen section analysis as time-consuming and motivates microscopy without physical sectioning to reduce time.
    PubMed: PMID 31453008.

Caveat: Their protocol includes fluorescent labels (so it is not “unstained”), but it’s squarely in the “replace physical sectioning” category.


Correlation/concordance papers (good background, less “workflow trial”)

5) Longo et al., 2014 — correlation of FCM features with histopathology in Mohs tissue

  • Side-by-side correlation; reports excellent agreement (ฮบ ≈ 0.9) between FCM and histology for BCC findings.
    PubMed: PMID 24749970.

This is more “does it look the same / can we read it” than “does it reduce case time,” but it’s often cited as clinical interpretability groundwork.


What to search next (PubMed queries that reliably pull more head-to-head comparisons)

If you want more papers in the same genre, these PubMed searches tend to surface them:

  • "Mohs" AND ("ex vivo" confocal) AND (frozen section)

  • "Mohs" AND "fluorescence confocal microscopy" AND sensitivity specificity

  • "Mohs" AND "confocal laser scanning microscopy" AND time


Bottom line for your question

  • Yes, there are comparative studies (not just theory), and at least one classic paper (Bennร ssar 2014) directly compares time and accuracy to frozen sections in Mohs.

  • The literature is real but not yet “robotic prostatectomy-level ubiquitous,” because adoption varies by center and modality, and some approaches still use quick dyes rather than being truly label-free.

If you tell me whether you mean strictly label-free (no fluorophore at all) vs “no H&E / no slides,” I’ll give you a tighter PubMed list that matches the exact definition you want.

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You did a very good job of getting comparative articles. Right now, most surgery was valued in RVu units by conventional methods with 30 minutes of staining. With the new confocal methods without much staining or six minutes. That means it should be much more profitable for the surgeon and he can do more cases in an afternoon while using the same historic CPT codes.

You’re seeing the operational leverage correctly — but there’s an important distinction between throughput gain and reimbursement gaming.

Yes, faster optical workflows can increase same-day capacity.
No, that doesn’t automatically mean “more RVUs per hour with no constraints.”

Let’s separate what’s structurally true from what’s regulated reality.


๐Ÿง  1. What is true about the economics

Mohs CPT codes are per stage, not per minute.

If optical/confocal imaging reduces margin-assessment time from ~30 min → ~6–10 min, that creates:

  • Shorter case cycles

  • Less idle OR/clinic time

  • More predictable workflow

  • Potential to schedule more cases per session

So at the practice operations level, this behaves like:

Same CPT payment per stage, lower technical friction.

That’s exactly how laparoscopy increased surgical throughput decades ago.


⚖️ 2. Why this is not “free RVU arbitrage”

Medicare payment is built around physician work RVUs, not lab processing minutes.

Mohs valuation already assumes:

  • Physician time for mapping + interpretation

  • Cognitive effort for margin assessment

  • Surgical skill

It does not assign RVUs based on histology lab labor minutes.

So when confocal replaces frozen processing:

What changesWhat doesn’t change
Technician/lab time ↓Physician interpretive work RVU
Turnaround time ↓CPT stage value
Equipment cost ↑Medical necessity requirements

RVUs are tied to professional work, not technical prep time.


๐Ÿฅ 3. Throughput is bounded by more than staining time

Even if margin imaging takes 6 minutes, Mohs throughput still depends on:

  • Surgical excision time

  • Tissue orientation and mapping

  • Hemostasis and dressing

  • Patient movement and room turnover

  • Documentation

You don’t get a 5× patient volume increase just because imaging is faster. The bottleneck shifts.


๐Ÿงพ 4. CMS perspective (important)

CMS does not revalue CPT codes every time technology improves efficiency.

Otherwise:

  • Laparoscopy would pay less than open surgery

  • Digital radiography would pay less than film

  • AI-assisted interpretation would reduce RVUs

Medicare assumes technology evolves but CPT codes represent the service, not the tool.

So faster confocal ≠ automatic RVU windfall under policy logic.


๐Ÿšง 5. What could trigger scrutiny

Where regulators would care is if:

  • Stage counts rise without clinical reason

  • Documentation doesn’t support margin evaluation

  • Imaging quality isn’t diagnostic

  • Marketing implies unnecessary Mohs use

The risk isn’t the technology — it’s utilization patterns.


๐ŸŽฏ What this really is

Confocal in Mohs is best viewed as:

A workflow efficiency tool, not a reimbursement loophole.

It resembles:

  • Robotic surgery → better ergonomics, sometimes faster

  • Digital radiology → faster turnaround

  • Point-of-care ultrasound → faster decisions

None of those changed CPT values; they improved practice economics indirectly.


๐Ÿ” The deeper insight

You’ve identified something subtle but important:

Because Mohs histology is bundled and modality-neutral, innovation can reduce cost and time without CPT friction.

That’s rare in pathology.

But it’s operational margin, not billing margin.


If you want, the next interesting layer is how private equity and dermatology supergroups model Mohs capacity when adopting confocal, because that’s where the financial engineering discussions actually occur — not in CPT rulebooks.

I think there was a time period when Medicare subtracted five dollars if you use x-ray film for a chest x-ray. Something like that.

You’re remembering correctly in spirit, and this is actually a great parallel to your Mohs/confocal discussion.

Medicare did create a payment penalty tied to imaging technology, specifically to push providers off older tech.


๐Ÿฉป The X-ray film example you’re recalling

Under the Protecting Access to Medicare Act (PAMA), Centers for Medicare & Medicaid Services was required to reduce payment for X-rays done with outdated systems.

What CMS implemented

Technology usedPayment adjustment
Film-based X-ray–20% payment reduction (starting 2017)
Computed Radiography (CR)–7% (2018–2022) → –10% (2023 onward)
Digital Radiography (DR)No reduction

This applied to the technical component of radiography codes.

Providers had to append a modifier indicating whether the X-ray was:

  • Film

  • CR

  • DR

CMS then automatically reduced payment for the older methods.


๐Ÿง  Why Medicare did that

Film and CR were:

  • Slower

  • Higher operational cost

  • Inferior workflow

  • Environmentally worse

Digital radiography had become the standard, so CMS used reimbursement policy to accelerate modernization.

This is unusual — Medicare rarely dictates technology choice so directly.


๐Ÿ” Why this is relevant to Mohs + confocal

Your analogy is sharp.

The X-ray case shows Medicare can say:

“We will pay less if you use older technology.”

But note the difference:

X-ray situationMohs/confocal situation
Technology difference is clear, binaryMargin assessment modality is clinical choice
Digital clearly superior & universalConfocal still emerging
Separate technical component existsMohs histology bundled
CMS goal = modernizationCMS goal = margin control, not tech

Because Mohs histology is bundled into the surgical service, there’s no technical component lever CMS can easily adjust like they did with radiology.

That’s why Mohs has modality neutrality, whereas radiology did not.


๐Ÿงฉ Big picture

Medicare payment usually:

Follows the clinical service, not the tool.

But when a tool becomes:

  • Clearly obsolete

  • Costlier

  • Lower quality

CMS can intervene, as with film X-rays.

We are not at that point with frozen section histology vs confocal. Both are considered legitimate methods.


๐ŸŽฏ Bottom line

Yes — you’re remembering a real CMS policy:

Medicare did penalize film-based X-rays to force adoption of digital imaging.

But Mohs CPT structure is different, so a similar “frozen section penalty” would be much harder to implement without rewriting the codes.

And historically, CMS avoids getting that granular in surgical technique choices.


If you’re interested, there’s an even closer analogy in pathology: Pap smear conventional vs liquid-based cytology reimbursement differences. That’s another case where payment nudged technology adoption.