HCPCS code Q4140 – Biodfence, per square centimeter

Key takeaways

HCPCS code Q4140 describes Biodfence, per square centimeter, a Level II Q-series code for a dehydrated amniotic membrane skin substitute billed by wound area

From January 1, 2026, CMS pays Q4140 as an incident-to supply at a single site-neutral rate rather than on ASP

The 2026 rate is roughly $127.28 per cm² under the physician fee schedule and $127.14 per cm² under the OPPS. Q4140 sits in APC 6002

No national LCD covers skin substitutes. Novitas, First Coast and CGS apply L35041 with article A54117, while other MACs decide case by case

Always pair Q4140 with a CPT application code from 15271 to 15278, and Pabau’s claims management software flags a missing one before submission

Biodfence product overview

Biodfence is a dehydrated amniotic membrane skin substitute designed for chronic wounds where the body’s own tissue repair is insufficient. It is regulated as a Section 361 human cell and tissue product. Confirm the current FDA pathway against the manufacturer label before billing. Applied as a sheet, it provides a temporary structural matrix to support wound closure.

Medicare coverage for these products centers on chronic venous leg ulcers and diabetic foot ulcers that have failed standard wound care. Wound care programs and dermatology practices both bill the product per square centimeter applied. Wound measurement at the time of application is both a clinical and a billing requirement.

Q4140 fee schedule and Medicare payment rates in 2026

Medicare no longer pays Q4140 on Average Selling Price. Since January 1, 2026, CMS treats skin substitute products as incident-to supplies when they are applied during a covered procedure. Payment runs through the physician fee schedule in the non-facility setting and through the OPPS in hospital outpatient departments.

The rate is site-neutral. CMS set roughly $127.28 per square centimeter under the physician fee schedule, which is geographically adjusted. The OPPS rate is $127.14 per square centimeter and is not geographically adjusted.

Payment now turns on wound measurement, because the units billed carry it in full. Confirm the current figures in the CY2026 fee schedule files before you bill, since CMS issues technical corrections.

Place of service still decides which system pays. A physician office bills Q4140 under the physician fee schedule. A hospital outpatient department bills under the OPPS. The two rates are close but not identical, and the wrong place-of-service code remains a frequent audit trigger.

Use the CMS Physician Fee Schedule lookup to verify current payment rates for Q4140 by MAC jurisdiction and place-of-service indicator before billing.

What replaced the high-cost and low-cost APC split

The high-cost and low-cost grouping is gone. CMS eliminated it in the CY2026 OPPS final rule and deleted codes C5271 through C5278 on December 31, 2025. Skin substitute products moved into three new APCs, 6000, 6001 and 6002, under the new status indicator S1.

Products are now grouped by FDA pathway rather than by cost, across the 361 HCT/P, 510(k) and PMA categories. Only biologics licensed under Section 351 of the PHS Act kept ASP methodology. Q4140 is a Section 361 HCT/P, so it does not qualify for that exception.

Sheet-form products such as Biodfence are unpackaged and separately paid under the OPPS. Q4140 therefore sits in APC 6002 rather than being swept into the payment for the application procedure. The comparison below sets the 2025 rules against the 2026 rules line by line.

Facility vs non-facility billing for Q4140

Place of service (POS) determines which fee schedule governs Q4140 reimbursement and which bill type codes apply. Getting it wrong invites an audit as well as a delayed payment.

Confirm bill type codes and revenue codes with your specific Medicare Administrative Contractor (MAC) before billing. Noridian, Novitas, CGS, and Palmetto GBA may have jurisdiction-specific guidance that supersedes general CMS tables.

CPT application codes to bill alongside Q4140

Q4140 is a product code. It cannot stand alone on a claim. According to CMS billing article 54117, the application of bioengineered skin substitutes requires a companion CPT application code from the 15271-15278 series. Submitting Q4140 without the correct application code is the single most common denial for this product.

Codes 15273, 15274, 15277 and 15278 are not pediatric codes. They apply to any patient whose total wound surface area reaches 100 sq cm or more. The 1% of body area wording in the descriptor is an alternate measure for infants and children, not an age restriction on the code.

ICD-10-CM diagnosis codes supported by Q4140

Covered diagnosis lists sit in the MAC’s local coverage policy, not in a single national list. Where LCD L35041 applies, its billing article A54117 carries the ICD-10-CM codes that support a skin substitute application. Billing Q4140 against a diagnosis outside that list creates an automatic denial. Check the patient’s diagnosis against the applicable covered list before the product is opened.

Always select the most specific ICD-10-CM code available. An unspecified code increases denial risk, because it does not clearly demonstrate the wound characteristics the coverage policy requires. Coverage under L35041 centers on lower extremity chronic non-healing wounds, so burn and pressure injury indications depend on the payer.

Coverage guidelines and the skin substitute LCDs

There is no national Local Coverage Determination for skin substitutes. The policy that carries the Q-code and covered diagnosis lists is LCD L35041, Application of Bioengineered Skin Substitutes to Lower Extremity Chronic Non-Healing Wounds. Its billing article is A54117.

L35041 and A54117 are active in the Novitas, First Coast and CGS jurisdictions only. Palmetto GBA, NGS, WPS and Noridian carry no skin substitute LCD and adjudicate these claims case by case. Check your own MAC’s position on skin substitutes before the product goes on the wound.

A harmonized set of DFU and VLU skin substitute LCDs was withdrawn on December 24, 2025, before it ever took effect. No single national coverage number replaced the jurisdictional patchwork, so document criteria against the policy that applies to you.

Where L35041 applies, covered indications generally include:

• Full-thickness or partial-thickness diabetic foot ulcers (DFUs) present for at least 30 days and unresponsive to standard wound care
• Venous leg ulcers that have failed conservative treatment (compression, wound dressings) for at least 30 days
• Lower extremity chronic non-healing wounds with serial measurements showing little or no progress
• Wounds where the record shows an adequate trial of standard care before the first application

Payer-specific coverage notes

Commercial payers such as BCBS and Aetna follow their own medical policies for bioengineered skin substitutes. Those policies may differ from L35041 on covered diagnoses, applications permitted per year, and prior authorization. Prior authorization for Q4140 is payer-specific. Some MACs and commercial plans require it and others do not. Check the payer’s current policy and your MAC’s jurisdiction guidance before each application episode.

Documentation requirements for Q4140 billing

Documentation is what carries a Q4140 claim through review. CMS, and L35041 where it applies, require specific elements in the medical record before and at the time of application.

• Wound measurements (cm²): Record the length and width of the wound surface in centimeters. This drives the Q4140 unit quantity billed
• Wound type and duration: Confirm the wound type (DFU, venous ulcer, surgical wound) and how long it has been present
• Prior treatment history: At least 30 days of standard wound care with documented failure to respond
• Physician order: A signed order for the skin substitute application specifying the product and indication
• Medical necessity narrative: A note from the treating clinician explaining why Biodfence is appropriate for this specific patient
• Product label and lot number: Document the product applied, including manufacturer and lot number, in the procedure note

Assemble the charge detail before the claim goes out. A complete package carries Q4140, the companion application code, and every supporting ICD-10-CM code.

CY2026 CMS updates affecting Q4140

The CY2026 rules rewrote skin substitute payment rather than adjusting it. Wound care practices need to reset expected reimbursement, and to recheck every fee estimate built on a 2025 assumption.

• Incident-to supply payment: From January 1, 2026, CMS pays skin substitute products as supplies furnished with a covered application procedure. That holds under both the PFS and the OPPS
• One site-neutral rate: Roughly $127.28 per square centimeter under the PFS, geographically adjusted, and $127.14 under the OPPS, where no geographic adjustment applies
• FDA pathway groups: Products now sit in three groups by FDA pathway, covering 361 HCT/P, 510(k) and PMA products, rather than in cost tiers
• A narrow ASP exception: Only biologics licensed under Section 351 of the PHS Act kept ASP methodology. Q4140 is a 361 HCT/P, so it does not qualify
• OPPS restructuring: CMS deleted C5271 through C5278 on December 31, 2025 and dropped the high-cost and low-cost grouping. New APCs 6000, 6001 and 6002 carry status indicator S1
• Sheet-form products stay separately paid: The OPPS packaging carve-out for non-sheet forms does not reach Biodfence. Q4140 lands in APC 6002
• Q-code status: Q4140 remains an active 2026 code for Biodfence, so confirm it against the current CMS HCPCS code files before billing
• Litigation did not delay it: A manufacturer challenge in the Northern District of Texas was dismissed on jurisdictional and exhaustion grounds. The policy took effect as scheduled

Related HCPCS skin substitute codes

Q4140 sits within a large family of skin substitute Q-codes. Coders often confuse adjacent codes when products share similar descriptions. Use the AAPC HCPCS code lookup to verify the current code assigned to the specific product applied.

Never substitute one Q-code for another to achieve a higher reimbursement rate. Each code is product-specific; billing Q4140 for a different product constitutes upcoding and creates false claims liability.

Common billing errors with Q4140

These are the patterns that generate the most denials and the most rework for wound care billing teams. Effective denial management in healthcare starts with preventing them before submission, rather than chasing them afterward.

• Missing companion application code: Submitting Q4140 without a 15271-15278 CPT code on the same claim. This is the top denial reason and it is entirely preventable
• Wrong place-of-service code: Billing POS 11 for a procedure performed in a hospital outpatient department pays under the wrong system. It may also constitute improper billing
• Insufficient wound measurement documentation: The units billed for Q4140 must equal the wound area in cm². Rounding up or estimating without a documented measurement creates an overpayment risk
• Off-label ICD-10-CM diagnosis code: Pairing Q4140 with a diagnosis outside your MAC covered list produces an automatic denial, and the appeal path is narrow
• Failing to document prior treatment failure: L35041 requires evidence of at least 30 days of standard wound care. Claims without it are non-covered
• Using a retired or incorrect Q-code: CMS updates Q-code assignments quarterly, and an outdated code for Biodfence produces a code-not-on-file rejection
• Quoting a retired ASP rate: Q4140 has not been paid on Average Selling Price since January 1, 2026. An ASP-based estimate will never match the remittance

How Pabau supports skin substitute billing workflows

Practices that apply skin substitutes regularly need a system that keeps wound measurements, companion codes, and documentation requirements connected. Under the 2026 per-square-centimeter rate, the measurement in the chart is the number that gets paid.

Practice management software like Pabau holds those elements in one patient record. Pabau’s claims management software tracks what a Q4140 claim needs, from the wound measurement through to submission. Tying the treatment note to the claim means companion codes stop getting missed.

The measurement, the signed order, and the product lot number all sit beside the charge, so nobody reconciles two systems at month end. See how Pabau’s billing tools fit your wound care workflow by booking a demo.

Streamline skin substitute billing with Pabau

Pabau’s claims management software tracks wound measurements, flags missing companion codes, and helps wound care practices submit cleaner claims with fewer denials.

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Conclusion

The 2026 rules moved the risk on a Q4140 claim from pricing to measurement. When every square centimeter pays the same fixed amount, the figure in the wound note becomes the figure on the remittance. Tightening measurement discipline pays back faster than any appeal you write.

Coverage deserves the same caution. Until CMS replaces the withdrawn DFU and VLU policies, your own MAC decides whether the application is covered at all. Confirm that position before the product is opened, not after the denial lands.

Get those two right and most of the rework this code generates disappears. Book a demo to see how Pabau keeps wound measurements, companion codes, and claim submission in one workflow.

Continue your research

Need to understand the full claims process before submitting Q4140? What is medical billing explains the end-to-end process from charge capture through remittance.

Getting denials on skin substitute claims? Denial management in healthcare covers root-cause analysis and appeal strategies for common remittance codes.

Want to understand how clearinghouses process wound care claims? Medical claims clearinghouse explains how electronic claims are validated, scrubbed, and routed to payers.

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