HCPCS code Q4158 – Kerecis Omega3 fish-skin graft

Key takeaways

HCPCS code Q4158 covers Kerecis Omega3 fish-skin graft, billed per square centimeter as an add-on to a 15271-15278 application code.

Choose the application code by wound site and total wound area, since 15275-15278 cover the feet, hands, face and scalp.

Bill one unit per square centimeter applied, round up to a whole number, and record the raw measurement in the chart.

Since January 1, 2026, Medicare pays Q4158 at a flat $127.14 per sq cm as an incident-to supply.

Novitas L35041 and First Coast L36377 cover diabetic foot ulcers and venous leg ulcers after standard care fails.

HCPCS code Q4158 is an add-on code for Kerecis Omega3

HCPCS code Q4158 is the supply code CMS assigns to Kerecis Omega3, a fish-skin graft billed per square centimeter. It never stands alone on a claim.

Instead, it rides on a skin substitute application code from the 15271-15278 range, and Medicare pays a flat rate for each unit in 2026.

Here are the core billing facts to confirm before you build the claim.

Kerecis Omega3 is a fish-skin graft for chronic ulcers

Kerecis Omega3 is an acellular matrix made from Atlantic cod skin. Both the HCPCS Level II descriptor and Kerecis’s own reimbursement documents map the product to Q4158.

It’s classed as a bioengineered skin and soft tissue substitute, so the same billing article A54117 governs it as other advanced wound care products.

Under the two LCDs this guide follows, coverage applies to diabetic foot ulcers and venous leg ulcers that haven’t responded to standard wound care. Sizing matters too. Kerecis sheets come in several sizes, and your units must reflect the graft area applied rather than the sheet you opened.

Every Q4158 line needs a 15271-15278 partner code

Q4158 is an add-on code, so it needs a primary application code from the 15271-15278 series on the same claim and date of service. Send it alone and expect a CO-B15 or CO-97 denial.

Two details pick the partner code: where the wound is and how large the total wound area is. According to the AMA CPT code set, 15271-15274 cover the trunk, arms and legs. Meanwhile, 15275-15278 cover the face, scalp, hands, feet and similar sites.

Within each site group, the split falls at 100 sq cm, as the grid below shows.

Treating several wounds on one date of service? Report a primary code for each wound location. Payers differ on whether Q4158 units go on one combined line or on separate lines per wound. Confirm the approach with the MAC or commercial plan first.

Units follow the graft area, always rounded up

Each unit of Q4158 is one square centimeter, and a fraction rounds up to the next whole number. So a 6.3 sq cm wound bills as seven units, not six. Billing the decimal instead is a common mismatch between the chart and the claim, and it triggers edits.

Work through the count in this order:

1. Measure the wound’s length and width in centimeters with a calibrated ruler or a digital wound-measurement tool.
2. Multiply length by width. For an irregular wound, use the longest dimension and the widest perpendicular dimension.
3. Round the result up to the next whole number.
4. Enter that number as the Q4158 unit quantity on the claim.
5. Record the raw measurement in the clinical note, so anyone can reconcile it with the billed units.

Here’s how that plays out. A patient has a diabetic foot ulcer on the heel that measures 3.0 cm by 2.1 cm. That’s 6.3 sq cm, so the claim carries 15275 with one unit and Q4158 with seven. At the 2026 Medicare rate, those seven units pay $889.98 for the graft, and the application code pays separately.

With several wounds, measure each one on its own and then add the areas together. Some payers want separate claim lines per wound instead, so check their policy before you combine units.

Medicare pays a flat $127.14 per sq cm in 2026

Medicare fee-for-service covers Q4158 when a patient meets the criteria in your MAC’s skin substitute policy. Novitas uses LCD L35041 with billing article A54117. First Coast uses LCD L36377 with article A57680. Criteria vary between contractors, so confirm the active LCD for your jurisdiction before you bill.

New skin substitute LCDs for diabetic foot ulcers and venous leg ulcers were due on January 1, 2026. These were L39756, L39760, L39764, L39806, L39828 and L39865. However, CMS withdrew them on December 24, 2025, before they took effect, so the existing MAC policies stayed in place.

Payment changed too. Since January 1, 2026, Medicare has paid Q4158 at a flat national rate of $127.14 per square centimeter. The CY2026 Physician Fee Schedule and OPPS final rules reclassified most skin substitutes, Q4158 included, as incident-to supplies. That flat rate replaces the older Average Sales Price (ASP) and MAC-priced methods, and Kerecis’s reimbursement materials list the same figure.

According to the CMS HCPCS overview, Q-codes are temporary codes that CMS updates every quarter. For that reason, check the current rate in the CMS Physician Fee Schedule lookup tool for the service year. Published rate tables can miss mid-year changes.

Place of service still shapes the primary code’s payment. Facility rates apply in a hospital outpatient department or ambulatory surgical center (ASC), while non-facility rates apply in a physician office. Because 15271-15278 pay differently in each setting, confirm the place-of-service code before you submit.

Coverage hinges on the wound type and failed standard care

Medicare covers Q4158 only when the encounter meets the medical necessity conditions in your MAC’s LCD. Under Novitas L35041 and First Coast L36377, that means documenting each patient against specific clinical thresholds before the graft goes on.

The core criteria typically include:

• A qualifying wound type: a diabetic foot ulcer or a venous leg ulcer
• At least four weeks without healing under standard wound care
• Documented failure of prior conservative treatment, such as standard dressings, compression or offloading
• Wound measurements in centimeters in the clinical note at each visit
• A physician order for the specific product
• The product lot number or label kept in the medical record

LCD criteria differ by MAC jurisdiction and can change between annual coding cycles. So check the current version of your MAC’s LCD before treating a patient with this product. Auditors regularly flag claims built on last year’s criteria.

Diagnosis codes have to match a DFU or VLU

Every Q4158 claim needs an ICD-10-CM diagnosis code that supports medical necessity, and it must match the wound type in the chart. The table below lists the main categories that support Q4158 under L35041 and L36377.

Pressure injuries and traumatic wounds fall outside the scope of L35041 and L36377. If a payer covers Kerecis Omega3 for those wounds, its own policy decides the rules. In every case, check that the billed code appears on your MAC’s covered diagnosis list. A plausible but unlisted code is a common denial trigger.

Prior authorization depends on who’s paying

Original Medicare needs no formal prior authorization (PA) for Q4158, but most other payers vary widely and change often. The table shows general patterns only. Eligibility checks confirm coverage, yet PA for the specific product still needs its own confirmation.

Commercial coverage is less uniform than Medicare’s. UnitedHealthcare has a commercial skin and soft tissue substitute policy that likely includes Q4158. Similarly, BCBS plans, Aetna and Cigna keep category-level policies for advanced wound care, and terms vary by local plan.

Before you apply the product under any commercial plan, get answers to three questions:

• Does Q4158 appear on the plan’s covered HCPCS list?
• Is PA required, and what documentation must go with the request?
• Does the plan cap applications per wound episode?

Log the PA number, approval date and authorized units in the record. That trail protects the practice during audits and appeals.

Q4158 and A2019 are two different Kerecis codes

Q4158 and A2019 both describe Kerecis fish-skin products, but not the same one. Q4158 is the Q-code for Kerecis Omega3, while A2019 is the A-code for Kerecis Omega3 MariGen Shield. Both bill per square centimeter as add-on codes.

Q4178 sometimes shows up as a Kerecis code in error. Its descriptor is Floweramniopatch, an amniotic membrane product from another manufacturer. Since CMS can add, revise or retire codes each quarter, check the current HCPCS Level II file. The AAPC HCPCS code lookup also shows each code’s current descriptor.

The practical rule is simple: read the label on the package you opened. If it names Kerecis Omega3 MariGen Shield, bill A2019. A standard Kerecis Omega3 wound graft label maps to Q4158. Never assign a code from the product family name alone.

Seven denial triggers and the fix for each

Q4158 claims stack three risks on one line: an add-on rule, a unit count and LCD medical necessity. That’s why they fail more often than most supply codes. Knowing the common denial codes behind these rejections helps billers fix them faster and stop repeats.

Several of these start in the chart, long before anyone opens the claim form. That’s where the next section picks up.

The chart has to prove the wound, the product and the math

Documentation decides whether a Q4158 claim survives an audit. A reviewer who has never met the patient should be able to confirm the wound type, size, product and treatment history from the chart alone. A clean claim for this code starts with complete notes at the time of service.

Record these elements at every Q4158 encounter:

• Wound measurement: length and width in centimeters, in the procedure note for that date of service
• Wound photographs: pre-application photos, which support both clinical and audit review
• Treatment history: prior conservative care, how long the wound has gone without healing, and why standard treatment failed
• Physician order: a signed order naming the Kerecis Omega3 product and application instructions
• Product label or lot number: kept in the chart to confirm identity and traceability
• Procedure note: the application technique, wound preparation and total graft area applied
• Diagnosis codes: ICD-10-CM codes tied to the documented wound type and listed in the LCD

Build this capture into the clinical visit rather than leaving it for billing. Teams that photograph wounds each visit and log measurements in structured fields already have the audit trail. When a remittance does come back short, its reason code shows which element was missing.

Run this checklist before a Q4158 claim goes out

A Q4158 claim moves from the bedside note to charge entry, then through a scrub, submission and remittance. Most errors slip in at charge entry, so pause there and confirm each item below.

• The product label says Kerecis Omega3, not MariGen Shield.
• The primary code matches the wound site and total area, from 15271 to 15278.
• Q4158 units equal the applied area, rounded up to a whole number.
• The diagnosis is a DFU or VLU code on your MAC’s covered list.
• The chart shows four weeks of failed standard care.
• Measurements, photos, the physician order and the lot number are in the record.
• For non-Medicare payers, the PA number and authorized units are on file.
• The place-of-service code reflects where the graft was applied.

Once every box is ticked, the claim is ready to send. Doing this at charge entry takes a minute, whereas an appeal can take weeks.

How claims management software keeps Q4158 claims moving

Many wound care teams still build a Q4158 claim by hand. Someone copies the application code, units and diagnosis from the chart into a claim form. Then they chase the authorization number by email. Each copy step is another chance to drop a unit or miss a field.

Practice management software like Pabau removes the retyping. Its claims software for practices pre-fills the CMS-1500 from the patient record, so the visit’s codes land on the claim. Built-in CPT, HCPCS and ICD-10 lookup libraries help coders confirm Q4158 and its partner code. And the claim won’t send until required fields, like the authorization number, are complete.

US practices submit through Claim.MD, which adds real-time eligibility checks before the visit. After submission, your team can track each claim’s status and post remittances as payments land. That way, a denial shows up the day it posts, while the notes are still fresh.

Send cleaner wound care claims

Pabau pre-fills wound care claims from the patient record and checks required fields before they send. Then it tracks each claim through to payment.

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Conclusion

Q4158 pays well when three details line up. You need the right partner code for the site and a unit count the chart can prove. The diagnosis also has to be a DFU or VLU code the LCD accepts. Get those right at the point of care, and the claim rarely needs a second pass.

The trade-off is time at the bedside. Measuring, photographing and logging the lot number add a few minutes to each visit. Still, those minutes cost far less than appealing a denied graft worth hundreds of dollars.

To see how practice management software like Pabau pre-fills and tracks wound care claims from the patient record, book a demo with our team.

Continue your research

Seeing Q4178 on a Kerecis claim? HCPCS code Q4178 covers Floweramniopatch, the amniotic product behind that code.

Billing another skin substitute this week? HCPCS code Q4101 walks through Apligraf billing for chronic wounds.

Comparing 2026 payment across grafts? HCPCS code Q4124 explains Oasis Ultra billing under the new flat rate.

Want fewer denials across every code? Denial management in healthcare shows how to track, appeal and prevent claim rejections.

Checking coverage before the graft goes on? Insurance eligibility verification sets out what to confirm with each payer before the visit.

Frequently asked questions