HCPCS code B4105: In-line cartridge digestive enzymes billing guide

Key Takeaways

HCPCS code B4105 describes an in-line cartridge containing digestive enzymes for enteral feeding, each unit billed separately under HCPCS Level II.

B4105 is covered under Medicare Part B as a DMEPOS enteral nutrition supply, governed by CMS Policy Article A58833 and applicable DME MAC LCD.

Billing requires a Standard Written Order (SWO) with all five required elements, treating-practitioner documentation of medical necessity in the medical record, and the KX modifier on the claim to confirm LCD coverage criteria are met — CMS eliminated the Certificate of Medical Necessity (CMN) for dates of service on or after January 1, 2023.

Pabau’s claims management software helps DME suppliers and healthcare practices track documentation, reduce denials, and streamline DMEPOS billing workflows.

HCPCS code B4105 describes one in-line cartridge containing digestive enzymes, used within an enteral feeding system and billed under HCPCS Level II. It’s a DMEPOS supply reimbursed through Medicare Part B, covered under CMS Policy Article A58833 and the applicable DME MAC’s Local Coverage Determination (LCD).

This guide covers the code’s definition, Medicare coverage rules, required documentation, the ICD-10 diagnosis codes that support a claim, and the step-by-step billing process, plus the current reimbursement rate and the most common denial reasons to avoid.

HCPCS code B4105: Definition and key attributes

HCPCS code B4105 covers the billing of one in-line cartridge containing digestive enzymes for use in an enteral feeding system. Getting the descriptor right, and matching it to the supply dispensed, is the starting point for clean billing.

The code belongs to HCPCS Level II, the code set maintained by the Centers for Medicare and Medicaid Services (CMS) for products, supplies, and services not captured by CPT. B4105 sits within the B4100-B4162 enteral formulas and additives range, a subset of the broader B-range covering enteral and parenteral therapy supplies.

The “each” unit designation matters for quantity reporting. Bill one unit per cartridge dispensed. Billing multiple units as a single line item without supporting documentation is a frequent audit flag.

Medicare coverage for B4105 under Part B

Medicare Part B covers enteral nutrition supplies, including HCPCS code B4105, under the prosthetic device benefit when a beneficiary cannot absorb sufficient nutrients through standard oral intake. Coverage is administered through the Durable Medical Equipment, Prosthetics, Orthotics, and Supplies (DMEPOS) benefit, not the outpatient physician benefit.

The governing policy document is CMS Policy Article A58833, which outlines covered codes and documentation standards for enteral nutrition.

Suppliers must reference this article alongside the applicable Local Coverage Determination (LCD) issued by their Durable Medical Equipment Medicare Administrative Contractor (DME MAC). Coverage details, including covered ICD-10 codes and documentation standards, can vary by DME MAC jurisdiction.

• Jurisdiction A: Noridian Healthcare Solutions
• Jurisdiction B: CGS Administrators
• Jurisdiction C: CGS Administrators
• Jurisdiction D: Noridian Healthcare Solutions

Verify the applicable LCD from your jurisdiction’s DME MAC before submitting B4105 claims. HIPAA-compliant documentation applies throughout the claims process, including how patient records are stored and transmitted to payers.

Coverage criteria and medical necessity for HCPCS code B4105

Medicare will not cover HCPCS code B4105 without documented medical necessity. Per CMS Policy Article A58833 and applicable LCD guidance, the following conditions — typically confirmed through a GI assessment and documented in the medical record — must be satisfied before a claim is submitted.

• The beneficiary must have a functioning gastrointestinal tract but be unable to maintain adequate nutrition through standard oral intake due to a medical condition.
• The treating practitioner must complete a Standard Written Order (SWO) specifying the item, and the clinical rationale for enteral nutrition therapy — formula type, administration method, and reason — must be documented in the beneficiary’s medical record.
• The in-line enzyme cartridge (B4105) must be medically indicated for the patient’s enteral feeding system, with the clinical need documented in the medical record and available to the DME MAC on request.
• The KX modifier must be appended to the claim line to attest that the LCD’s coverage criteria are met. If criteria are not met, the supplier must use modifier GA, GY, or GZ instead.
• National Correct Coding Initiative (NCCI) edits must be reviewed to confirm B4105 is not bundled with another supply code being billed on the same date of service.

Coverage is never automatic. Each of these criteria must be independently documented. Relying on a verbal order, or missing medical-record documentation of medical necessity, is the most common reason B4105 claims are returned. Tightening medical forms fixes this. Frame all coverage determinations as “per CMS policy article A58833 and applicable LCD” rather than treating coverage as guaranteed.

Covered ICD-10 diagnosis codes for B4105

The specific ICD-10-CM codes that support HCPCS code B4105 are determined by each DME MAC’s LCD, not by a single national list. The following codes appear frequently in coverage determinations for the GI and pancreatic malabsorption conditions that functional medicine practices manage. Verify against your MAC’s current LCD before billing.

This table isn’t exhaustive. CMS Policy Article A58833 lists additional Group 1 diagnosis codes for GI and pancreatic malabsorption, including K50.118, K50.818, K50.918, K51.818, K51.918, K86.0, E84.8, E84.9, Q45.3, Z90.410, Z90.411, and the diabetes-complication codes E08.69, E09.69, E10.69, E11.69, and E13.69.

Consult the MAC’s LCD and Policy Article A58833 for the complete Group 1 covered-diagnosis list before billing. Coding to the highest specificity reduces audit risk. Use the most specific code available rather than an unspecified combination code.

Documentation requirements for billing B4105

Incomplete documentation is the leading cause of B4105 claim denials. CGS Medicare’s enteral nutrition correct coding guidance, which applies to DME MAC Jurisdictions B and C, specifies a checklist of records that must be on file before a claim is submitted. Other MAC jurisdictions follow substantially the same requirements under their LCDs.

Use digital forms to reduce manual errors and ensure nothing is missing before claim submission — a GI review of systems template helps capture the clinical detail a reviewer expects. The required elements are:

• Standard Written Order (SWO): Effective January 1, 2020, CMS retired the five-element order, seven-element order, and detailed written order and replaced them with a single Standard Written Order. The SWO must include the beneficiary’s name or Medicare Beneficiary Identifier (MBI), the order date, a general description of the item, the quantity, and the treating practitioner’s name or NPI plus signature. It must reach the supplier before the claim is submitted.
• Medical-record documentation of medical necessity: CMS eliminated the Certificate of Medical Necessity (CMN) and DME Information Form (DIF) for dates of service on or after January 1, 2023 (CMS Special Edition article SE22002). No CMN or DIF is submitted with, or required for, current claims. Instead, the treating practitioner’s own clinical documentation — progress notes, evaluations, or a signed statement — must support medical necessity and be kept in the patient’s medical record, available to the DME MAC on request.
• Supporting medical records: Progress notes, hospital discharge summaries, or specialist reports that document why the patient cannot maintain adequate oral nutrition. Records should reference the specific condition driving the need for enzyme supplementation.
• KX modifier: Append the KX modifier to the claim line to attest that the treating practitioner’s documentation confirms the LCD’s coverage criteria are met. Without it (or GA/GY/GZ where criteria aren’t met), expect a denial.
• Supplier records: Delivery documentation confirming the item was received by the beneficiary, including the quantity delivered and date of delivery.

Protecting patient data during billing is a parallel obligation. The SWO and all medical records containing protected health information must be stored and transmitted in compliance with HIPAA’s Security Rule. Claims management software can centralize this documentation and flag incomplete files before submission.

How to bill HCPCS code B4105: Step-by-step

HCPCS code B4105 is billed by DMEPOS suppliers, not physician offices, using the CMS-1500 claim form or its electronic equivalent (837P transaction). The claim routes to the beneficiary’s assigned DME MAC jurisdiction based on the patient’s zip code.

Before submitting, confirm the automated billing workflows in your practice management system are configured for DME claim routing.

1. Gather documentation. Confirm the SWO, medical-record documentation of medical necessity, and delivery records are complete and on file. No claim should be submitted until all documentation requirements are met.
2. Confirm ICD-10 linkage. Identify the primary ICD-10-CM diagnosis code from the MAC’s LCD covered-diagnosis list. The diagnosis must match the clinical rationale documented in the medical record and described on the SWO.
3. Complete the CMS-1500 claim line. DME suppliers bill on the CMS-1500 (or its 837P electronic equivalent), a professional claim — bill types and revenue codes are UB-04/837I institutional concepts and don’t apply here. Enter HCPCS code B4105 and any required modifier (including KX, to attest the LCD’s coverage criteria are met) in Box 24D, the quantity dispensed in Box 24G, and the ICD-10-CM diagnosis pointer in Box 24E, linking the line to the corresponding diagnosis code entered in Box 21.
4. Submit to the DME MAC. Route the claim electronically via the 837P transaction set to the MAC jurisdiction covering the beneficiary’s zip code. Retain acknowledgment of receipt.
5. Track the remittance advice. Review the ERA/EOB for denial codes. Common denial codes for enteral supply claims include CO-50 (not deemed medically necessary), CO-16 (claim lacks required information — check the accompanying remark code for the missing element), and CO-4 (the procedure code is inconsistent with the modifier used, or a required modifier is missing).

Using practice management software that integrates DME claim submission with your documentation workflow reduces manual re-keying errors and keeps audit trails clean.

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Pabau's claims management software helps DME suppliers and healthcare practices track documentation, automate follow-ups, and reduce enteral nutrition claim denials. See how it works in a live demo.

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Medicare reimbursement rate for HCPCS code B4105

HCPCS code B4105 is priced under the CMS DMEPOS fee schedule, which is updated annually and varies by geographic locality. Stating a fixed dollar figure here would be misleading because rates change each January 1 and differ across fee schedule areas.

To find the current allowable for B4105 in your locality, use the CMS DMEPOS fee schedule — B4105 is priced under the DMEPOS fee schedule, not the Physician Fee Schedule. Search by HCPCS code B4105 and select your state or pricing area, or use your DME MAC’s fee schedule lookup (Noridian or CGS) for jurisdiction-specific amounts.

• Medicare typically reimburses 80% of the fee schedule allowable after the Part B deductible is met. The beneficiary is responsible for the remaining 20% coinsurance.
• Competitive Bidding Program (CBP) areas may apply different payment rates for DMEPOS items. Confirm whether B4105 falls under a competitive bidding contract in your service area.
• Reimbursement amounts for enteral nutrition supplies may be subject to adjustments under CMS’s annual DMEPOS payment policy updates. Verify rates at the start of each calendar year.

Common B4105 billing errors and how to avoid them

Enteral nutrition claims, including HCPCS code B4105, carry a higher-than-average denial rate in DMEPOS audits. Most errors are preventable with a pre-submission checklist. The table below maps the most frequent denial scenarios to their corrective actions.

Practice management software that automates modifier checks and frequency tracking helps DME suppliers, and the primary care practices referring these patients, catch these errors before the claim leaves the building.

Related HCPCS codes in the enteral nutrition B range

Choosing the wrong B-range code is a straightforward error that triggers a corrected claim and delays payment. The table below maps the codes adjacent to HCPCS code B4105, helping billers distinguish the enzyme cartridge supply from enteral formulas and other delivery accessories.

B4105 is specifically for the in-line enzyme cartridge supply, not the formula itself. Billers frequently confuse accessory supply codes with formula codes. Each must be billed on a separate claim line. Pabau’s procedure code library covers related supply codes, including B4157, across the enteral and parenteral nutrition range.

2026 Code update: Is HCPCS code B4105 still active?

HCPCS Level II codes are updated annually by CMS, with changes taking effect on January 1 of each year. Codes can be added, revised, or deleted.

Based on available data from reference sources including hcpcsdata.com, HCPCS code B4105 appears to be active for 2026 with no description change noted. However, this cannot be confirmed without checking the official CMS HCPCS annual update file directly.

To verify the current status of any HCPCS code, including B4105, use the CGS Medicare coding resources or download the current-year HCPCS release file from CMS’s official HCPCS page. Check the “deleted codes” and “revised codes” tabs in the CMS update file before the start of every plan year.

Always treat the CMS official release file as the authoritative source. Third-party code databases (including this page) reflect available data but may not capture mid-year revisions or corrections issued by CMS between major updates.

Consult your HIPAA compliance obligations alongside code status verification as part of your annual billing readiness review.

Conclusion

HCPCS code B4105 is a narrowly defined supply code for in-line digestive enzyme cartridges used in enteral feeding systems.

Coverage hinges on three non-negotiable requirements: a qualifying diagnosis, a complete Standard Written Order (SWO) backed by medical-record documentation of medical necessity, and confirmation that the beneficiary meets the functional GI tract criteria under CMS Policy Article A58833 and the applicable MAC LCD.

CMS eliminated the Certificate of Medical Necessity (CMN) for dates of service on or after January 1, 2023 — the SWO, the medical record, and the KX modifier now carry that weight.

Pabau’s claims management software gives DME suppliers and healthcare billing teams a structured workflow for tracking documentation, flagging incomplete files before submission, and managing remittance data to reduce denial rates. To see how Pabau handles DMEPOS claim workflows, book a demo with the team.

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