October brings more than the start of a new quarter for healthcare practices. It also brings important Medicare billing and coding updates that can influence how claims are processed, edited, and reimbursed.
Several CMS updates took effect on October 1, 2026, including the new fiscal year ICD-10-CM diagnosis code set, the quarterly HCPCS Level II update, and a new version of the National Correct Coding Initiative (NCCI) edits. Medicare Administrative Contractors (MACs) began implementing the October update to the Physician Fee Schedule database shortly after, on October 5. While these updates may seem routine, even a small change in a coding rule or payment indicator can create unexpected problems when a practice continues billing the same way it did the month before.
What Changed This October?
CMS regularly updates the rules and systems that influence Medicare claim processing. This October, the changes fall into four areas.
1. The FY 2027 ICD-10-CM Code Set
The new diagnosis code set adds 190 codes, deletes 30, and revises 4. It applies to patient encounters from October 1, 2026, through September 30, 2027. For professional and outpatient claims, the date of service determines which code set applies: a visit on September 30 uses the old codes, and a visit on October 1 uses the new ones.
The additions are concentrated in a few specialties:
- Cardiology. Dilated cardiomyopathy (I42.0) now expands into I42.00 (unspecified), I42.01 (familial-genetic), and I42.09 (other). New codes also capture arrhythmogenic cardiomyopathy, catecholaminergic polymorphic ventricular tachycardia (CPVT), Brugada syndrome, and ventricular bigeminy.
- Oncology. New secondary malignancy codes identify specific metastatic sites, including C78.31 (larynx), C78.32 (pharynx), and C79.83 (oral cavity), which previously had to be reported with less specific “other” codes.
- OB/GYN and maternal-fetal medicine. New category O31.4 adds 33 codes for continuing pregnancy after vanishing twin syndrome, and ectopic pregnancy coding has been expanded.
- Podiatry and orthopedics. Plantar fasciitis now has its own subcategory (M67.A-) by foot and laterality, separate from plantar fascial fibromatosis. Osteomyelitis codes under M86.8X- also expand by site and laterality.
- ENT. New subcategory J34.83- identifies odontogenic sinusitis, with a sixth character for the sinus involved.
- Hematology. Qualitative platelet defects (D69.1) are split into D69.11 (Glanzmann thrombasthenia) and D69.19 (other qualitative platelet defects).
- Other notable additions. Post-bariatric hypoglycemia codes under E89.83, more granular adult BMI codes at the low end of the range (Z68.1-), and new codes for genetic conditions such as Lynch syndrome and Loeys-Dietz syndrome.
Deleted codes deserve particular attention. Among the 30 removed codes is the S23.420 series for sternoclavicular sprain. Any deleted code still sitting in an EHR favorites list, superbill, or charge template will produce a rejected claim for October dates of service.
2. NCCI Edits, Version 32.3
NCCI version 32.3 took effect October 1, 2026. It updates procedure-to-procedure (PTP) edits, Medically Unlikely Edits (MUEs), and add-on code edits for practitioner services, outpatient hospital services, and durable medical equipment. CMS posted the quarterly lists of added, deleted, and revised edit pairs on September 1.
A code pair that processed normally in September may now trigger a bundling edit, and a modifier indicator may have changed. The practical step is to compare the quarterly change files against the code combinations your practice bills most often.
3. The Quarterly HCPCS Level II Update
The October HCPCS update, posted August 18, adds 88 new codes, deletes 14, revises 11 long descriptors, and changes payment for 5. Highlights include:
- Wound care. New codes for wound dressing and skin substitute products, including A2046 and A2048.
- Prosthetics and orthotics. New codes L1330 (thoracic orthosis, sternal compression, off the shelf) and L1972 (ankle foot orthosis with ankle joint, off the shelf). L1971 is revised to describe a prefabricated device customized to fit a specific patient. L8696 is discontinued, and L8030 and L8031 are revised to cover any type of breast prosthesis, with or without adhesive.
- Drugs. Several J codes are added, discontinued, or revised.
- Laboratory. New proprietary laboratory analysis (PLA) codes take effect and are contractor-priced.
- Home health consolidated billing. CMS added 19 supply codes, including syringes, catheters, ostomy supplies, and wound care tape, to the home health non-routine supply list. When a patient is under a home health episode, these items are now billed through the home health agency rather than separately.
4. The Medicare Physician Fee Schedule Database
The October update to the Physician Fee Schedule database (Change Request 14588) includes new codes, procedure status changes, short descriptor revisions, and payment policy indicator changes. It also updates pricing for several skin substitute and wound care codes (A2046, A2047, A2049, Q4207, Q4223, and Q4243) for October 1 through December 31, 2026.
One detail matters for A/R: CMS directs MACs to adjust previously processed claims that providers bring to their attention. In other words, a claim paid under an outdated rate is not guaranteed to be corrected automatically. Someone has to notice the difference and request the adjustment.
Why These Changes Show Up as Denials
For billing teams, these aren’t simply technical changes to keep on file. They can directly affect claims already moving through the revenue cycle.
A service combination that processed normally in September may encounter a different edit in October. A modifier that was previously accepted may require another look. A diagnosis code that was valid last month may no longer exist. A frequently billed service may process differently than expected.
And sometimes, the first sign that something has changed is a denial.
The First Few Weeks Matter
The weeks immediately following a Medicare update are an important time to pay closer attention to claim activity.
An isolated rejection may be nothing unusual. But when the same code, service, modifier, or payer issue begins appearing repeatedly, it deserves attention.
That is where proactive revenue cycle management becomes valuable.
Instead of simply correcting and resubmitting each denied claim, practices should look for the reason behind the pattern. A new coding edit may be responsible. Documentation may no longer support the way a service is being billed. A system may need to be updated, or a billing workflow may still be following an older requirement.
Identifying the cause early can prevent the same issue from reaching dozens of additional claims.
An October Checklist
- Confirm your EHR and practice management system have loaded the FY 2027 ICD-10-CM code set, and remove deleted codes from pick lists, favorites, and templates.
- Review the NCCI version 32.3 change files against your most frequently billed code pairs.
- Check the HCPCS update for any new, deleted, or revised codes in your specialty, particularly wound care, orthotics, drugs, and laboratory services.
- For patients under a home health episode, confirm that supplies on the expanded consolidated billing list are routed to the home health agency.
- Compare October remittances against the updated fee schedule and request adjustments where payments don’t match.
- Track denial reasons by code for the first 30 to 60 days so patterns surface early.
Staying Current Helps Keep Revenue Moving
Healthcare billing never stays still for long. Coding requirements change, payer policies evolve, and Medicare updates continue throughout the year.
Practices don’t need to react to every change with a complete overhaul. They do, however, need a revenue cycle that notices when something is no longer working as expected.
Regularly reviewing claim rejections, denial patterns, payment differences, and coding changes can help practices catch issues before they become larger A/R problems.
At Navira Medical Billing, we believe strong revenue cycle management is not simply about getting claims submitted. It’s about staying aware of what’s changing, understanding how those changes affect reimbursement, and responding before small issues become recurring problems.
Because when billing rules change, your revenue cycle should be ready to change with them.
Sources
- CMS: ICD-10 Codes (FY 2027 update files)
- CMS: NCCI PTP Edits, Version 32.3 (Transmittal R13829CP)
- CMS: Medicare NCCI Procedure to Procedure Edits
- CMS: MPFSDB October 2026 Update (Transmittal R13929CP)
- CMS: HCPCS Codes Used for Home Health Consolidated Billing, October 2026 (MM14510)
- AAPC: CMS Finalizes October 2026 HCPCS Level II Changes
- AOPA: New HCPCS Codes and Code Changes for October 1, 2026
