Every year at this time we get a version of the same call. A practice manager has spent August on the ICD-10-CM update, the coders have their crosswalk, the EHR vendor has confirmed the diagnosis table will load on September 30, and everyone feels ready. Then in the second week of October a run of CO-97 and CO-151 denials arrives on procedures that paid fine in September. Nobody changed anything on those claims. The payer did, because the NCCI quarterly update took effect the same day as the diagnosis codes and nobody loaded it.
The NCCI quarterly update for October 1, 2026 was posted by CMS on September 1, and the October 2026 HCPCS Level II file followed on September 10. The FY 2027 ICD-10-CM codes take effect the same day. So does the fourth-quarter Average Sales Price file that sets Medicare Part B drug payment. Four separate changes, one effective date. This article is the checklist we use to load all of them in the right order, with the reports we run on October 2 to confirm the loads worked.
A glossary line for the physicians reading. NCCI is the National Correct Coding Initiative, the Medicare program that publishes two kinds of edits: procedure-to-procedure (PTP) edits, which say which code pairs normally do not pay together on the same day, and Medically Unlikely Edits (MUEs), which cap how many units of a code will pay for one patient on one date. HCPCS Level II is the alphanumeric code set (G codes, J codes, Q codes and so on) that covers drugs, supplies and services CPT does not describe.
Key takeaways
- Four Medicare files change on October 1, 2026: ICD-10-CM, NCCI PTP and MUE edits, HCPCS Level II and the quarterly ASP drug pricing file.
- The NCCI files were posted September 1 and the HCPCS file September 10, so there is time to load and test both before the first October claim run.
- Claim scrubbers do not update themselves in every system; someone has to confirm the edit version in the software and the clearinghouse.
- Commercial payers and state Medicaid programs run their own edit tables and their own schedules, so the Medicare load is the start, not the finish.
- Run a same-day claims report on October 2 for bundled and unit denials to catch a failed load in the first week rather than the first remittance cycle.
What changes on October 1 and where it comes from
| File | Posted | Effective | What it affects | Who loads it |
|---|---|---|---|---|
| ICD-10-CM FY 2027 (190 new codes) | June 2026 | October 1, 2026 | Diagnosis coding on every claim with a date of service on or after October 1 | EHR and practice management vendors; coders update favorites and templates |
| NCCI PTP edits, practitioner version | September 1, 2026 | October 1, 2026 | Which code pairs bundle; modifier indicators | Claim scrubber vendor, clearinghouse, encoder |
| NCCI MUE, practitioner version | September 1, 2026 | October 1, 2026 | Maximum units per code per date of service | Claim scrubber vendor, charge master owner |
| HCPCS Level II October 2026 file | September 10, 2026 | October 1, 2026 | New, revised and discontinued J, Q, G and other alphanumeric codes | Charge master owner; drug and supply billing |
| Part B ASP drug pricing, Q4 2026 | September 2026 | October 1, 2026 | Medicare payment limits for drugs billed with J and Q codes | Fee schedule owner; expected-payment tables |
CMS implements NCCI versions on January 1, April 1, July 1 and October 1 every year. The October version is the one that collides with the diagnosis update, which is why it gets missed. The HCPCS quarterly file usually appears a week or two later than the NCCI file, and the October file is often the largest of the four quarters because it carries new codes for drugs approved earlier in the year.
Loading the October 2026 NCCI quarterly update
The first question is who owns the edit table in your setup. In some practice management systems the scrubber updates automatically from the vendor on a schedule. In others the practice has to download and import the file. In a few, the clearinghouse runs the edits and the practice management system runs none. We have seen practices that assumed all three were happening and found that none were.
The check is simple: open the scrubber settings and find the NCCI version date. If it says July 1, 2026 on October 2, the load did not happen. Do the same at the clearinghouse. Then, for the ten code pairs your practice bills most often together, look up the October modifier indicator in the CMS PTP file and compare it with what the scrubber shows. Quarterly updates add pairs, delete pairs and occasionally change an indicator from 1 to 0, which means a pair that paid with a modifier in September will not pay in October regardless of the modifier.
The MUE table is the one physicians feel most directly. Each code carries a maximum unit value and an MUE adjudication indicator: 1 means the limit is applied per claim line, 2 means per date of service and is an absolute policy limit that cannot be appealed, and 3 means per date of service but based on clinical expectation, which can be appealed with documentation. When an MUE value drops in a quarterly update, a practice billing a drug or a supply in units above the new value will see CO-151 denials (payment adjusted because the information submitted does not support this many services) on every claim until someone notices. Injectable drugs, allergy testing units, and time-based therapy codes are the usual victims.
Loading the HCPCS file
The October HCPCS file has three sections that matter to a physician office: new codes, discontinued codes and revised descriptors. New J codes appear for drugs that have been billed under an unclassified code such as J3490 or J3590 since approval. When a permanent code is assigned, most payers stop paying the unclassified code within a quarter or two, so the charge master needs the new code, its unit definition and the NDC crosswalk on October 1. Discontinued codes need an end date in the charge master so nobody can pick them after September 30.
Unit definitions are where the money goes wrong. A new J code might be defined as "per 1 mg" where the old unclassified billing used "per vial". A practice that keeps the old unit habit will bill one unit of a per-milligram code for a 100 mg dose and be paid for one milligram. This is a real and recurring source of revenue leakage in specialties that infuse or inject, and it is entirely preventable with a unit check on every new code.
The ASP file sets the Medicare payment limit for each drug code for the quarter. If your expected-payment table is not updated, your underpayment report will flag every drug claim in October as a variance, and the team will stop trusting the report. Load the ASP file the same day as the HCPCS file.
What commercial payers and Medicaid do
Medicare's files are the baseline. Most commercial payers license the NCCI edits or something close to them, but they apply them on their own schedules and add their own bundling rules on top. Several large payers publish a quarterly "reimbursement policy update" bulletin in September for October changes, and those bulletins are where you find edits that Medicare does not have. State Medicaid programs use a separate Medicaid NCCI edit set, which CMS also publishes, and it differs from the Medicare set in places.
The practical consequence is that a claim can pass your scrubber, which runs Medicare edits, and still be denied by a commercial payer running a stricter table. We do not think most independent practices should try to replicate every payer's edit table in the scrubber. We do think they should read the September bulletins from their top five payers and add the two or three edits that will hit their own code mix.
The October 2 report
The fastest way to find a failed load is not to wait for the remittance. On October 2, and again on October 9, run a report of every claim with an October date of service that the scrubber held or the clearinghouse rejected, grouped by edit reason. A spike in bundling holds on a pair that never used to hold means the new PTP file loaded and the coders need the new modifier indicator. No change at all on a practice that bills common bundled pairs means the file probably did not load.
Then, when the first October remittances arrive in the third week of the month, run the denial report for CO-97, CO-4, CO-151 and CO-16 with remark codes related to unit or code validity, and compare the counts with September. In our experience a practice that has loaded everything correctly sees a small rise in the first two weeks and a return to baseline by the end of the month. A practice that missed a file sees a rise that does not stop.
The mistakes we see every October
Treating the ICD-10 update as the whole job. Loading the edit files in the practice management system but not at the clearinghouse, or the reverse. Adding new J codes to the charge master without checking the unit definition. Leaving discontinued HCPCS codes active so the front desk keeps picking them for supplies. Letting the encoder subscription lapse so coders look up October pairs in a July table. None of these are dramatic. All of them produce four to eight weeks of denials that look like payer behavior and are actually a missed load.
The other mistake is assuming the vendor did it. Vendors are usually reliable about ICD-10 because clients scream when it fails. They are less reliable about NCCI and HCPCS because the failure is quieter. Ask for written confirmation of the load date for each file, and check it yourself.
Questions we hear
We are a primary care practice with no procedures. Does any of this apply to us?
Less of it, but not none. Primary care bills vaccines and their administration codes, injections such as 96372, screening codes with frequency limits, and the occasional joint injection or skin procedure. Each of those has PTP pairs and MUE values. The vaccine codes in particular change in the fall, and the flu vaccine administration pairs are a common October denial.
Can we appeal an MUE denial?
It depends on the adjudication indicator. An indicator of 2 is a hard policy limit and no appeal will succeed. An indicator of 1 or 3 can be appealed with documentation that supports the units billed, and for indicator 1 the fix is often to bill the units on separate lines with an appropriate modifier. Check the indicator before writing the appeal.
How long does the full load take?
For a single-specialty practice with one practice management system and one clearinghouse, a day of focused work by one person who knows the systems, plus an hour on October 2 for the report. For a multi-specialty group with a large charge master, plan for a week and assign the drug codes to someone who understands units.
What to do this week
- Confirm in writing with your practice management vendor, your clearinghouse and your encoder vendor the date each will load the October 1 NCCI and HCPCS files.
- Download the October PTP and MUE files from CMS and check the modifier indicator and MUE value for your twenty most common codes against what your scrubber shows.
- Read the October HCPCS file for new J and Q codes in your specialty; add them to the charge master with the correct unit definition and end-date any discontinued codes.
- Load the fourth-quarter ASP pricing file into your expected-payment table.
- Read the September reimbursement policy bulletins from your five largest commercial payers and note any October edit that will hit your code mix.
- Schedule the October 2 and October 9 held-claims reports now, with a named owner.
