What Changes on October 1 and January 1: A Documentation Checklist for Practice Leaders in 2026

Two federal changes land in the next four months. Neither is about care. Both decide whether care gets paid for, and one of them decides whether the patient still has coverage at all.

The first is the FY 2027 ICD-10-CM code set, effective for dates of service on or after October 1, 2026: 190 new codes, 30 deleted, four revised, no grace period. The second is CMS guidance letting states sort Medicaid recipients into three tiers when deciding who is too sick to meet a twenty-hour-a-week work or volunteer requirement. Most expansion states begin January 1.

Here is what to fix before each date.

October 1: the small update is the dangerous one

By raw count this is a lighter revision than recent years. That is the trap. A big update gets a project plan and a meeting series. A small one gets skipped, and the changes that did land sit in high-volume everyday coding rather than in the exotic corners nobody bills.

A sprain code that has sat on orthopedic superbills since the 2015 transition stops working. The whole family of codes for organic solvent poisoning is deleted. The code most outpatient practices use for the most common cause of heel pain is replaced by three codes that demand something the old one never did, which is a side.

Laterality is the part that costs money quietly. A code that never asked left or right now asks. The clinician who has documented that diagnosis the same way for eleven years will keep documenting it the same way, because nothing in the encounter tells her otherwise. The claim does not bounce because anyone made a mistake. It bounces because the note no longer contains a field the code requires.

Three mechanics worth putting on a whiteboard:

Outpatient coding follows date of service. Inpatient follows date of discharge. A late-September admission discharged in October codes under the new set.
ICD-10-CM binds every HIPAA-covered entity. Commercial payers, Medicaid managed care plans, and workers' compensation carriers all flip the same morning Medicare does.
There is no grace period. That sentence gets repeated every autumn and it is still true this autumn.

The October checklist

Run your own top 50Pull your top 50 diagnosis codes by volume for the last twelve months and run them against the FY 2027 deletions list. Your list, not the vendor's summary of it.
Fix the template, not the clinicianFor every deleted code whose replacement requires laterality, find the template, the smart phrase, or the order set that feeds it. Fix the template. Reminding clinicians is not a fix; it is a plan to be disappointed in November.
Ask your clearinghouse two questionsWhat is your go-live date, and do you hold or reject a retired code. Those two behaviors produce very different Octobers.
Set a denial-rate tripwireWatch the first two weeks of October. If nobody is watching the rate, you find out at day forty-five, which is thirty days of claims too late.

The Sarah Matt Briefing goes out Tuesday mornings with the operational read on changes like this one, well before the denial reports land. Subscribe here.

January 1: a tier is not a diagnosis

CMS guidance, released through a deck on medicaid.gov, lets states sort medical frailty exemptions into three tiers. Tier 1 exempts on diagnosis alone with no further paperwork; the examples given are end-stage renal disease, ALS, and end-stage cancer. Tier 2 may indicate frailty but requires supporting data, such as billing for recent acute care or particular pharmacy codes. Tier 3 goes to case-by-case review.

The example below is CMS's own, and it is the whole argument.

Vision loss from type 2 diabetes is tier 1. Type 2 diabetes managed on several medications, with possible peripheral neuropathy and no recent admissions, is tier 3. Same disease. Different tier.

The tier 3 patient is the ordinary internal medicine panel. I see her on charity care afternoons and nothing about her chart is dramatic. Four medications. Numbness she mentions in passing, at the end of the visit, while putting her coat on. No admissions, because the regimen is working. Under this structure, the fact that her care is working is what puts her in the review queue.

The dates and the numbers:

Twenty hours per week of work or volunteering.
Most expansion states start January 1. Iowa starts December 1. Nebraska, Montana, and Arkansas are already implementing, with no coverage-loss data released.
Self-attestation is permitted in year one. Documentation is required as of 2028. Two cliffs, not one.
A preliminary CBO estimate puts coverage losses above seven million over the coming years.
CMS faces a legal challenge from two dozen states.

The AMA called the approach data-driven and said it could reduce documentation burden on beneficiaries and physicians. That is a fair read of the mechanism. A state that can auto-exempt someone from claims data it already holds spares that person a form, and the tier 1 list does real work. Data-driven and correct are not the same claim, though, and disease groups are lobbying right now to move their patients up. Tier placement is going to be a negotiated outcome before it is a clinical one.

The January checklist

Find your tiersAsk which tier your highest-volume chronic conditions land in under your state's adopted structure. If your state has not published one, that is your answer for now and your question again in November.
Name who receives the requestsIdentify who receives the tier 3 documentation requests. It will not be the physician. It will be whoever answers the phone.
Count the hoursCase-by-case review across a panel of any size is a staffing line, not a task you assign to someone who already has one.
Decide the mid-treatment rule nowDecide what the practice does when a patient loses coverage mid-treatment. The answer improvised in February becomes policy by March, and nobody will ever revisit it.

What the two dates have in common

On the surface, nothing. One is a code set and one is a coverage rule, and they will be handled by different people in different meetings.

Underneath, both move a decision that used to live in the clinical note into a field on a form, and both put the consequence on the patient rather than on the person filling out the field.

The heel-pain code will get fixed, because a denial is loud and somebody gets a report about it. The tier 3 patient generates no report at all. She just stops coming.

Written for practice leaders and health system executives who have to turn a federal calendar into a staffing decision. The Briefing ships every Tuesday: subscribe here.

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