190 new ICD-10 codes went live on October 1. Here's what breaks first on your claims.

On October 1, 2026, the FY 2027 ICD-10-CM code set took effect. It brings 190 new diagnosis codes, 30 deleted codes and 4 revised codes. There is no grace period. Every claim with a date of service on or after October 1 has to use the new set.

When a code gets split into more specific sub-codes, the old code stops being billable the day the split happens. If your EHR still offers it, or a provider has it saved as a favorite, the claim goes out wrong. You usually find out two to four weeks later, as a denial.

Here are the changes we're watching for the practices we work with.

The changes that matter most

Plantar fasciitis

Plantar fasciitis has moved to its own subcategory: M67.A01 for the right foot, M67.A02 for the left and M67.A09 for unspecified. M72.2 is now only for plantar fascial fibromatosis (Ledderhose disease) and has its own sub-codes, so M72.2 on its own is no longer billable. Urgent care, family medicine and pain management clinics see plantar fasciitis every week, which makes this one of the easiest denials to pick up this month.

Adult BMI

The old adult BMI code Z68.1 has been split into Z68.18 (BMI 18.4 or less) and Z68.19 (BMI 18.5 to 19.9). If your clinic documents BMI for weight counseling or risk adjustment, make sure your templates pull the new codes.

Odontogenic sinusitis

Sinusitis that starts from a tooth now has its own codes in the J34.83- range (J34.830 through J34.839), split by sinus. Urgent care and family practices that treat sinus infections should know they exist, even if they won't use them often.

Pregnancy

OB/GYN gets the largest single group: a new O31.4- subcategory for a pregnancy that continues after vanishing twin syndrome, broken down by trimester and fetus.

Everything else

There is also a new category for pelvic abscesses (K6A) and new Z codes for exposures such as burn pits, Agent Orange and blast overpressure.

What to do this week

1. Confirm the new code set is live in your EHR and billing software. Most vendors pushed it already, but "downloaded" and "active" are not the same thing.
2. Clean up provider favorites and pick lists. This is where deleted codes keep coming back after everyone thinks they're gone.
3. Check claims dated October 1 onward before they go out, starting with the diagnosis codes.
4. Watch your first denials closely. An invalid-diagnosis denial is a quick fix in the first two weeks. It gets a lot harder once they pile up.
5. Tell your providers. A two-minute note at the morning huddle about plantar fasciitis and BMI will save more claims than any software update.

At TrueCycle RCM, every claim is checked against the current code set before it's submitted, so an outdated code gets fixed on our side instead of by your payer.

Source: CDC and CMS FY 2027 ICD-10-CM files (effective October 1, 2026).