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ICD-10 changes October 2026: the FY2027 coder checklist

FY2027 ICD-10-CM applies to services from October 1, 2026. The codes that stop being billable, what replaces them, and what to update before claims go out.

ICDcodes.org editorial team · Published September 24, 2026 · Applies to ICD-10-CM FY2027 (October 1, 2026 – September 30, 2027)

Key points

  • The FY2027 ICD-10-CM code set applies to services furnished on or after October 1, 2026. Services before that date keep FY2026 codes, whenever the claim is billed.
  • 15 codes that were billable in FY2026 became headers and can no longer be submitted. Each must be replaced with one of its new child codes.
  • 15 billable codes were deleted outright, 190 codes were added and 4 descriptions were revised.
  • Update every pick list, superbill and template that stores diagnosis codes, then paste them into the batch checker before the first FY2027 claims go out.

This post is the action list. The complete record of every addition, deletion and revision is on the FY2027 changes page, and the reasons behind the October and April cycle are in the update cycle guide.

Which ICD-10-CM code set applies to a claim after October 1, 2026?

The date of service decides the code set, not the date the claim is coded or submitted. The HIPAA code-set rule in 45 CFR 162.1000 requires covered entities to use medical data code sets “valid at the time the health care is furnished.” The FY2027 Official Guidelines give their own period of use on the title page as October 1, 2026 to September 30, 2027.

A claim for an office visit on September 30, 2026 therefore uses FY2026 codes even if it is billed in November. A visit on October 1, 2026 uses FY2027 codes, even if it was scheduled and pre-coded in September. The regulation does not say how a single inpatient stay that runs across October 1 is handled. Follow the claims-processing instructions of the payer you bill.

Why does a subdivided code stop being billable on October 1?

A subdivided code stops being billable because it now has children, and the Official Guidelines treat a code that is not carried to its full length as invalid:

“A three-character code is to be used only if it is not further subdivided. A code is invalid if it has not been coded to the full number of characters required for that code, including the 7th character, if applicable.”
ICD-10-CM Official Guidelines for Coding and Reporting FY2027, Section I.B.2

The subdivided code stays in the classification as a header, so it still appears in every lookup and looks normal on a superbill. That makes a subdivision easier to miss than a deletion; the billable codes guide explains the difference between a header and a billable code.

Which codes stop being billable for FY2027, and what replaces them?

These 15 codes were billable in FY2026 and are headers in FY2027. On this site a header is shown with a trailing dash. Choose the child code the documentation supports; the unspecified child is correct only when the record gives no more detail (see the unspecified codes guide).

Now a headerDescriptionBill one of these instead
D69.1-Qualitative platelet defectsD69.11 Glanzmann thrombastheniaD69.19 Other qualitative platelet defects
I42.0-Dilated cardiomyopathyI42.00 Dilated cardiomyopathy, unspecifiedI42.01 Familial-genetic dilated cardiomyopathyI42.09 Other dilated cardiomyopathy
I42.8-Other cardiomyopathiesI42.81 Arrhythmogenic cardiomyopathyI42.89 Other cardiomyopathies not elsewhere classified
I49.8-Other specified cardiac arrhythmiasI49.81 Brugada syndromeI49.82 Ventricular bigeminyI49.89 Other specified cardiac arrhythmias not elsewhere classified
M72.2-Plantar fascial fibromatosisM72.20 Plantar fascial fibromatosis, unspecified footM72.21 Plantar fascial fibromatosis, right footM72.22 Plantar fascial fibromatosis, left foot
M86.8X1-Other osteomyelitis, shoulderM86.8X11 Other osteomyelitis, right shoulderM86.8X12 Other osteomyelitis, left shoulderM86.8X19 Other osteomyelitis, unspecified shoulder
M86.8X2-Other osteomyelitis, upper armM86.8X21 Other osteomyelitis, right upper armM86.8X22 Other osteomyelitis, left upper armM86.8X29 Other osteomyelitis, unspecified upper arm
M86.8X3-Other osteomyelitis, forearmM86.8X31 Other osteomyelitis, right forearmM86.8X32 Other osteomyelitis, left forearmM86.8X39 Other osteomyelitis, unspecified forearm
M86.8X4-Other osteomyelitis, handM86.8X41 Other osteomyelitis, right handM86.8X42 Other osteomyelitis, left handM86.8X49 Other osteomyelitis, unspecified hand
M86.8X5-Other osteomyelitis, thighM86.8X51 Other osteomyelitis, right thighM86.8X52 Other osteomyelitis, left thighM86.8X59 Other osteomyelitis, unspecified thigh
M86.8X6-Other osteomyelitis, lower legM86.8X61 Other osteomyelitis, right lower legM86.8X62 Other osteomyelitis, left lower legM86.8X69 Other osteomyelitis, unspecified lower leg
M86.8X7-Other osteomyelitis, ankle and footM86.8X71 Other osteomyelitis, right ankle and footM86.8X72 Other osteomyelitis, left ankle and footM86.8X79 Other osteomyelitis, unspecified ankle and foot
M86.8X8-Other osteomyelitis, other siteM86.8X80 Other osteomyelitis, skullM86.8X81 Other osteomyelitis, face and sinusesM86.8X89 Other osteomyelitis, other site
Z68.1-Body mass index [BMI] 19.9 or less, adultZ68.18 Body mass index [BMI] 18.4 or less, adultZ68.19 Body mass index [BMI] 18.5-19.9, adult
Z87.890-Personal history of sex reassignmentZ87.8901 Personal history of social gender transitionZ87.8902 Personal history of medical gender transitionZ87.8903 Personal history of surgical gender transitionZ87.8904 Personal history of intersex surgeryZ87.8909 Personal history of unspecified gender transition

8 of the 15 rows are the M86.8X- osteomyelitis site codes. M86.8X1- through M86.8X7- now take right, left or unspecified side, and M86.8X8- splits into skull, face and sinuses, and other site. Z68.1- is split into two adult BMI ranges and Z87.890- into 5 history codes, so both need the specific value or type from the record.

Which billable codes were deleted outright, and where do those diagnoses go now?

15 billable codes were removed with no child codes to take their place. They are not in the FY2027 code set, so they are shown here as plain text rather than links. A further 6 header codes were removed; headers were never billable, so those deletions do not affect claims.

  • Sprain of sternoclavicular (joint) (ligament): S23.420A, S23.420D, S23.420S
  • Toxic effect of other organic solvents (all four intents): T52.8X1A, T52.8X1D, T52.8X1S, T52.8X2A, T52.8X2D, T52.8X2S, T52.8X3A, T52.8X3D, T52.8X3S, T52.8X4A, T52.8X4D, T52.8X4S

For sternoclavicular sprain, the FY2027 Alphabetic Index sends both Sprain › sternoclavicular joint and Sprain › sternum › sternoclavicular to S43.6-, and category S23- carries an Excludes2 note for dislocation and sprain of the sternoclavicular joint (S43.2-, S43.6-). Subcategory S43.6 requires laterality and a 7th character, which the Index does not supply:

“The Alphabetic Index does not always provide the full code. Selection of the full code, including laterality and any applicable 7th character can only be done in the Tabular List.”
ICD-10-CM Official Guidelines for Coding and Reporting FY2027, Section I.B.1

Toxic effects of other organic solvents moved into three new subcategories under T52.8-: T52.81- (alkenes), T52.82- (cycloparaffins) and T52.89- (other organic solvents). The FY2027 Table of Drugs and Chemicals sends Alkenes to T52.811- through T52.814-, and many individual solvents, such as acetaldehyde, to T52.891- and its intent siblings. Pick the subcategory from the substance documented, not from the old code, and confirm the result in the Tabular List:

“Do not code directly from the Table of Drugs and Chemicals. Always refer back to the Tabular List.”
ICD-10-CM Official Guidelines for Coding and Reporting FY2027, Section I.C.19.e.1

How many codes were added and revised for FY2027?

FY2027 adds 190 codes. The categories with the most additions are:

  • 36 new codes in T52- (Toxic effect of organic solvents)
  • 28 new codes in O31- (Complications specific to multiple gestation)
  • 24 new codes in M86- (Osteomyelitis)
  • 16 new codes in O00- (Ectopic pregnancy)

New codes matter even when nothing you use was deleted. A new code may be a more specific choice than the code a template defaults to, and the full list of additions is worth a scan against your specialty.

4 codes keep their identifier but have a new official description: L02.232 (Carbuncle of back [any part, except buttock and flank]); L03.312 (Cellulitis of back [any part except buttock and flank]); L03.322 (Acute lymphangitis of back [any part except buttock and flank]); Z29.14 (Encounter for prophylactic rabies immune globulin). A revised code is still valid to submit. Only the wording on screens and printed forms is out of date.

What should you update in the EHR, superbills and charge master?

  • Export every stored diagnosis list. That includes EHR favourites and problem-list shortcuts, paper and electronic superbills, order-set indications, and any charge-master or template entry that carries a default diagnosis code.
  • Run each list through /check. The checker flags deleted codes, codes subdivided this year, header codes, codes that trip Medicare edit 20, and codes that are not valid in any year the site holds.
  • Replace, do not delete. Swap each subdivided code for the children your providers actually document. Keep an unspecified child available only for records that lack the detail.
  • Refresh the descriptions of the 4 revised codes wherever they are printed or cached.
  • Confirm the encoder selects the code set by date of service, so that September encounters coded in October still resolve to FY2026.
  • Read the bold text in the guidelines PDF. The FY2027 guidelines state that narrative changes appear in bold, and underlined items were moved, compared with the April 2026 FY2026 version. That formatting only survives in the PDF.

How should claims held across October 1 be re-checked?

Claims held across October 1 need to be checked in both directions. Claims for September services must keep their FY2026 codes, even where a code has since become a header. Claims for October services that were coded from September templates must be moved to FY2027 codes. Sort the held queue by date of service before editing anything.

Dilated cardiomyopathy, office visit on October 5, 2026

The superbill still offers I42.0-, which is a header in FY2027. The note documents dilated cardiomyopathy with no further detail. The Alphabetic Index entry Cardiomyopathy › dilated leads to I42.00 (Dilated cardiomyopathy, unspecified), which the Tabular List confirms is billable. If the provider documents familial-genetic dilated cardiomyopathy, the Index subterm leads to I42.01 instead.

Same diagnosis, service on September 29, 2026, claim released October 12

The FY2026 code set applies because the service came before October 1, 2026. In FY2026, dilated cardiomyopathy was reported with I42.0 as a billable code; the FY2027 addenda list it among the deleted billable codes. I42.00 did not exist on the date of service, so moving this claim to the new code would be the error.

Right sternoclavicular joint sprain, initial encounter, October 3, 2026

A template built on S23.420A fails from October 1, 2026, because the code no longer exists. The Index leads to S43.6-, and the Tabular List supplies laterality, the placeholder X and the 7th character: S43.61XA (Sprain of right sternoclavicular joint, initial encounter).

What should you check before submitting the first FY2027 claims?

Before the first FY2027 claim goes out
  • The date of service, not the billing date, sets the code set for every line.
  • No code from the subdivided list above appears on a claim for a service on or after October 1, 2026.
  • No deleted S23.420- or T52.8X- code appears on those claims.
  • New 7th-character codes, such as the T52.8 solvent codes, carry the 7th character (see the 7th character guide).
  • Held September claims were not recoded to FY2027 codes.

A pasted list takes seconds to check at /check, and each flagged code links to its FY2027 page with the replacements.

Sources

Related

Codes and descriptions are from the official ICD-10-CM FY2027 release; guideline passages are quoted verbatim. This is not billing advice — code from the provider’s documentation and the Official Guidelines. See our editorial policy or report an error.