Every fall, medical coders brace for the same ritual: a fresh batch of ICD-10-CM codes rolls out, and suddenly the charts you coded in September need a second look come October. This year is no different. CMS has released the fiscal year (FY) 2027 ICD-10-CM code set, and it goes live on October 1, 2026.
The headline numbers: 238 new codes, 4 revised codes, and 21 deleted codes. That might sound like a lot to absorb, but most of the changes cluster around a handful of specialties — oncology, cardiology, dermatology, OB/GYN, and a few new additions for rare and emerging conditions.
Below is a plain-English breakdown of what’s changing, organized by body system, so you can quickly find what applies to your specialty and update your coding workflows before the effective date.
Oncology and Blood Disorder Updates
Secondary (metastatic) cancer codes get more specific. The C78.- (secondary malignant neoplasm of respiratory and digestive organs) and C79.- (secondary malignant neoplasm of other and unspecified sites) categories are picking up three new codes. The goal is simple: let coders document exactly where a cancer has metastasized, rather than defaulting to a vaguer catch-all code.
Platelet defect coding is splitting into two paths. The old D69.1 (qualitative platelet defects) inclusion terms are being retired and redistributed into two new, more precise codes:
- D69.11 – Glanzmann thrombasthenia (covers Glanzmann’s disease and hereditary hemorrhagic thrombasthenia)
- D69.19 – Other qualitative platelet defects (covers Bernard-Soulier/giant platelet syndrome, grey platelet syndrome, and thrombocytopathy)
If you’ve been defaulting to D69.1 out of habit, it’s time to build the new codes into your templates.
Breast cancer + carcinoma in situ can no longer be coded together. Right now, coders can report a C50.- (malignant neoplasm of breast) code alongside a D05.- (carcinoma in situ of breast) code for the same patient. Starting October 1, that combination is off the table. Expect this to affect coding logic and payer edits, so flag it for your compliance team.
New Codes for Postprocedural Hypoglycemia
Low blood sugar after surgery finally gets its own dedicated codes:
- E89.83 – Postprocedural hypoglycemia following a procedure
- E89.830 – Post-bariatric hypoglycemia
- E89.838 – Other postprocedural hypoglycemia
This is a meaningful upgrade for bariatric and general surgery coders who previously had to rely on less specific hypoglycemia codes.
Cardiology: Dilated Cardiomyopathy Gets a Genetic Split
I42.0 (dilated cardiomyopathy) is expanding into three distinct codes:
- I42.00 – Dilated cardiomyopathy, unspecified
- I42.01 – Familial-genetic dilated cardiomyopathy
- I42.09 – Other dilated cardiomyopathy
This split reflects a broader trend in ICD-10-CM toward capturing genetic etiology separately from unspecified or “other” presentations — useful for both clinical tracking and research purposes.
Odontogenic Sinusitis Finally Gets Its Own Code
Dental-related sinus infections have long been a documentation gray area. That changes with new subcategory J34.83- (Odontogenic sinusitis). Coders will need a 6th character to specify which sinus is involved: maxillary, ethmoid, frontal, or sphenoid.
Gastrointestinal (K Code) Additions
Three notable additions land in the digestive system chapter:
- K31.B – Hypertrophic pyloric stenosis, in childhood
- K6A.- – Diseases of the pelvis, not elsewhere classified
- K74.0A – Hepatic fibrosis, moderate fibrosis (equivalent to stage F2 liver fibrosis)
The K74.0A addition is particularly useful for hepatology and GI coders who need to document fibrosis staging more precisely.
Skin and Soft Tissue Code Changes
One new code and three revisions are coming to the integumentary chapter:
- New: L02.237 – Carbuncle of flank
- Revised: L02.232 – Carbuncle of back (any part, except buttock and flank)
- Revised: L03.312 – Cellulitis of back (any part, except buttock and flank)
- Revised: L03.322 – Acute lymphangitis of back (any part, except buttock and flank)
Essentially, “flank” is being carved out as its own anatomical descriptor rather than being lumped in under “back.”
Musculoskeletal Updates: Plantar Fasciitis, Osteomyelitis, and VEXAS Syndrome
- M67.A- – A new category for plantar fasciitis and plantar fascial fibromatosis, giving coders a dedicated home for these common foot conditions instead of relying on nonspecific fasciitis codes.
- M86.8X- – Additional osteomyelitis codes now require a 7th character to specify laterality (right, left, or unspecified).
- A brand-new M code is being added for VEXAS syndrome, a rare and serious autoinflammatory disease that develops in adulthood and causes the immune system to attack the body’s own tissues. This is a good one to flag for rheumatology practices.
OB/GYN and Congenital Condition Updates
This is one of the busier sections in the 2027 update:
- New subcategory N99.86- – Intraoperative and postprocedural complications and disorders of the breast
- 56 new codes for ectopic pregnancy, offering far more granularity than the current code set
- New category O31.4- – Continuing pregnancy after vanishing twin syndrome (one or more fetuses)
- New congenital malformation codes for Loeys-Dietz syndrome, Lynch syndrome, and Li-Fraumeni syndrome
Practices handling high-risk pregnancies or genetic counseling should review these closely, since several of these codes will likely see frequent use.
New Code for Abnormal Gadolinium Levels
Under R78.7- (finding of abnormal level of heavy metals in blood), a new code — R78.72 (abnormal gadolinium level in blood) — is being added. This is relevant for facilities tracking gadolinium retention following contrast-enhanced MRI scans.
Code Deletion: Sternoclavicular Sprain
S23.420- (sprain of sternoclavicular joint/ligament) is being deleted in FY 2027. Make sure this is removed from any outdated code lists, superbills, or EHR templates.
Toxic Effects: New Alkene Poisoning Codes
The toxic effects section is expanding with new codes starting with T52.81- (toxic effects of alkenes), adding more precision for coding chemical exposure cases.
Z Code Revisions: More Specificity Around Sex and Gender Reporting
The 2027 Z code changes are a mixed bag — some codes stay exactly as they are, some get sharper descriptors, and a few broader categories split into multiple, more specific options. One notable theme in this year’s update is increased specificity and sensitivity in how sex and gender-related information is reported, giving coders more accurate ways to document these details.
What Coders Should Do Before October 1, 2026
- Update your encoder software and code lists as soon as the final code set is loaded into your system.
- Flag the C50/D05 bundling change for your coding and compliance teams, since it directly affects claims logic.
- Retrain staff on the new platelet defect codes (D69.11/D69.19) and the dilated cardiomyopathy split (I42.00/I42.01/I42.09), since these replace commonly used existing codes.
- Review OB/GYN templates, especially if your practice handles ectopic pregnancies or high-risk genetic conditions.
- Remove S23.420- from any superbills, cheat sheets, or EHR quick-pick lists before the deletion takes effect.
Where to Learn More
CMS has posted the full FY 2027 ICD-10-CM code set on its website. For a deeper dive, Revenue Cycle Insider subscribers can access a more comprehensive breakdown, and AAPC is publishing an in-depth feature in its September issue of AAPC the Magazine, along with a webinar scheduled for September 23, 2026.
