ICD-10-CM 2027 Updates: Everything Medical Coders Need to Know Before October 1
If you code claims for a living, mark your calendar — the fiscal year 2027 ICD-10-CM code set is officially live on the CMS website, and it goes into effect October 1, 2026. This year’s update isn’t as massive as some previous ones, but it still packs a punch: 238 new codes, 4 revisions, and 21 deletions that will touch several specialties. If you want the fuller code-by-code breakdown, our complete FY 2027 ICD-10-CM code list covers every addition, deletion, and revision in one place, and it’s worth comparing against the proposed 2027 code changes that CMS released earlier in the cycle.
Inpatient coders should also keep an eye on the companion procedure code set — see our guide to the ICD-10-PCS FY 2027 updates for what’s changing on the procedural side before the same October 1 effective date.
Below is a plain-English breakdown of what’s changing, organized by chapter, so you can update your cheat sheets and EHR templates before the new fiscal year hits.
Cancer and Blood Disorder Coding Gets More Precise
Coders who deal with oncology claims will notice that secondary malignancy reporting is tightening up. The C78.- (secondary malignant neoplasm of respiratory and digestive organs) and C79.- (secondary malignant neoplasm of other and unspecified sites) categories are each picking up three new codes so you can document metastatic sites with more anatomical detail than before.
There’s also a small-but-important change buried in the blood disorder chapter. D69.1 (Qualitative platelet defects) is being retired and split into two new, more specific codes:
- D69.11 – Glanzmann thrombasthenia, which now covers Glanzmann’s disease as well as hemorrhagic and hereditary thrombasthenia
- D69.19 – Other qualitative platelet defects, which picks up Bernard-Soulier (giant platelet) syndrome, grey platelet syndrome, and thrombocytopathy
If platelet and clotting disorders aren’t your everyday coding territory, our thrombocytopenia ICD-10-CM coding guide is a useful refresher on the surrounding blood disorder codes.
And here’s one that could actually change your workflow: starting October 1, you’ll no longer be able to report a C50.- (malignant neoplasm of breast) code alongside a D05.- (carcinoma in situ of breast) code for the same patient. If both conditions are present, you’ll need to pick the code that best reflects the diagnosis rather than reporting them together, as many coders have done up to now.
Three New Codes for Postprocedural Low Blood Sugar
Post-surgical hypoglycemia finally gets its own dedicated home in the E-code chapter:
- E89.83 – Postprocedural hypoglycemia following a procedure
- E89.830 – Post-bariatric hypoglycemia
- E89.838 – Other postprocedural hypoglycemia
This is a welcome change for facilities that do a lot of bariatric surgery, since it removes the guesswork around how to document low blood sugar that shows up after the operation.
Cardiology: Dilated Cardiomyopathy Gets Split Out
Cardiac coders will want to pay close attention here. 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 lines up with a broader trend in the 2027 update: CMS is pushing coders toward documenting the type of a condition rather than just the general diagnosis, which usually means providers will need to be more specific in their notes too. Coders who also work heart failure claims may want to bookmark our heart failure ICD-10-CM coding guide and our nonischemic cardiomyopathy ICD-10 coding guide alongside this update, since dilated cardiomyopathy often overlaps with both.
A New Category for Odontogenic Sinusitis
Sinusitis caused by dental issues finally gets recognized as its own diagnosis. The new subcategory J34.83- (Odontogenic sinusitis) requires a 6th character to specify which sinus is involved — maxillary, ethmoid, frontal, or sphenoid.
New K-Codes Worth Bookmarking
A few additions are landing 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 (this is the code to use for a stage F2 liver fibrosis diagnosis)
That last one is especially useful for hepatology and GI practices that track fibrosis staging, since it closes a documentation gap that’s existed for a while. For a deeper look at staging and sequencing liver conditions, check out our liver failure ICD-10 coding guide.
Skin and Soft Tissue Code Refinements
There’s one new addition and three revisions in this chapter:
- L02.237 – Carbuncle of flank (new code)
- 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] (revised)
Essentially, the “flank” is being carved out as its own distinct anatomical site rather than being lumped in under general back codes.
Plantar Fasciitis Gets Its Own Category
Foot and ankle coders will be glad to see M67.A- (Plantar fasciitis), along with new codes for plantar fascial fibromatosis. Previously, these conditions had to be coded using less specific alternatives, so this is a straightforward win for orthopedic and podiatry practices. If you need a refresher on how this condition was coded before the update, our plantar fasciitis ICD-10 coding guide is a good place to start.
Osteomyelitis and a New Code for VEXAS Syndrome
The M86.8X- (Other osteomyelitis) category is expanding, and you’ll need a 7th character to note whether the affected structure is unspecified, right-sided, or left-sided.
Also worth flagging: a brand-new code is being added for VEXAS syndrome, a rare and serious autoinflammatory disease that typically shows up in adulthood and causes the immune system to attack the body’s own tissue. Given how recently VEXAS was identified as a distinct condition, this addition should make a real difference for rheumatology practices that have been stuck using nonspecific codes.
OB/GYN Chapter Sees a Big Jump in New Codes
This is one of the larger updates in the entire code set. Coders working in OB/GYN and maternal-fetal medicine should expect:
- A new subcategory, N99.86-, for intraoperative and postprocedural complications and disorders of the breast
- 56 new codes for ectopic pregnancies
- A new category, O31.4-, for continuing pregnancy after vanishing twin syndrome affecting one or more fetuses
The ectopic pregnancy expansion in particular is significant given how much documentation detail is now required — practices should plan to update their templates well before the effective date. In the meantime, our existing ectopic pregnancy ICD-10 coding guide and ectopic/molar pregnancy ICD-10, CPT, and ICD-10-PCS coding guide are good starting points for the current rules, and OB/GYN coders should also check the 2027 CPT coding changes for obstetric care since procedural coding is shifting alongside these diagnosis codes.
New Codes for Hereditary Syndromes
The congenital malformation chapter is picking up new, more specific codes for several hereditary conditions, including:
- Loeys-Dietz syndrome
- Lynch syndrome
- Li-Fraumeni syndrome
These conditions are increasingly showing up in genetic testing and oncology screening workflows, so having dedicated codes should cut down on “unspecified” reporting.
A 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 matters for radiology and nephrology practices monitoring patients who’ve had repeated contrast-enhanced MRIs, since gadolinium retention has become a bigger clinical concern in recent years.
One Deletion to Note: Sternoclavicular Sprain
Not everything is being added — S23.420-, Sprain of sternoclavicular (joint) (ligament), is being deleted in the FY 2027 update. Make sure this code is pulled from any saved templates or superbills before October 1.
Expanded Toxic Effects Codes
The toxicology chapter is growing too, starting with new codes under T52.81- (Toxic effects of alkenes). Coders in emergency medicine and toxicology should keep an eye on the full CMS addenda for the complete list of additions in this section. For the broader rules around this chapter, see our guides to toxic effects coding in ICD-10-CM (T51–T65) and poisoning, adverse effects, toxic effects, and underdosing coding.
Z-Codes: More Specificity Across the Board
The Z-code changes for 2027 are a mixed bag compared to 2026. Some codes stay exactly the same, some get slightly reworded descriptors, and others are broken out from broad categories into more specific, reportable options. One area getting particular attention this year is the reporting of patients’ sex and gender, where the 2027 update introduces greater specificity and sensitivity than previous versions.
What Coders and Billing Teams Should Do Now
With the effective date just around the corner, here’s a quick checklist:
- Update your encoder and EHR code libraries ahead of October 1, 2026.
- Flag the C50/D05 change for your oncology coding team specifically — this one changes existing workflow, not just adds a code.
- Retrain staff on the new hypoglycemia, ectopic pregnancy, and osteomyelitis code sets, since these involve multiple new options rather than a single straightforward addition.
- Audit templates for the deleted sternoclavicular sprain code so it doesn’t get pulled into a claim after the cutover.
- Watch for provider documentation gaps — several of these new codes (dilated cardiomyopathy, hepatic fibrosis staging, VEXAS syndrome) require a level of clinical specificity that may not currently be showing up in physician notes.
The FY 2027 ICD-10-CM update takes effect October 1, 2026, so there’s time to prepare — but with 238 new codes to absorb, the sooner your team starts reviewing these changes, the smoother the transition will be.
Related Reading for Medical Coders
- FY 2027 ICD-10-CM Code Updates: New, Deleted, and Revised Codes
- 2027 ICD-10-CM Proposed Code Updates
- ICD-10-PCS FY 2027 Updates: What Coders Need to Know
- 2026 ICD-10-CM Updates: 487 New Codes & Major Revisions
- Top 7 Changes in the FY 2026 ICD-10-CM Codes
- 2027 CPT Coding Changes for Obstetric Care
