2027 ICD-10-CM Updates: New Codes and Guideline Changes Coders Need to Know

FY2027 ICD-10-CM brings about 190 new codes, 4 revised and 30 deleted. Here are the guideline changes and key new codes coders need to know.

The FY2027 ICD-10-CM code set took effect on October 1, 2026, and the good news is that this year is a lot calmer than last year. There are new codes, a few revisions and deletions, and some guideline updates, but nothing like the last cycle. Here's what changed and what you actually need to know.

Quick disclaimer: this is an educational summary, not a substitute for your own research. Always verify against the current guidelines, the Tabular List, and your payer and facility policies, and query the provider when in doubt.

The numbers: a much smaller update

Last cycle brought 487 new codes. For FY2027 we have about 190 new codes, 4 revised and 30 deleted. That deleted count includes codes converted to parent codes, which are no longer reportable on their own because they now need additional characters.

Guideline changes

The only chapter-specific guideline updates this year are in Chapters 9, 17 and 21.

Chapter 9: Hypertension

The hypertension with heart disease guideline now says "one or more heart conditions" instead of just "heart conditions."

For hypertensive crisis, you still assign a code from category I16 (hypertensive urgency, emergency or unspecified crisis). What's new is that the instruction for coding the additional hypertensive disease now also points to the existing category I1A, alongside I10 through I15, when other hypertensive disease is identified. And I16 isn't automatically sequenced first. The principal or first-listed diagnosis still depends on the reason for the encounter.

Chapter 17: Genetic disorders join the chapter

Chapter 17 now includes genetic disorders through the new QA1 range, not just congenital malformations, deformities and chromosomal abnormalities. The coding concepts aren't new; they now explicitly apply to genetic disorders:

A Q00 through QA1 code can be principal, first-listed or secondary, depending on the encounter.
If the code identifies the condition, don't separately code manifestations inherent to it. Do code the ones that aren't.
These codes can be used throughout the patient's life. Some genetic conditions aren't diagnosed until adulthood.
For the birth admission, Z38 stays principal, followed by any applicable Q00 through QA1 codes.
If a malformation was corrected and is no longer present, use the personal history code instead.

Chapter 21: DES exposure, family vs. personal

Two new companion guidelines cover diethylstilbestrol (DES) exposure. Family history of exposure is for a patient who wasn't exposed, but a family member's exposure (the guideline's example is a maternal grandmother) creates a risk for them. Personal risk factor of exposure is for a patient exposed directly in utero, because their mother took or was exposed to DES during that pregnancy.

The way I remember it: grandma was exposed, that's family history. Mom was exposed while carrying the patient, that's personal.

New and expanded codes by chapter

Chapter 1 had no changes. Here are the highlights from the rest.

Neoplasms, blood and endocrine

Chapter 2 adds three codes for metastatic disease to the oral cavity, larynx and pharynx, which helps document speech, swallowing and airway rehab needs.

In Chapter 3, D69.1 is now a parent code, and Glanzmann thrombasthenia, a rare inherited platelet disorder, gets its own code: D69.11.

Post-bariatric hypoglycemia (PBH) finally has a home. Before, a general hypoglycemia code plus bariatric surgery status never said the hypoglycemia was a post-procedural complication. Now we have E89.830 for post-bariatric hypoglycemia and E89.838 for other post-procedural hypoglycemia. PBH means recurrent, clinically significant episodes, not every low blood sugar after surgery.

Mental health

Chapter 5 adds a code for gender identity disorder in remission. We aren't deciding whether a condition has resolved, and we aren't making assumptions based on whether someone has transitioned or detransitioned. We code what the provider documents.

Cardiology

Three familiar codes are now parent codes: I42.0 (dilated cardiomyopathy), I42.8 (other cardiomyopathies) and I49.8 (other specified cardiac arrhythmias). New specificity covers:

Familial/genetic vs. non-familial dilated cardiomyopathy. Don't stop at "dilated cardiomyopathy"; look for whether it's documented as familial or genetic.
I42.81: arrhythmogenic cardiomyopathy (ACM), the broader term for what you may know as ARVC. Other cardiomyopathies now go to I42.89.
Catecholaminergic polymorphic ventricular tachycardia (CPVT), a rare inherited arrhythmia.
I49.81: Brugada syndrome, which used to be buried in I49.8.
I49.82: ventricular bigeminy (normal beat, PVC, normal beat, PVC).
I49.89: other specified cardiac arrhythmias.

Respiratory and digestive

Odontogenic sinusitis, caused by a nearby dental infection or dental procedure, now has codes by sinus: J34.830 through J34.833, plus J34.839 when the sinus isn't specified and you can't query. Pulmonary mycetoma (a fungal ball in the lung) also gets a code. Don't confuse it with mycetoma of the skin.

On the digestive side, there are new codes for hypertrophic pyloric stenosis in childhood, prevesical and other pelvic abscess, and moderate hepatic fibrosis (staging matters more with the shift to MASLD/MASH terminology). K76.83 is new for intestinal failure-associated liver disease.

Skin and musculoskeletal

A new carbuncle of the flank code separates the flank from the back, and several back descriptions were revised to exclude the buttocks and flank. If the documentation says flank, don't treat it as back anymore.

M04.3 is new for VEXAS syndrome, a rare inflammatory disorder that mostly affects middle-aged and older biological males.
Plantar fasciitis and plantar fibromatosis no longer share a code. Plantar fasciitis moves to new codes by foot: M67.A01, M67.A02 and M67.A09. Plantar fascial fibromatosis code M72.2 was deleted and replaced by M72.20, M72.21 and M72.22, so it gets laterality too.
M86.8X (other osteomyelitis) is expanded by site, with laterality where appropriate. Pott's puffy tumor, which isn't actually a neoplasm, helped drive this. M86.8X80 now captures the skull and M86.8X81 the face and sinuses.

Genitourinary and pregnancy

Nipple ischemia and necrosis after breast procedures now have specific codes, with N99.860 for intraoperative and post-procedural nipple ischemia and a companion code for necrosis.

Ectopic pregnancy gets much more specific. New codes capture interstitial, cesarean scar, cervical and cornual sites, laterality where it applies, and whether there's a concurrent intrauterine pregnancy. One caution: interstitial and cornual aren't interchangeable. Interstitial involves the part of the tube passing through the uterine wall; cornual involves an abnormally developed uterus.

The new O31.4- subcategory, O31.40X0 through O31.43X9, identifies a continuing pregnancy after vanishing twin syndrome, by trimester, with a seventh character for the fetus.

Chapter 17: Hereditary cancer and genetic syndromes

Q87.A: Loeys-Dietz syndrome
QA1.71: Lynch syndrome
QA1.790 and QA1.791: familial cancer syndromes with pathogenic BRCA1 and BRCA2 mutations
QA1.792: Li-Fraumeni syndrome
QA1.798: other inherited neoplasm predisposition syndromes involving multiple systems

These matter because the specific syndrome can change a patient's screening and preventive care.

Lab findings and toxic effects

R78.72 is new for abnormal gadolinium levels in blood. It reflects the lab finding itself, so code any documented toxic effects separately.

Chapter 19 adds toxic effect codes by intent (accidental, self-harm, assault, undetermined), each needing a seventh character of A (initial), D (subsequent) or S (sequela):

T52.811- through T52.814- (T52.81-): alkenes
T52.821- through T52.824- (T52.82-): cycloparaffins
T59.821- through T59.824- (T59.82-): hexamethylene diisocyanate (HDI)
T65.851- through T65.854- (T65.85-): medetomidine, a veterinary sedative showing up in the illicit fentanyl supply

On the deletion side, S23.420A (sprain of sternoclavicular joint) and T52.8X1A through T52.8X4A are deleted. The solvent codes were restructured into the more specific codes above, not just removed.

Chapter 21: BMI, exposures and personal history

Low adult BMI gets split: Z68.18 for 18.4 or less, and Z68.19 for 18.5 through 19.9. Below 18.5 is generally considered underweight, which carries extra health and surgical risk.

New exposure codes include Z77.013 (gadolinium), Z77.32 (burn pits in a war theater), Z77.33 (Agent Orange), and a new group for blast overpressure. Exposure Z codes describe the circumstance, not a disease. If the patient developed a condition, code it additionally.

A resolved C. diff infection now has its own code, Z86.17 (personal history of Clostridioides difficile infection), instead of falling under the broad Z86.19 (personal history of other infectious and parasitic diseases). If the infection is active or recurrent, code that instead. The personal history of sex reassignment is now a parent code, expanded to distinguish social, medical and surgical transition, history of intersex surgery, and history of detransition. These are history codes based strictly on provider documentation.

Chapters 16, 20 and 22 had no changes.

Your action plan

Don't panic about the new codes. Do the practical stuff:

Update your EHR systems and pick lists.
Use the current code set and verify every code in the Tabular List.
Talk to providers who regularly see these conditions about documentation now.

Give them a heads-up instead of sending audit results later telling them they did it wrong. That conversation goes a lot better.

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Always verify codes against the official FY2027 ICD-10-CM code set and guidelines before you use them.

The bottom line

FY2027 is a lighter year, with guideline updates in only three chapters. The theme is specificity, especially for genetic conditions, cardiology, ectopic pregnancy and exposures. Update your tools, verify in the Tabular List, and get ahead of documentation with your providers.

Prefer to watch? The full video is embedded at the top of this post, and you can find more free tutorials on the Contempo Coding YouTube channel.