The ICD-10-CM updates 2026 mid-year release includes 47 new codes, 18 revised code descriptors, and 9 deleted codes effective July 1, 2026. CMS published these corrections on May 15, 2026, to address gaps in clinical specificity and reflect updated medical terminology for conditions like long COVID, monkeypox sequelae, and vaping-related lung injury. Coders have less than 30 days to implement these changes across documentation workflows, encoder software, and billing systems before claims using outdated codes trigger denials.
Most healthcare organizations focus on the October annual update cycle and miss the mid-year release entirely. That's a mistake. These corrections apply immediately. Claims coded after July 1 with deleted codes will reject at the clearinghouse. Revenue cycle teams need to act now.
What changed in the mid-2026 ICD-10-CM release
CMS released the mid-2026 update to correct clinical documentation gaps identified during the first quarter of 2026. The changes fall into four categories: new codes for emerging conditions, revised descriptors for clarity, deleted duplicate codes, and updated inclusion terms.
The 47 new codes address conditions that weren't adequately captured in the October 2025 update. You'll see new codes for:
- Post-acute sequelae of COVID-19 affecting specific organ systems (12 new codes under U09)
- Mpox (monkeypox) complications and sequelae (8 new codes)
- E-cigarette or vaping product use-associated lung injury subtypes (6 new codes)
- Drug-induced movement disorders from GLP-1 agonists (4 new codes)
- Specific complications of weight loss medications (5 new codes)
The 18 revised descriptors don't change the code itself but clarify what the code captures. For example, code J84.178 previously read "Other interstitial pulmonary diseases with fibrosis in diseases classified elsewhere." The revised descriptor now reads "Interstitial pulmonary fibrosis secondary to systemic disease," which better reflects how physicians document the condition.
The 9 deleted codes were duplicates or codes that created coding conflicts. If you're using these codes in your encoder favorites or documentation templates, remove them before July 1. Claims submitted with deleted codes after the effective date will reject.
Long COVID coding gets more specific
The October 2025 update introduced U09.9 for post-COVID conditions, but it was too broad. Clinicians couldn't distinguish between cardiac, pulmonary, neurological, or other organ-specific sequelae.
The mid-2026 release adds 12 new codes under the U09 category. Each code specifies the organ system affected:
- U09.0 — Post-COVID-19 pulmonary fibrosis
- U09.1 — Post-COVID-19 myocardial dysfunction
- U09.2 — Post-COVID-19 cognitive dysfunction
- U09.3 — Post-COVID-19 dysautonomia
- U09.4 — Post-COVID-19 chronic fatigue syndrome
The remaining 7 codes cover renal, hepatic, hematologic, and multi-organ involvement. Code U09.9 remains valid for unspecified post-COVID conditions, but you'll need clinical documentation specifying the affected system to use the new codes.
This matters for risk adjustment. Medicare Advantage plans calculate HCC scores based on documented chronic conditions. Generic post-COVID coding doesn't capture severity. Organ-specific codes do. If your risk adjustment coding team isn't tracking these changes, you're leaving revenue on the table.
Documentation requirements for post-COVID codes
You can't assign these codes based on patient-reported symptoms alone. The physician must document a causal relationship between prior COVID-19 infection and the current condition. Acceptable documentation includes:
- Physician statement that the condition is a sequela of COVID-19
- Clinical correlation between symptom onset and prior documented COVID infection
- Diagnostic test results supporting organ-specific dysfunction (PFTs for pulmonary, echocardiogram for cardiac, cognitive testing for neurological)
If the documentation says "patient reports fatigue since COVID infection" without physician assessment, you can't code it. The physician needs to evaluate, document findings, and establish the link.
Vaping-related lung injury codes expand
The original EVALI (e-cigarette or vaping product use-associated lung injury) code U07.0 didn't differentiate between acute respiratory failure, organizing pneumonia, or diffuse alveolar damage. Radiologists and pulmonologists document these as distinct clinical presentations, but coders had no way to capture the specificity.
The mid-2026 update adds 6 new codes under a new U07.2x subcategory:
- U07.20 — EVALI with acute respiratory failure
- U07.21 — EVALI with organizing pneumonia
- U07.22 — EVALI with diffuse alveolar damage
- U07.23 — EVALI with lipoid pneumonia
- U07.24 — EVALI with hypersensitivity pneumonitis
- U07.29 — EVALI, other specified type
Code U07.0 remains valid for unspecified EVALI, but payers increasingly deny claims coded to unspecified categories when more specific codes exist. If the radiology report or pulmonology note specifies the type of lung injury, code it.
These codes apply to both inpatient and outpatient encounters. For inpatient coding, the specific EVALI code may function as the principal diagnosis if it's the reason for admission. Always sequence according to UHDDS definitions and coding guidelines.
Drug-induced movement disorders from weight loss medications
GLP-1 receptor agonists (semaglutide, tirzepatide) went mainstream in 2024. By early 2026, neurologists started reporting movement disorders in patients on long-term therapy. The existing G25.7x codes for drug-induced movement disorders didn't allow specificity by drug class.
CMS added 4 new codes under G25.7:
- G25.75 — Drug-induced dystonia due to GLP-1 agonist
- G25.76 — Drug-induced tremor due to GLP-1 agonist
- G25.77 — Drug-induced parkinsonism due to GLP-1 agonist
- G25.78 — Other drug-induced movement disorder due to GLP-1 agonist
You still need to code the GLP-1 medication using a T code for adverse effect (not poisoning). The correct sequence is the movement disorder code first, then the appropriate T code with a 5th or 6th character of 5 (adverse effect), then the Z code for the specific medication.
Example: A patient develops tremor while taking semaglutide for type 2 diabetes. Code sequence: G25.76 (tremor due to GLP-1), T38.3X5A (adverse effect of insulin and oral hypoglycemics, initial encounter), Z79.84 (long-term use of oral hypoglycemic drugs).
Check your outpatient coding templates. Many organizations still default to generic G25.79 (other drug-induced movement disorder). Update your encoder favorites and superbills before July 1.
Why this matters for medical malpractice and adverse event reporting
Specific codes for drug-induced conditions feed into FDA adverse event databases and manufacturer pharmacovigilance programs. Underreporting these conditions delays safety warnings and regulatory action. If your organization uses GLP-1 agonists frequently (endocrinology, bariatric medicine, cardiology), train coders to watch for movement disorder documentation and code it accurately.
Deleted codes you need to remove from workflows
Nine codes were deleted because they duplicated existing codes or created coding conflicts. Using a deleted code after July 1 will cause claim rejection. Your encoder software should flag these automatically if you've updated to the mid-2026 code set, but manual coders and documentation templates won't catch them without active review.
The deleted codes include:
- I63.02 — deleted, replaced by more specific laterality codes
- K76.81 — deleted, merged into K76.89
- M54.18 — deleted, use M54.17 instead
- R91.2 — deleted, replaced by R91.8
The full list of 9 deleted codes appears in the CMS May 2026 addendum published on CMS.gov. Don't rely on this summary alone. Pull the official file and cross-check your most frequently used codes.
If your organization uses pre-populated encounter forms, dot phrases in the EHR, or coding macros, audit them now. A deleted code embedded in a template will cause every claim using that template to deny after July 1.
Implementation timeline and compliance deadlines
The mid-2026 ICD-10-CM changes take effect July 1, 2026. That's the date of service, not the date the claim is submitted. Any encounter dated July 1 or later must use the updated code set.
You have until June 30 to:
- Update encoder software to the mid-2026 code set
- Review and revise documentation templates, dot phrases, and pre-populated forms
- Train coding staff on new codes and revised descriptors
- Update charge capture systems and superbills for outpatient services
- Notify physicians of new codes requiring more specific documentation
Most EHR vendors push ICD-10 updates automatically, but verify the update installed correctly. Run a test claim with one of the new codes to confirm your system accepts it. If you're still on a legacy system or using standalone encoder software, you may need to download and install the update manually.
Claims clearinghouses will reject claims using deleted codes starting July 1. Unlike the October annual update, CMS doesn't provide a grace period for mid-year releases. The effective date is firm.
Frequently asked questions about mid-2026 ICD-10-CM changes
Do mid-year ICD-10-CM updates happen every year?
No. CMS publishes mid-year updates only when clinical documentation gaps or coding conflicts need immediate correction. The last mid-year update before 2026 was in April 2020 for COVID-19 codes. Most years see only the October annual update.
Can I still use unspecified codes like U09.9 for post-COVID conditions after the mid-2026 update?
Yes, but only when the documentation doesn't specify the organ system affected. If the physician documents "post-COVID pulmonary fibrosis," you must use U09.0, not U09.9. Payers increasingly deny claims coded to unspecified categories when specific codes exist and documentation supports them.
How do the new GLP-1 movement disorder codes affect HCC risk adjustment?
They don't directly map to HCC categories, but they improve diagnostic specificity for patients with multiple chronic conditions. Better documentation of drug-related complications supports medical necessity for alternative treatment plans and may justify higher complexity evaluation codes. The movement disorder itself doesn't add HCC weight, but the underlying conditions requiring the medication (diabetes, obesity, heart failure) do.
What happens if I submit a claim with a deleted code after July 1?
The claim will reject at the clearinghouse or payer level. You'll receive a rejection notice stating the code is invalid. You'll need to correct the code and resubmit, which delays payment. If you're submitting paper claims (rare but still happens), the payer will return the claim unprocessed.
Where can I download the official mid-2026 ICD-10-CM code files?
CMS publishes all ICD-10-CM updates on the CMS.gov ICD-10 page. Look for the "2026 Code Descriptions — Addendum" file dated May 2026. The file includes new codes, revised descriptors, deleted codes, and updated inclusion terms. Most encoder vendors pull directly from this file, but you should verify your vendor installed the update correctly before July 1.
What to do before July 1
You have 3 weeks. Start with a system audit. Check that your encoder software, EHR, and billing system all reflect the mid-2026 code set. Test a claim with a new code to confirm it processes without errors.
Next, review your coding workflows. If you use pre-populated forms, templates, or macros, check them for deleted codes. A single outdated template can cause dozens of denials before anyone notices.
Train your coding team. Run a 30-minute session covering the new long COVID codes, EVALI subtypes, and GLP-1 movement disorders. Focus on documentation requirements. Coders can't assign these codes without physician statements establishing causality.
Notify your providers. Physicians don't track mid-year coding updates. If they're documenting post-COVID conditions generically, they need to know the new codes exist and require organ-specific language. A quick EHR message with examples works better than a policy memo nobody reads.
Finally, set a calendar reminder for September. The October 2026 annual update will include additional changes, and you'll need time to prepare. Don't let mid-year updates derail your October readiness.
If your coding team is already stretched thin and you're worried about implementation gaps, talk to MedCodex Health. We handle mid-year updates for clients as part of standard service. Your team stays focused on production while we manage the compliance details. MedCodex Health offers a free coding assessment to identify gaps in your current update process. No obligation, just a clear view of where you stand before the July 1 deadline.