The fiscal year 2025 ICD-10-CM code set is out. CMS posted the files on July 3, and the CDC's National Center for Health Statistics has published the addenda and the updated Official Guidelines for Coding and Reporting. The totals: 252 new codes, 36 deleted codes and 13 revised code titles, all effective for dates of service on or after October 1, 2024. That gives practices ten weeks.
Ten weeks sounds like plenty. It is not, if the update involves the EHR vendor, the practice management vendor, the clearinghouse, the coders, the providers and the superbill in the drawer. Every October we see the same first-week denials: a deleted code that was still a favorite in a provider's template, a new code that the scrubber does not recognize yet, a claim that spans September 30 and October 1 with codes from both sets. All of it is avoidable, and all of it is avoidable only if someone starts in July.
Key takeaways
- The update is smaller than recent years but the families that touch office coding matter: lymphoma in remission, hypoglycemia by level, obesity by class and presymptomatic type 1 diabetes.
- Run a 12-month report of every diagnosis code you used and match it to the deletion list; every hit is a template, favorite or superbill entry that must change.
- The vendor loads the code table; your favorites, order sets, problem list mappings and paper superbills are your configuration and your job.
- The code set is chosen by date of service, not billing date, so a September 30 visit billed on October 5 still uses FY2024 codes.
- Watch CO-16 and CO-11 denials daily for the first two weeks of October and resubmit rather than downgrading a valid new code to an old one.
What is in the update for office practices
Most of the 252 new codes are specialty specific, and a family practice or an internal medicine group will use a handful. The ones we expect to touch office coding most:
- Lymphoma in remission. New codes in the neoplasm chapter distinguish lymphomas that are in remission from active disease, for Hodgkin lymphoma, follicular lymphoma and several other lymphoma types. Until now, coders had to choose between an active malignancy code and a personal history code, and neither was right for a patient in remission under surveillance. Oncology and primary care will both use these.
- Hypoglycemia by level. New codes under E16.A distinguish level 1, level 2 and level 3 hypoglycemia, following the clinical classification endocrinologists already use. Providers who document glucose values will make this easy; providers who write "low sugar" will not.
- Obesity by class. New codes under E66.81 for obesity class 1, class 2 and class 3, giving a specificity that BMI Z codes alone did not. Expect payer medical policies for weight management drugs and bariatric procedures to start referencing these.
- Presymptomatic type 1 diabetes. New codes under E10.A for early-stage type 1 diabetes identified by autoantibody screening before symptoms.
Review the full addenda for your specialty; the tabular addendum lists every added, deleted and revised code, and the guidelines addendum marks changed text. Do not rely on a vendor summary alone. Most of the 36 deletions are codes that were split into more specific children, which means a deleted code is usually replaced by two or more new ones, and the provider who used it needs to know which of the children applies to their patients.
The ten-week plan
| Weeks | Task | Owner |
|---|---|---|
| July 22 to Aug 2 | Download the addenda. Run a report of every ICD-10-CM code used in the last 12 months and match it against the deletion list. Every hit is a template, favorite or superbill entry that must change. | Coding lead |
| Aug 5 to Aug 16 | Confirm in writing when the EHR, practice management system and clearinghouse will load the FY2025 set. Ask specifically whether the update is date-of-service aware. | Practice manager |
| Aug 19 to Sep 6 | Update provider favorites, order sets, problem list mappings and paper superbills. Retire deleted codes; add the new codes your specialty will use. | Coding lead with each provider |
| Sep 9 to Sep 20 | Train providers and coders on the new codes relevant to them, with documentation examples. Update the claim scrubber edits and any payer-specific diagnosis rules. | Training lead |
| Sep 23 to Sep 30 | Test: enter a test encounter dated October 1 with a new code and confirm it passes the scrubber and the clearinghouse front-end edits. Hold any claim with a date of service on or after October 1 until the system update is confirmed live. | Billing lead |
| Oct 1 to Oct 14 | Watch the rejection and denial reports daily for CO-16 (missing or invalid information) with diagnosis remark codes, and for CO-11 (diagnosis inconsistent with procedure). | Denials staff |
A worked example: the code usage audit
The first task in the plan is the one that finds the problems, so here is what it looks like for a fictional four-provider family practice. The coding lead exports every diagnosis code billed from July 2023 through June 2024: 1,140 distinct codes across about 31,000 claims. She matches the list against the 36 deletions and the 13 revisions in the tabular addendum, and then against each provider's favorites list and the paper superbill.
| Finding | Count | Where it lives | Action |
|---|---|---|---|
| Deleted codes billed in the last 12 months | 4 codes, 610 claims | Three providers' favorites; problem list of 280 patients | Map each to its new child codes; update favorites and problem lists |
| Revised code titles in use | 2 codes, 90 claims | One order set | Confirm the revised meaning still fits the documentation |
| New codes the practice should adopt | 9 codes | Not yet anywhere | Add to favorites; write one documentation example each |
| Superbill entries affected | 3 lines | Paper superbill, last revised 2022 | Reprint before September 30 |
| Scrubber edits referencing changed codes | 2 payer rules | Claim scrubber configuration | Update with the billing vendor |
Six hundred and ten claims on deleted codes is about 2% of the practice's volume. Left alone, that is roughly 50 rejected claims a month from October, each of which costs a touch to fix and a delay in payment, and the 280 problem list entries would keep generating the dead code every time a provider pulled a diagnosis forward. The audit took the coding lead about four hours. That is the whole argument for starting in July.
The date-of-service rule
The code set that applies is determined by the date of service, not the date the claim is submitted. A visit on September 30 uses FY2024 codes even if it is billed on October 5. A visit on October 1 uses FY2025 codes even if it is billed the same day the update goes live. For inpatient stays, the discharge date governs. Practices that submit a batch on October 2 with mixed dates need a system that knows the difference; most do, but confirm it, because a system that applies the new set to everything will reject valid September claims. The same rule applies in reverse to late charges and corrected claims: a corrected claim for an August visit submitted in November still carries FY2024 codes.
Mistakes we see every October
The provider who keeps typing a deleted code because it is muscle memory, producing a week of rejections before anyone notices. The superbill nobody updated because the practice "doesn't use paper anymore" except on the one day the system is down. The payer that loads the new codes late and rejects valid claims for two weeks, which is not your fault but is your problem; keep those claims and resubmit rather than rewriting the diagnosis to an old code. The problem list that nobody cleaned, so every pulled-forward diagnosis is a dead code. And the coder who learns the new codes but not the guideline changes, which are where the audit risk lives.
Questions we hear
Do we have to use the more specific new codes, or can we keep coding the way we do?
When a more specific code exists and the documentation supports it, coding guidelines expect you to use it. Unspecified codes remain valid where the documentation is genuinely unspecific, but payers increasingly deny or request records on unspecified codes where a specific one is available.
Our EHR vendor says the update is "automatic". Is that enough?
It is enough for the code table. It is not enough for your favorites, templates, order sets, problem lists and superbills, which are your configuration, not the vendor's. Ask the vendor for the date the table loads and do the configuration work yourself or with your billing partner.
Where can our staff learn the changes properly?
Our live online RCM training runs an FY2025 ICD-10-CM update session before October 1, and the Revelrex EHR training environment lets coders practice the new codes on fictional encounters before they touch a live claim. Practices on our medical billing service receive the template and superbill review as part of the annual update.
What to do this month
- Download the FY2025 tabular addendum and guidelines addendum from the CDC site and give them to the coding lead.
- Export every diagnosis code billed in the last 12 months and match it against the deletion and revision lists.
- For each hit, list where the code lives: favorites, order sets, problem lists, superbills, scrubber rules.
- Email the EHR, practice management and clearinghouse vendors asking for the load date and whether the update is date-of-service aware; keep the replies.
- Pick the new codes your specialty will use and write one documentation example for each.
- Put the September 23 test encounter and the October 1 daily denial review on the calendar now.
