A coder we work with opened the CDC download page on Tuesday morning expecting the usual April batch of new codes to load into the practice management system. There wasn't one. The April 1, 2025 ICD-10-CM update contains zero new diagnosis codes, zero deletions and zero code revisions. Her first reaction was relief. Her second was the right one: if there are no new codes, why did the CDC post new files at all?
The answer is that the April update carries a change to the Official Guidelines for Coding and Reporting and a set of wording corrections to the index and tabular list. None of them show up on a "new codes" report. One of them changes which patients get a particular diagnosis code, and that has downstream effects on quality reporting, risk adjustment and payer edits.
This is the fourth April cycle since CMS made the mid-year update a fixed part of the calendar (the first April release was April 1, 2022, with three new codes), and most practices still treat it as optional. It isn't. Here is what is in it and what to do about it this month.
Key takeaways
- The April 1, 2025 update adds, deletes and revises no codes, but it changes the COVID-19 guideline: U07.1 now requires a provider-documented diagnosis, and a positive test result alone no longer supports the code.
- The tabular list gains "use additional code" notes pointing to E88.A (cachexia) under tuberculosis and under pneumoconiosis associated with tuberculosis, plus spelling corrections such as jirovecii.
- Guideline changes never appear in a code delta file, so a practice that only loads code files never sees them. Someone has to read the document.
- Lab-only and nurse-only encounters are where the COVID-19 change bites in an office; fix the pick lists that turn a result into a diagnosis.
- The same routine (confirm the vendor load, read the guideline text, review favorites, watch rejections) is the one that makes the October update painless.
What actually changed on April 1
The CDC posted updated code files and a revised guidelines document dated for April 1, 2025. The substantive items are short enough to list in full:
- COVID-19 confirmation. The guideline for U07.1 (COVID-19) now says to code only a confirmed diagnosis as documented by the provider. The earlier guidance, in place since 2020, allowed a positive test result alone to stand as confirmation. From April 1, a positive result in the chart without a provider statement of the diagnosis is not enough to assign U07.1. The guideline also tells coders to query the provider when an asymptomatic patient tests positive, because false positives happen and the diagnosis belongs to the clinician.
- Use additional code notes. The tabular list adds "use additional code" instructions under tuberculosis (A15 to A19) and under J65 (pneumoconiosis associated with tuberculosis) pointing coders to E88.A, wasting disease (syndrome) due to underlying condition, when cachexia is present.
- Spelling and typography. Several index and tabular entries were corrected, including the organism name under B59 pneumocystosis (jiroveci becomes jirovecii). These do not change code assignment, but they do change what a search in your encoder returns.
That is the whole list. It is a small update, but small updates are where practices get careless.
Who the COVID-19 change affects
The change was written with long-term care in mind, where routine surveillance testing produces positive results in residents who have no symptoms. Skilled nursing facilities have to query the attending provider before assigning U07.1 to an asymptomatic resident. But the same logic applies in the office.
Think about how COVID-19 gets coded in an ambulatory practice today. A patient with a cough gets a rapid antigen test at the front of the visit. The result is positive. The provider documents "URI symptoms, COVID positive, supportive care" and the coder assigns U07.1. Under the new guideline, that documentation is probably fine because the provider stated the result in the assessment. Where it fails is the lab-only encounter: a nurse visit for a test, a result that posts to the chart, a claim built from the lab order, and U07.1 attached because a positive result came back. From April 1, that encounter should carry Z20.822 (contact with and suspected exposure to COVID-19) or Z11.52 (encounter for screening for COVID-19) unless the provider documents the diagnosis.
Why it matters for revenue: U07.1 feeds quality measures, some payers' care management triggers and, in Medicare Advantage, risk adjustment reviews. A payer auditing charts for a diagnosis that is not supported by a provider statement will treat it as unsupported, and an unsupported diagnosis on a claim is a compliance problem even when it did not change the payment.
A worked example
A family practice runs 40 COVID-19 tests a month at the front desk. Say 8 come back positive. In 5 of those the provider sees the patient and writes the diagnosis in the assessment; those 5 encounters carry U07.1 under both the old and the new guideline. In the other 3 the patient was tested at a nurse visit, the result posted to the chart, and the claim for the test (87811 or 87426, depending on the test) went out with U07.1 as the only diagnosis because the superbill favorite said "COVID positive". From April 1 those 3 claims should carry Z20.822 or Z11.52 instead. Nothing about the payment for the test changes. What changes is that the practice stops putting an unsupported confirmed diagnosis on 36 claims a year, and stops feeding those 36 into every downstream registry and risk adjustment file that reads U07.1.
How to run a mid-year code update in a practice
Practices that handle the October update well often have no process at all for April, because "nothing changed". This is the process we recommend regardless of how big the update is.
| Step | Who | What to check |
|---|---|---|
| Confirm the vendor loaded the update | Practice manager or billing lead | Ask your EHR and practice management vendor in writing which ICD-10-CM version is active. The April files carry a version date; some vendors skip April if there are no new codes and load only the guidelines in October. |
| Re-read the guideline changes | Coding lead | Compare the April guidelines document with the October version. This year it is one section. Circulate the change to providers whose documentation is affected. |
| Review favorites and superbills | Coding lead with each provider | Look for pick-list entries that encode a lab result as a diagnosis. Rename or retire any favorite that assigns U07.1 from a test. |
| Check clearinghouse and payer edits | Billing lead | Run the rejection report daily for the first two weeks of April. A vendor that loaded a wrong or partial file produces "invalid diagnosis code" rejections immediately. |
| Update the training file | Coding lead | Add the change to the coder onboarding notes so new hires learn the current rule, not the 2020 rule. |
The numbers to watch this month
Three numbers tell you whether the update landed cleanly. First, clearinghouse rejections with a diagnosis-related reason (invalid code, code not effective for date of service) in the two weeks after April 1, compared with the two weeks before. Any increase is a file problem. Second, the count of claims carrying U07.1 by encounter type. If nurse-only or lab-only encounters still carry it after April 1, the pick lists were not fixed. Third, payer denials with CARC CO-16 (claim lacks information) or CO-11 (diagnosis inconsistent with procedure) trending up for a single payer, which usually means that payer's edits updated on a different schedule than yours.
The mistakes we see
The first mistake is assuming "no new codes" means "no work". Guideline changes do not appear in a code delta file, so a practice that only loads codes never sees them. The second is letting the EHR vendor be the only source of truth. Vendors load files on their own timetable, and their release notes rarely mention guideline text. The third is treating the CDC guideline as a hospital problem. The Official Guidelines apply to every setting that reports ICD-10-CM, including physician offices, and payers audit against them.
We think the mid-year update is a good moment for something else as well: a quick look at how the practice codes diagnoses from results generally. COVID-19 is the example in the guidelines this year, but the same habit shows up with positive urine cultures coded as urinary tract infection, or an elevated A1c coded as diabetes before the provider has said so. The rule has always been that the provider makes the diagnosis and the coder reports it. April is a good time to say that out loud again.
Looking ahead to October
CMS usually posts the fiscal year code files in June, and the fiscal year 2026 set takes effect October 1, 2025. The habit you build now, confirming the vendor load, reading the guideline text, reviewing favorites and watching the rejection report, is the same habit that makes the October update painless. Practices that want a second set of eyes on coding, or that need help building the update routine, can see how our medical coding service handles code set maintenance, or look at the live RCM training calendar for the next coding session.
Questions we hear
Do we have to re-code claims from before April 1?
No. Guidelines apply by date of service. An encounter on March 28 follows the October 2024 guidelines; an encounter on April 1 follows the April version. Do not go back and change claims that were correct under the rule in force when the service happened.
Our payer still lists U07.1 as acceptable from a positive test. Which rule wins?
The Official Guidelines are the standard under HIPAA for ICD-10-CM reporting. A payer policy can be more restrictive than the guidelines but should not be less. If a payer's written policy conflicts, follow the guidelines and keep a copy of the payer policy in case of a dispute.
Is there a grace period for the April update?
Medicare does not offer one for ICD-10-CM changes, and most commercial payers follow Medicare. Since there are no new codes this cycle, the only thing that can go wrong is a documentation habit, and that is fixed with a conversation rather than a file load.
What to do this month
- Get written confirmation from your EHR and practice management vendors that the April 1, 2025 files and guidelines are loaded.
- Read the one changed guideline section and send providers a three-sentence note: U07.1 requires your documented diagnosis, a positive result alone is not enough, and here is what to write.
- Search every favorites list and superbill for entries that assign U07.1 from a test and retire them.
- Run the diagnosis-related rejection report daily through April 15 and compare it with March.
- Pull all claims with U07.1 for dates of service after April 1 and check the encounter type; fix any lab-only or nurse-only claims before they are paid.
