ICD-11 in Brazil: what changes in hospital billing

ICD-11, the 11th revision of the International Classification of Diseases, takes effect in Brazil in January 2027. The date has already been set by Ministry of Health Technical Note No. 91/2024, and hospitals, clinics and billing teams need to prepare for a change that directly affects diagnosis coding, claim validation and the revenue cycle.

For billing managers and hospital controllers, understanding what changes and what needs to be done before 2027 is a financial decision, not just a technical one.

What ICD-11 is and why it represents an important change

The International Classification of Diseases is the global system for coding diagnoses, diseases and health conditions published by the World Health Organization (WHO). The version currently in force in Brazil is ICD-10. ICD-11 was adopted by the WHO at the 72nd World Health Assembly in May 2019 and took effect internationally on January 1, 2022.

The new version brings about 17,000 unique codes for injuries, diseases and health conditions that, combined, describe up to 1.6 million distinct clinical situations, according to the Ministry of Health. For comparison, ICD-10 has approximately 14,400 codes. The expansion is not only quantitative: the structure of ICD-11 was redesigned to work in a digital environment, with more flexible coding hierarchies and integration with electronic health systems.

In Brazil, the Portuguese translation was completed in February 2024, in a process coordinated by the Federal University of Minas Gerais (UFMG) with support from the Ministry of Health and the Pan American Health Organization (PAHO/WHO). As a result, for the first time, the Portuguese version of the ICD is available on the WHO’s official platform.

Comparison between ICD-10 and ICD‑11

Implementation timeline in Brazil

Brazil opted for a planned, phased transition based on the guidelines of the WHO’s ICD-11 Transition Guide. The main milestones are:

• 2021: formal start of the national implementation process.

• February 2024: Portuguese translation completed, coordinated by UFMG with support from the Ministry of Health and PAHO/WHO.

• 2024 to 2026:field testing, professional training and updating of health information systems.

• January 2027: ICD-11 begins to be used in health surveillance systems, under Ministry of Health Technical Note No. 91/2024. Full adoption may extend into 2028.

The longer timeline compared with the international effective date (2022) has two main reasons. The first is technical: the WHO recommends that the last version of the previous ICD be up to date for at least two years before migration, and Brazil only finished updating to the 2019 version of ICD-10 at the end of 2025. The second is operational: the scale of the Brazilian health system, with hundreds of hospitals, different ERPs and the complexity of SUS (Brazil’s public health system) and private healthcare, requires a gradual transition process.

From a global perspective, Brazil is actually ahead: Australia plans adoption in 2031; England has not set a mandatory date before 2028; the United States is still analyzing the impact, with no official timeline.

How ICD-11 affects hospital billing

For billing teams, the transition to ICD-11 has direct consequences on four fronts:

Diagnosis coding

Every hospital claim sent to a payer or to SUS must have its diagnoses correctly coded. With ICD-11, the codes change structure: they leave the alphanumeric format of ICD-10 (e.g., J18.9) behind and adopt a new standard with greater specificity. Coders and billing specialists will need to be trained in the new logic before 2027 to avoid coding errors that lead to denials.

Denial risk during the transition period

During the transition, the risk of denials due to code incompatibility increases. Health plans and SUS will need to update their own audit systems to accept the new codes. Hospitals that migrate before their payers or that make mapping errors between ICD-10 and ICD-11 will face claim rejections that did not exist before.

Concurrent auditing becomes even more relevant in this scenario: checking whether the recorded diagnosis is correctly coded while the patient is still in the hospital reduces the risk of submitting claims with incompatible codes.

Data quality and financial management

ICD-11’s greater diagnostic specificity enables more precise financial analysis. With more granular diagnoses, the manager can identify which specialties or types of procedure generate the most denials, what the average cost per patient profile is and where there is waste or underbilling. This turns ICD-11 into a financial intelligence tool, not just a compliance one.

Updating systems and contracts

Hospital ERPs, billing systems and contract tables with payers will need to be updated before 2027. Contracts that reference ICD-10 codes to define coverage, waiting periods or authorized procedures will need review. The sooner this mapping starts, the lower the risk of operational disruption at the January 2027 changeover.

What the hospital needs to do before January 2027

With less than two years until mandatory adoption, the priority actions are:

• Map the affected systems:the ERP, electronic medical record, billing system and XML submission platforms need to be assessed to identify what requires updating.

• Train coders and billing specialists:ICD-11 coding logic is different from ICD-10. Training should begin before the adoption date so that professionals can work confidently from day one.

• Audit the ICD-10 to ICD‑11 mapping:the most frequent diagnoses on the hospital’s claims should be mapped to the new codes in advance, reducing errors during the transition period.

• Review contracts with payers:identify clauses that reference ICD-10 codes and start negotiating amendments when necessary.

• Monitor Ministry of Health publications:the timeline may be adjusted, and new technical notes should be followed by the hospital’s regulatory and compliance teams.

ICD-11 as an opportunity to strengthen the revenue cycle

The transition to ICD-11 requires operational effort, but it represents a concrete opportunity to strengthen the hospital revenue cycle. More specific diagnoses produce more accurate claims, with a lower risk of incompatibility denials and more support for the hospital’s financial management.

Hospitals that start preparing now, investing in training, system updates and auditing of code mappings, will reach 2027 with processes ready to operate under the new classification. Those that wait will face the cost of the transition with less time and a greater risk of disruption to the billing flow.

Artificial intelligence platforms such as Rivio already read and interpret clinical records automatically. With the arrival of ICD-11, this capability becomes even more strategic: AI can check whether the recorded code matches the diagnosis documented in the medical record, reducing coding errors before the claim is sent to the payer.

Frequently asked questions about ICD‑11

Is ICD-11 already in use in Brazil?

Not yet. Brazil still uses ICD-10 (2019 version). The adoption of ICD-11 is scheduled for January 2027, under Ministry of Health Technical Note No. 91/2024.

What changes in practice for hospital billing?

Diagnosis codes change structure. Claims submitted with an ICD-10 code after ICD-11 is adopted may be rejected by payers. Training coders and updating billing systems are actions that need to happen before 2027.

How many more codes does ICD-11 have than ICD‑10?

ICD-11 brings about 17,000 unique codes, compared with approximately 14,400 in ICD-10. Combined, these codes describe up to 1.6 million distinct clinical situations.

Have other countries already implemented ICD‑11?

Few countries have completed implementation. Australia plans adoption in 2031; England has no mandatory date before 2028; Germany will adopt it partially from 2027. Brazil is in line with the average global pace of transition.

Is Rivio already prepared for ICD‑11?

Rivio’s platform works with automated reading of clinical records and cross-checking against hospital claims. The transition to ICD-11 is being monitored to ensure that automated auditing continues to identify coding discrepancies with the necessary precision.