TISS 4.01: what changed and how to adapt your billing

TISS is the mandatory standard that governs the electronic exchange of information between healthcare providers (such as clinics and hospitals) and health plans. It defines how forms must be structured, which fields must be filled in and how clinical and administrative data flow among the players in private healthcare. The ANS requires everyone involved in care and payment to adopt it.

Version 4.01 is the direct successor of TISS 4.0, released in March 2021. The update consolidated technical adjustments accumulated over three years of use of the standard, focusing on the precision of terminologies, data security and aligning the organizational components with the industry’s operational needs.

Since December 31, 2024, adopting version 4.01 has been mandatory. Earlier versions can no longer be used in any electronic information exchange in private healthcare. Hospitals still running the previous version are out of compliance with ANS requirements and exposed to form rejections and denials.

What changed in version 4.01

Version 4.01 concentrates its main changes in the terminologies. The ANS revised four tables of the Health Concept Representation component, TUSS, which is the set of codes used to identify procedures, materials and medications on electronic forms.

The modified tables were:

• Table 19 — Materials and OPME: new and revised terms for orthotics, prosthetics and special materials (OPME), high-value items with a high risk of denial when coded incorrectly or with outdated codes.

• Table 20 — Medications: updated terms identifying the drugs used in billed procedures.

• Table 22 — Health Procedures and Events: revision of the codes that identify the procedures performed and billed on the forms.

• Table 64 — How procedures and care items are sent to the ANS: adjustments to how care items are classified and sent to the regulator.

Beyond the terminologies, version 4.01 revised the Organizational component, which defines the standard’s operating rules, and adjusted the Communication component, which governs the means and methods for sending electronic messages between providers and payers.

Monthly updates: what they are and why you should track them

In addition to version 4.01, the ANS now publishes monthly updates to the TISS standard. These updates mainly affect the TUSS terminologies, with terms added, revised and removed in the materials, medications and procedures tables.

The May 2025 version, for example, added nearly 26,000 new terms to the OPME table and 334 terms to the medications table. These are significant volumes that directly affect form coding and, consequently, billing.

A hospital operating with outdated tables risks using codes that the ANS has revised or replaced. This kind of mismatch between what the provider sends and what the payer recognizes is one of the most frequent causes of technical denials and automatic form rejections.

Keeping systems in sync with the current version of the TISS standard should be an operational routine.

What the hospital needs to review

Adapting to version 4.01 and the subsequent monthly updates involves three main fronts: systems, tables and processes.

Systems and integrations

The first step is to confirm that the hospital management system and the integrations with payers are certified for version 4.01. The ANS provides the e-TISS environment, where electronic form submission can be tested and validated before official transmission. Using this environment before going live reduces the risk of batch rejections.

Internal tables

Tables 19, 20, 22 and 64 must be up to date in the internal systems and in the TPAs (Third Party Administrators) the hospital uses. Since the ANS publishes monthly versions, the ideal is to set up a periodic update workflow, with a designated owner on the IT or billing team.

Processes and team

The technical review of systems must go hand in hand with updated operating processes. Billing teams need to know the new codes and the rules of the revised Organizational component, especially in high-volume billing areas such as OPME and oncology.

The impact on billing and denials

An outdated TISS standard affects the hospital revenue cycle at two critical points: submission and payment.

At submission, forms with codes from earlier versions may be automatically rejected by payers before they even reach audit. This creates rework for the billing team, delays payment and puts the contractual deadline at risk.

At payment, even forms that pass initial submission may be denied in the payer’s audit because of a mismatch between the code used and the current terminology. This type of technical denial is especially harmful because it tends to be identified late, when the appeal deadline is about to expire.

In high-value specialties such as OPME and oncology, the financial impact of incorrect coding can be significant. A single form with a material or medication billed under a revoked code can mean a full denial of the item, even when the procedure was correctly performed and documented.

Keeping the TISS standard up to date is therefore a direct way to protect hospital revenue.

TISS compliance and revenue protection: the role of technology

Tracking monthly changes to the TISS standard requires organization, well-defined processes and integrated systems. For hospitals with high billing volumes, any mismatch between the version in use and the current version translates into avoidable denials and lost or withheld revenue.

Rivio works across the entire hospital billing cycle, ensuring that the forms sent to payers always comply with the current standard. With artificial intelligence technology and specialized human support, the platform reduces the risk of technical rejections and keeps the hospital protected with every ANS update.