What is hospital billing?
Hospital billing is the process that gathers everything done during patient care, applies the fee schedules and rules of the payer contract and sends the claim for payment in the TISS standard. It's one of the steps of the hospital revenue cycle: it starts after care is documented and ends when the claim is accepted, denied or paid.
Billing depends on what happens before it. A technically flawless claim will still be denied if the procedure had no authorization or the member was inactive. That's why efficient billing is billing that receives complete information from the previous steps and feeds every error back to them.
What makes up a hospital claim?
A hospital claim brings together daily rates, fees, drugs, supplies, OPME (orthoses, prostheses and special materials), medical gases, tests, procedures and physician fees, each item with its code and price according to the contract.
See the figures as a table
| Revenue type | % of gross revenue (2024) |
|---|---|
| Other operating revenue | 26,13% |
| Daily rates and fees | 24,48% |
| Drugs | 21,34% |
| Materials | 14,31% |
| OPME | 7,61% |
| Other service revenue | 4,53% |
| Donations | 0,84% |
| Medical gases | 0,76% |
Since more than two thirds of revenue comes from items billed one by one [1], every drug or supply that isn't recorded, isn't coded correctly or isn't in the contract becomes lost revenue or a denial. In OPME, a single item can be high-value, which explains why these items usually require prior authorization and go through detailed audits.
What are the steps of hospital billing?
Billing has six steps, from checking what was documented to reconciling the payment. The first three depend only on the hospital; they decide whether the claim will be accepted on first review.
| Stage | What happens | Where it usually gets stuck |
|---|---|---|
| 1. Pre-billing | Checking authorizations, forms and member data while the patient is still admitted | Expired code or extension not requested, discovered only after discharge |
| 2. Claim review and audit | Reviewing the medical record against what will be billed: items recorded, quantities, justifications | Claim stalled waiting on another department |
| 3. Coding and pricing | Each item receives its TUSS code and the price from the fee schedule negotiated in the payer contract | Outdated fee schedule in the system; contract rule not configured |
| 4. Closing and form generation | The claim is closed (in full or in part, for long stays) and the TISS forms are generated | Late closing; form with an empty required field |
| 5. Batch submission | Forms are grouped into a batch and sent to the payer in the TISS standard, within the contract deadline | Batch rejected for a file error; late submission |
| 6. Follow-up and reconciliation | Reading the claim review and payment statements, checking the amount paid and routing denials to appeal | Underpayment not identified |
Interim closing. For long stays, the contract may allow billing the claim in parts, by period. This brings revenue forward and avoids very large claims that are hard to audit. Rules and frequencies vary from contract to contract.
The time between discharge and submission belongs to the hospital. Every day a claim waits on an internal issue adds to the collection period, which at Anahp hospitals was 77.35 days in 2025 [2]. Measuring this interval separately shows how much of the delay is the hospital's and how much is the payer's. See the Hospital average collection period guide.
What is the TISS standard and how does it organize billing?
The TISS standard (Private Healthcare Information Exchange) is ANS's mandatory standard for administrative information exchange between payers and providers, currently governed by RN 501/2022 [4]. It defines the forms, electronic messages, codes and security rules used from the authorization request to the payment statement [3].
| TISS standard component | What it defines |
|---|---|
| Organizational | The operating rules for information exchange |
| Content and Structure | The data structure of each form and electronic message |
| Representation of Health Concepts | The unified terminology, TUSS, with codes for procedures, supplies, drugs, daily rates and messages |
| Security and Privacy | Protection of the information exchanged |
| Communication | Transmission means and protocols |
ANS updates the standard periodically, and each component has its own version. The Organizational Component defines what may only be exchanged electronically: billing, the attachments batch, admission and discharge notices, the statements and the denial appeal. For eligibility and authorization, electronic exchange is optional [3]. The version in force and the implementation calendar are on the TISS standard page of the ANS website [3]. Keeping the hospital's system on the required version avoids having entire batches rejected.
TISS standard forms. Each type of care uses its own form [3]:
| Guide | When it's used |
|---|---|
| Consultation form | Elective consultations |
| SP/SADT form | Tests, therapies, outpatient procedures and emergency department care; for an inpatient, only when the service is outsourced |
| Admission request | Authorization request to admit |
| Inpatient summary | Billing for the admission and the fees billed by the hospital; daily rates, fees, supplies, drugs, medical gases and OPME go on the other expenses attachment |
| Physician fee form | Billing for fees when the professional bills the payer directly; linked only to the admission request |
| Other expenses attachment | Daily rates, fees, supplies, drugs, medical gases and OPME; it has no number of its own and is linked only to an SP/SADT form or an inpatient summary |
| Dental treatment | Dental care |
| Denial appeals | Contesting the denials reported by the payer |
Forms are sent in batches, and the payer responds with the claim review statement (what it accepted and what it denied) and the payment statement. Details on each form are in the TISS claim forms guide, and the full standard in the TISS standard guide.
TUSS tables: the codes for each item on the claim
TUSS (Unified Private Healthcare Terminology) is the TISS standard component that gives a unique code to each item billed. The tables most used in hospital billing are [3]:
| TUSS table | Content |
|---|---|
| 18 | Daily rates, fees and medical gases |
| 19 | Supplies and OPME |
| 20 | Drugs |
| 22 | Procedures and health events |
| 38 | Messages, including denial reasons |
The code comes from TUSS, but the price comes from the contract: Law 9,656/1998, art. 17-A, requires the written contract with the payer to include the prices of services [5]. Each payer negotiates its own price schedule with the hospital; for supplies and drugs, contracts usually reference market price publications, and for physician fees, medical reference schedules, always with the percentages and exceptions agreed between the parties. That's why the same item can have different prices for each payer, and the hospital's system needs every contract configured. See the TUSS table guide.
The billing errors that most often become denials
Many denials come from errors that could be caught before submission. The most common in billing are:
| Error | How it shows up | How to prevent |
|---|---|---|
| Item without authorization or beyond what was authorized | Procedure, OPME or daily rate billed without a valid code | Check authorizations at pre-billing, before discharge |
| Item billed without a medical record entry | Supply or drug on the claim that doesn't appear in the care record | Reviewing the claim against the medical record |
| Incorrect TUSS code | Nonexistent, outdated code or one for another item | Up-to-date TUSS tables in the system and automated validation |
| Price outside the contract | Amount different from the fee schedule negotiated with the payer | Configured contracts, with current terms and adjustments |
| Duplicate billing | The same item billed twice, on the same form or on different forms | Automated duplicate rule before submission |
| Form or batch with errors | Empty required field, file outside the TISS standard version | XML validation before submission |
| Late submission | Claim submitted after the contract deadline | Deadline tracking by payer |
ZG Soluções' 2026 Revenue Cycle Panorama, with data from the company's client institutions, attributed 67.9% of the denied amount to avoidable failures [7]. The cheapest way to reduce these denials is to review claims before submission; see the Medical claims auditing guide and the Hospital claim denials guide.
Billing deadlines: what the law says
ANS doesn't set a single deadline for the hospital to bill or for the payer to pay. Law 9,656/1998, art. 17-A, requires the written contract between payer and provider to set billing and payment deadlines and procedures [5]. RN 503/2022 details the mandatory content of these contracts, including denial-related deadlines [6].
In practice, this means each payer may have a different claim submission deadline, its own payment calendar and specific resubmission rules. Having each contract's deadlines in the system, with alerts, avoids missing the submission deadline, one of the easiest denials to avoid. See the RN 503/2022: the payer contract guide.
Billing KPIs
| Indicator | How to calculate | What it shows |
|---|---|---|
| Discharge-to-submission time | Average days between discharge and claim submission | How much of the delay is internal |
| Unbilled claims | Value of discharged patient claims not yet submitted | Revenue produced and stuck in the hospital |
| First-pass acceptance | Amount accepted without denials ÷ amount submitted | Quality of the claim submitted |
| Batch rejections | Batches rejected ÷ batches submitted | Technical file and version problems |
| Denials for billing reasons | Amount denied for code, price, duplicate or deadline ÷ amount submitted | Errors billing itself can fix |
| Average collection period | (Health plan receivables ÷ health plan revenue for the period) × days | Total time until the money arrives |
The full formulas and industry benchmarks are in the Revenue cycle KPIs guide.
What we see in operations
At Accrua, we start from one principle: billing depends on the quality of the information that comes from other departments. That is why Accrua OS reads the whole claim before submission (medical record, prescriptions, items, OPME and bundles) and checks it against each health plan's contract, current price table and authorization rule. What is missing or inconsistent goes back to its source before it becomes a denial.
The platform works on top of the hospital's existing management system, with no re-keying. Agents handle XML validation, batch submission and deadline and status tracking. Billers and auditors with nursing training or a nursing specialization handle the decisions that change value and the open items that require talking to other departments.
We measure the time from discharge to submission by claim type and by health plan, because that is the stretch where the hospital has the most control over its own days to payment. And what a health plan denies on one claim feeds the review of the next.
Where to start
- Measure discharge-to-submission time and the value of unbilled claims; that's the delay that depends only on the hospital.
- Review contract configuration: price schedules, effective dates, adjustments, submission deadlines and each payer's rules.
- Do pre-billing during the stay, checking authorizations and extensions before discharge.
- Audit claims before submission, ideally all of them, with automated rules for duplicates, codes and prices.
- Read the review statement for each batch and send each denial back to the department that caused it.