What is interim billing?
Interim billing (conta parcial in Portuguese) means billing one period of an inpatient stay while the patient is still in the hospital. Instead of waiting for discharge to build a single claim, the hospital closes the stay in blocks (for example, every 10, 15 or 30 days) and sends each block to the health plan (operadora, the company that sells and manages private health plans in Brazil). The last claim, from the last cutoff to discharge, is the final claim.
Brazil's TISS standard (Troca de Informações na Saúde Suplementar, the mandatory electronic data exchange standard between providers and health plans, set by the regulator) handles the stay through linked forms (guias). The admission request opens the stay, the extension request lengthens the authorized period and the inpatient summary (Resumo de Internação) bills it, always referencing the initial request [4]. In interim billing, each inpatient summary reports the billing type from table 55 of TUSS (Terminologia Unificada da Saúde Suplementar, the unified code set used in TISS) [1].
Interim billing is one of the closing methods described in the pillar guide Hospital billing, which covers the full path of a claim, from assembly to payment.
Partial, final, supplementary and total: when to use each type
Table 55 gives only the names of the four types [1]. Their working meaning comes from established market practice and each health plan's manual, so the rule should be confirmed in the contract.
| TUSS 55 code | Type | Usually used for | Main point of care |
|---|---|---|---|
| 1 | Partial | One period of the stay, with the patient still admitted | Clear cutoff date and time; authorized period |
| 2 | Final | The last period, from the last interim claim to discharge | Do not repeat items already billed in interim claims |
| 3 | Supplementary | Items left out of a claim already sent (for example, a physician fee or a supply posted late) | Confirm whether the contract accepts it and by when |
| 4 | Total | The whole stay in a single claim, from admission to discharge | Use only when there was no interim claim |
Flagging the wrong type is easy and costly. Sending as “total” a claim that closes a stay already billed in interim claims, or as “partial” the discharge claim, confuses the health plan's review and can trigger a denial for invalid billing (message 1713) [3].
Who decides how often to send interim claims?
The contract does. Law 9,656/1998, article 17-A, paragraph 2, requires the written contract between health plan and provider to include, among its mandatory clauses, the deadlines and procedures for billing and paying for services [5]. The law does not set a number of days for any of this. Normative Resolution (RN) 503/2022 of the National Supplementary Health Agency (ANS, Brazil's regulator of private health plans) details what the contract must contain. In article 14, it requires the audit routine, the grounds for denial (claim denial) and the deadlines for appeal, response and payment after reversal [6]. Anahp (Associação Nacional de Hospitais Privados, the national association of leading private hospitals) notes in its contracting manual that ANS does not set payment deadlines [7].
In practice, the rules vary a lot. One public example is an annex to a 2024 hospital accreditation notice from Conab, a federal agency that buys health services for its staff. It requires long stays to be closed in interim claims, each identified by its order (1st, 2nd and so on), and does not accept an interim claim shorter than ten days, except when the stay is closed [10]. Each health plan may have its own rule, and the same plan may handle each contract differently.
Before billing in interim claims, five questions need a written answer in the contract or the health plan's manual:
| Question | Why it matters |
|---|---|
| Are interim claims accepted? For which types of stay? | Without a contract clause, the interim claim may be returned |
| What is the minimum and maximum period of each interim claim? | An interim claim that is too short may be rejected |
| Does the submission deadline run from the cutoff or from discharge? | Determines whether the interim claim expires before discharge |
| How are bundles and physician fees handled? | A fixed-price item cannot be split without a rule |
| Are supplementary claims accepted? Until when? | A missed item may become a permanent loss |
The guide Hospital–payer contract shows how to negotiate these clauses.
What the hospital gains from interim billing
Interim billing brings cash forward and shrinks each claim review. Anahp's figures help size it. The average collection period of its member hospitals was 77.35 days in 2025 [8]. Anahp measures this period from the issue of the invoice (nota fiscal) [11]: the days while the stay remains open and unbilled are left out of it and add to the real time until the money comes in.
The average length of stay at Anahp hospitals was 3.76 days in 2025 [8]. For a typical stay, interim billing makes no difference. It matters for long stays: in Q2 2026, the average length of stay was 11.99 days in the neonatal ICU, 6.05 in the pediatric ICU and 5.10 in the step-down unit at Anahp hospitals [9]. These 2026 figures use a new patient-day concept and should not be compared with earlier years [9].
The operational gains also count:
- Smaller reviews. A ten-day claim is checked faster and with fewer errors than a two-month claim.
- Earlier denials. The statement for the first interim claim shows what the health plan challenges, and the hospital corrects documentation in the following periods.
- Less deadline risk. Older items from a long stay do not wait until discharge to be billed.
Billing too often also has a cost: more batches, more statements to reconcile and more cutoffs to get wrong. The balance usually lies in the interval the contract allows and the team can close with quality.
How do you close an interim claim, step by step?
Closing an interim claim follows the same logic as the discharge claim, with one extra point: the cutoff date and time.
See the claim types as a table
| Claim | Type (TUSS 55) | Period |
|---|---|---|
| 1st interim claim | 1 · Partial | Admission to 1st cutoff (date and time) |
| 2nd interim claim | 1 · Partial | 1st to 2nd cutoff, extension approved |
| Final claim | 2 · Final | Last cutoff to discharge |
| Supplementary | 3 · Supplementary | Missed item, if the contract allows |
| Total | 4 · Total | The whole stay in a single claim, no interim claims |
- Set the cutoff date and time. Everything up to the cutoff goes into the interim claim; everything after it goes into the next one. Record the cutoff in the system before the review starts.
- Check that the period is authorized. Every billed day must be covered by the initial authorization or by an approved extension. The request uses the TISS extension form (Solicitação de Prorrogação de Internação ou Complementação do Tratamento) [4]; the steps are in the guide Inpatient stay extensions.
- Count the per diems for the period. The count follows the contract's per diem rule and must match the entry and exit dates of each unit. Billing rules are in the guide Hospital daily rates and fees.
- Post only the items from the period. Supplies, drugs, fees, tests and physician fees dated within the interval. An item dated outside the interval goes to the right interim claim or to the final claim.
- Build the inpatient summary with the billing type. Flag “partial” (code 1 in table 55) and reference the same admission request [1][4]. State the order of the interim claim if the contract asks for it. How to fill in each form is covered in the guide TISS claim forms.
- Send it in the batch and record the protocol number. Electronic billing submission is mandatory in the TISS standard [4].
- Reconcile the interim claim's statement before closing the next one, and use the denials to correct the following periods.
At discharge, the final claim covers the last cutoff to the patient's exit, flagged as “final” (code 2) [1].
The precautions that prevent denials on interim claims
The precautions that prevent denial center on the handover between one claim and the next, where the same item can be billed twice or never billed at all. TUSS table 38 has specific messages for these cases, checked in the ANS database on October 17, 2026 [2][3].
| Risk | Table 38 message the health plan may use | How to prevent it |
|---|---|---|
| Same period billed in two interim claims | 3232: duplicate claim for a period already submitted in another interim claim (in effect 12/01/2025) | Cutoff with date and time, no overlap; log of interim claims already sent |
| Item posted again in the next interim claim or the final claim | 3209: duplicate procedure or item (in effect 12/01/2025) | Posting by date of service; system lock for items already billed |
| Physician fee billed in two claims | 2607: duplicate physician fees (in effect 12/01/2025) | Fee tied to the procedure date |
| Per diems beyond the authorized period | 1917: no extension for the number of per diems billed (in effect 12/01/2025) | Extension approved before closing the interim claim |
| Items from unauthorized days | 3188: item in an unauthorized stay (in effect 12/01/2025) | Same precaution: close the interim claim only on authorized days |
| Per diem count that does not match the dates | 3189: item quantity incompatible with the length of stay (in effect 12/01/2025) | Check entry, transfer and cutoff dates and times |
| Wrong billing type | 1713: invalid billing | Check the table 55 code before sending |
Two precautions have no code but carry weight:
- Bundles. If the stay was contracted as a bundle, splitting it into interim claims depends on an express contract rule. See the guide Hospital bundles.
- Missed items. A supply posted after the cutoff must go in the next interim claim, the final claim or, if the contract allows, a supplementary claim. Without a rule, the item becomes a loss.
The meaning of other messages is in the guide TISS denial codes. Daily control of authorization, clinical notes and extensions in long stays is the subject of the guide ICU and long-stay denials.
How do you track interim claims after submission?
Each interim claim is a claim in its own right: it has a protocol number, a review period, a statement and possibly an appeal. For each long stay, the hospital needs to know how many interim claims were sent, which were paid and which have denials under discussion.
Three indicators help. The first is the number of stays open longer than one contracted period with no interim claim sent, which shows stalled revenue. The second is denials under messages 3232, 3209 and 2607, which measure cutoff quality. The third is the time between each cutoff and the submission of the interim claim, the same logic as the guide Discharge-to-bill time. Reading the health plan's response is covered in Claim review and payment statements, and the cash effect in Hospital average collection period.
What we see in operations
For long stays, Accrua treats interim billing as a calendar routine. The billing interval comes from each health plan's contract, loaded into Accrua OS, and agents track the cutoff dates of every open stay so the interim claim goes out on time, without waiting for discharge.
Before submission, each interim claim is read in full and compared with the earlier ones for the same stay. Matching periods, daily rates and items looks for the duplicate billing that TUSS table 38 covers under code 3232, and confirms that the billing type from table 55 is right. After submission, reconciliation tracks each interim claim on the remittance statement, separate from the others.
When a long stay weighs on cash, Receita Garantida can put the value of eligible production into the hospital's cash on the schedule it needs, with risk read by health plan, plan and claim type. Adjusting an interim claim already sent, or accepting a denial on it, is a person's decision.
Where to start
- Map each health plan's interim billing rule: acceptance, minimum and maximum period, submission deadline and supplementary claims.
- List stays open longer than one contracted period and check whether the interim claim was sent.
- Standardize the cutoff date and time and record it in the system before the review.
- Set the system to block items already billed in a previous interim claim.
- Measure denials 3232, 3209 and 2607 over the last 12 months, by health plan, and take the cases to the denials committee.