Hospital auditing: what is it and how is it done?

Hospitals that serve health plans deal every day with a constant financial risk: billing less than they produced. Hospital auditing exists to close that gap. It helps ensure that every procedure performed is recorded correctly, billed with documentary support and paid in full by the payer.

The process covers medical claims, medical records, authorizations, materials, medications and nursing records. When any of these elements fails, the payer issues a denial, and the hospital loses revenue it had already produced.

What is hospital auditing?

Hospital auditing is the systematic review of medical claims, medical records, prescriptions and documents generated during patient care. Its central goal is to verify whether what the hospital recorded and billed complies with current care, ethical, legal and contractual standards.

The process involves cross-checking clinical information against the entries in the billing system and answers questions such as:

• Was the medication prescribed the same one administered?

• Does the number of daily rates billed match the length of the hospital stay?

• Do the procedures performed have a clinical justification documented in the medical record?

Every uncorrected inconsistency becomes a denial, that is, a refusal of payment issued by the payer. According to data from the Anahp (National Association of Private Hospitals) Observatory, Brazilian private hospitals record denial rates that can exceed 10% of gross billing, a direct hit to the institution’s cash.

Hospital auditing acts precisely at this point: before the claim is submitted, identifying and correcting failures that, without review, turn into lost revenue.

To understand how these losses build up along the care cycle, see the article Claim denials: what they are and how to avoid them.

What are the types of hospital auditing?

Hospital auditing can take different forms, depending on the timing and goal of the review: prospective, concurrent and retrospective audit.

Prospective audit

It is done before care or admission. The auditor assesses whether the procedures requested have clinical justification and are within the health plan’s rules.

Example: a patient needs elective surgery. The prospective audit reviews the physician’s request and either authorizes it or not.

Concurrent audit

It takes place during the patient’s hospital stay. The auditor follows the medical record and the consumption of materials in real time.

Example: if a patient receives expensive antibiotics, the auditor checks whether there is an adequate medical prescription and whether the drug is being used correctly.

Retrospective audit

It happens after the patient’s discharge, with a detailed check of the hospital claim before it is sent to the health plan.

Example: checking whether the number of daily rates billed matches exactly the time the patient was in the hospital.

Internal vs. external audit: what is the difference?

Beyond the types defined by timing, hospital auditing is also divided by the auditor’s origin. Understanding this distinction is essential for managers who need to structure the institution’s financial governance.

Why is hospital auditing essential for billing?

Hospital billing is the process of turning the services provided into revenue by billing the payers. This transformation depends on one fundamental condition: that clinical records are correct, complete and compatible with the contractual rules of each health plan.

When there are failures in this chain, part of the revenue is lost to denials. Hospital auditing acts as a filter between the delivery of the service and the submission of the claim, reducing the chances of refusal by payers.

In practice, it contributes to billing by:

• confirming that all procedures performed were recorded in the medical record and entered into the system;

• checking whether charges comply with the rules of the National Supplementary Health Agency (ANS), the regulator that sets the rules for coverage and billing in private healthcare;

• identifying coding errors before they cause denials;

• detecting duplicate charges or items with no clinical justification.

Every denial avoided is revenue that reaches the hospital’s cash without the need for long dispute processes. To understand how to structure this process, see the article Denial appeals: how to control and recover amounts.

How is hospital auditing done in practice?

The hospital auditing process involves several steps. Here are the main ones:

1. Document collection: the auditor gathers medical records, prescriptions, nursing reports, test results and invoices.

2. Information check: the clinical data are checked against what was recorded in the billing system.

3. Comparison with price tables: the amounts billed are checked against tables such as the CBHPM (Brazilian Hierarchical Classification of Medical Procedures) or SIMPRO (Health Products Information System).

4. Identification of inconsistencies:failures are located, such as medications billed without a prescription or discrepancies between tests requested and tests performed.

5. Corrections and adjustments: the claim is made correct before it goes to the payer, reducing the chance of a denial.

6. Submission to the health plan: once adjusted, the claim is forwarded for billing and collection.

What are the main failures that hospital auditing identifies?

The most common inconsistencies found during hospital auditing have varied causes but a similar financial impact: lower revenue and more administrative rework.

• Missing clinical justification: a test or procedure billed without a medical indication documented in the medical record. This is one of the main causes of technical denials.

• Duplicate charges: the same item entered more than once in the billing system, whether due to human error or poor integration between systems.

• Coding error: incorrect use of TUSS (Unified Terminology for Supplementary Health) codes, which define the billable procedures in private healthcare. A wrong code can cause a denial even when the procedure was performed correctly.

• Mismatch between prescription and charge: a medication billed at a dose, presentation or quantity different from what was prescribed and administered.

• Administrative denials: failures in prior authorizations, submission deadlines or documentation required by the payer, regardless of the clinical quality of care.

These failures directly compromise the hospital revenue cycle and, when they recur, point to a structural weakness in the billing process.

Why does working in hospital billing require knowledge of auditing?

Anyone who works in hospital billing needs to understand the principles of hospital auditing. That is because the two areas are complementary: billing depends on correct records, and auditing ensures those records are compliant.

Some typical functions of the hospital billing department:

• Checking medical forms and authorizations.

• Putting together complete hospital claims.

• Applying the correct procedure and medication codes.

• Sending XML files to payers.

Without hospital auditing, hospital billing is vulnerable to denials and payment delays.

What are the main failures that hospital auditing finds?

• Missing clinical justification: when a test or procedure has no clear medical indication.

• Duplicate charges: the same item entered more than once.

• Coding error: incorrect use of procedure codes.

• Mismatch between prescription and charge:a medication prescribed at a dose different from the one billed.

• Administrative denials: failures in authorizations, deadlines or documentation.

These failures have a direct impact on hospital billing and can compromise the institution’s sustainability.

Tips for improving hospital billing through auditing

1. Train teams: professionals well trained in clinical records and billing make fewer errors.

2. Standardize processes: create internal protocols for medical records and billing.

3. Use technology: management software and AI reduce human error.

4. Track indicators: monitor denial rates and the average time to payment.

5. Promote integration: physicians, nurses, billing specialists and auditors should work collaboratively.

What is the impact of hospital auditing on the quality of care?

Beyond protecting finances, hospital auditing improves patient care. By checking that records are correct, the auditor helps make treatment safe, transparent and appropriate.

One example: if there is a discrepancy between what is in the medical record and the medication administered, this may indicate a care risk. In that case, auditing prevents not only a financial loss but also a possible medical error.

Which bodies and rules regulate hospital auditing?

In Brazil, hospital auditing is governed by the rules of the National Supplementary Health Agency (ANS) and the regulations of the Federal Council of Medicine (CFM) and the Federal Nursing Council (Cofen).

Health plan payers also have their own audit rules, which institutions must follow.

Fighting billing failures at scale with AI

Many institutions are already adopting artificial intelligence (AI) tools to optimize the hospital revenue cycle and reduce denials. AI can:

• read and interpret free-text clinical notes, such as physician progress notes;

• detect documentation gaps, such as missing justifications or contradictions;

• cross-check clinical data against billing rules;

• generate denial appeals automatically, based on clinical evidence;

• automate unified XML submission to payers.

Rivio is a healthtech that uses AI agents to manage the entire hospital revenue cycle. From audit to payment from health plans, we offer complete dashboards that let the hospital identify and prevent denials before they even happen. That means more security, more efficiency and greater predictability in hospital billing.

FAQ – frequently asked questions about hospital auditing

1. What is hospital auditing?

It is the process of reviewing claims, medical records and medical procedures to prevent errors and ensure services are billed correctly.

2. How are hospital auditing and hospital billing related?

Auditing checks whether what was recorded is correct, and billing turns those records into charges. Each depends on the other.

3. What are the types of hospital auditing?

Prospective (before care), concurrent (during) and retrospective (after discharge).

4. How does auditing help prevent denials?

It identifies errors and inconsistencies before the claim is submitted, reducing refusals by payers.

5. Who can work in hospital auditing?

Healthcare professionals, such as physicians and nurses, and administrative professionals trained in hospital management.

6. What does the hospital billing department do?

It checks medical forms, puts together claims, applies procedure codes and sends charges to health plans.

7. How do you do hospital billing correctly?

By following protocols, training teams and integrating auditing and billing.

8. What are the main causes of hospital claim denials?

Lack of clinical justification, coding errors, incomplete documentation and improper charges.

9. How can hospital billing be improved?

By investing in auditing, process standardization, technology and team training.

10. How can technology help with hospital auditing?

Software and AI speed up checks, reduce human error and automate billing processes.