How to Investigate Hospital Revenue Leakage

By Two Pillars & Co Advisory Group · Sources checked October 2026

What is revenue leakage?

Revenue leakage is the difference between what a hospital should have collected for the care it delivered and what it actually collected, excluding legitimate contractual adjustments and charity care. It is hard to see because each leak is small and spread across thousands of accounts: a missed charge here, a denied claim written off there, a patient balance never billed. Taken together, they can amount to a meaningful share of net revenue.

Leakage matters most when margins are thin. A hospital with a 2 percent operating margin that loses 1 percent of net patient revenue to leakage has lost half its margin. And unlike many cost initiatives, recovering revenue does not require reducing services.

Where does leakage occur?

Think of the revenue cycle as a chain with stages: patient access (scheduling, registration, insurance verification, authorization), pre-billing (charge capture, coding, documentation), claims (submission and clean claim rate), account resolution (payment posting, denials, appeals, patient collections) and financial management. The Healthcare Financial Management Association’s MAP Keys organize 29 indicators into five groups that mirror this chain: patient access, pre-billing, claims, account resolution and financial management.^[1]

Each indicator has a published definition with inclusions and exclusions, which allows consistent trending and benchmarking.^[1]

How do you size leakage?

Start with the indicators and trend them over at least a year. For example, the MAP Key for denial write-offs divides net dollars written off as denials by average monthly net patient service revenue, which converts a denial problem into a percentage of revenue.^[1] Charge lag is the average days between date of service and posting; long lag delays billing and increases the chance of missed charges. Days in discharged not final billed measures unbilled accounts relative to average daily gross revenue.^[1]

Then sample accounts. Pull a random sample of paid accounts and compare charges captured with the record of services delivered. Pull denied accounts and classify the reasons. The sample gives a rate that can be extrapolated, with a stated margin of error.

An invented example: a hospital with $250 million in net patient revenue finds denial write-offs equal to 1.6 percent of revenue ($4.0 million), of which a review suggests 40 percent were avoidable or appealable. The addressable leak is about $1.6 million a year. The numbers are illustrative only.

How do you find the causes?

Trace leaks to root causes. A rising denial rate may come from front-end authorization failures, coding errors, documentation gaps or payer behavior. The AHA reports that the Medicare Advantage plans issued nearly 50 million prior authorizations in 2023, up more than 40 percent since 2020, according to KFF, and that hospitals spent $26 billion in 2023 managing insurance claims, a 23 percent increase over the previous year, with 70 percent of denied claims eventually paid after multiple costly reviews.^[2] These figures come from a hospital trade association and the studies it cites, but they illustrate why denials are both a revenue and an administrative cost problem.

Look inside the organization too: registration accuracy, charge description master maintenance, coding turnaround, clinical documentation, and follow-up on aged accounts. Interview front-line staff; they often know where work-arounds hide errors.

How do you recover revenue safely?

Recovery must be compliant. The Office of Inspector General’s General Compliance Program Guidance notes that the Affordable Care Act requires entities to report and repay overpayments to Medicare and Medicaid by the later of 60 days after the date the overpayment was identified or the date any corresponding cost report is due, and that failing to do so can create False Claims Act liability.^[3] A revenue integrity program should therefore look for both underbilling and overbilling and have a process to return overpayments.

Prioritize fixes that remove the cause rather than chase individual accounts: front-end verification, charge capture edits, coding education, denial prevention and standard appeal workflows. Track results monthly with the same indicators. The interactive example below uses invented figures to show how leakage by stage can be sized.

Frequently asked questions

What to do next

1. Trend the MAP Key indicators for the last 12 months.
2. Sample paid and denied accounts to measure leakage rates.
3. Classify denials by root cause.
4. Fix upstream causes and keep a process for returning overpayments.