Patient Leakage

What is patient leakage?

Patient leakage happens when a patient attached to a health system, often through an employed or affiliated primary care physician, gets specialist visits, imaging, surgery or other services from an unaffiliated provider. The revenue and the clinical record for that care leave the system.

The opposite measure is often called referral retention or keepage: the share of care that stays in network. Leakage can be measured for a whole system, a service line such as orthopedics, or a single referring physician.

Not all leakage is avoidable. A system may not offer the service, the patient's insurer may not include the system in its network, or the patient may simply prefer another provider.

How patient leakage is measured

A typical analysis follows these steps:

• Define the population: patients attributed to the system through primary care visits, health plan attribution or an accountable care organization roster.
• Collect claims for those patients across all providers, not only the system's own billing records.
• Classify each service as in network or out of network by matching rendering and facility identifiers such as the National Provider Identifier (NPI) and the CMS Certification Number (CCN).
• Calculate leakage by service line, referring physician and destination provider, weighted by visits or estimated spending.

Why patient leakage matters

For health systems, leakage affects revenue, care coordination and performance under value-based contracts. When a system carries financial risk for a population, care delivered elsewhere still counts against its cost targets but is harder to manage.

Physician liaisons and strategy teams use leakage reports to find referring physicians who send patients elsewhere and the reasons behind it, such as long wait times, scheduling friction or missing services. Investors and consultants use leakage estimates to size the opportunity from adding a service line or acquiring a practice.

Limits on reducing leakage

Health systems cannot simply require all referrals to stay in house. Patients generally keep the right to choose their providers, and federal fraud and abuse laws restrict paying for or rewarding referrals.

Stark Law regulations allow an employer to direct a physician's referrals to particular providers only under specific conditions, and the direction cannot apply when the patient prefers a different provider, the patient's insurer determines the provider, or the physician judges the direction is not in the patient's best interest. Measurement has gaps too: claims from a single payer or from Medicare alone show only part of a patient's care.