42 USC 1395nn — The Stark Law (Physician Self-Referral)

42 USC 1395nn, known as the Stark Law or physician self-referral law, prohibits a physician from referring Medicare patients for certain “designated health services” to an entity with which the physician — or an immediate family member — has a financial relationship, unless a specific exception applies. It also bars that entity from billing Medicare for the referred service. Crucially, the Stark Law is a strict liability civil statute: even an unintentional violation can create liability, because the government does not have to prove that the physician meant to break the law. That single feature is what makes it so different from every other statute in this area.

This page explains what the Stark Law prohibits, the key terms that define a violation, how its exceptions work, the civil penalties it carries, and how Stark issues are handled. It is a plain-English reference for physicians and health care entities trying to understand a self-referral problem in California. To see how we defend health care matters that involve Stark questions, visit our federal health care fraud defense page.

Summary of the Statute

Codified at 42 USC 1395nn and originating in Section 1877 of the Social Security Act, the Stark Law was first enacted in 1989 and expanded in the early 1990s. It is named for Congressman Pete Stark, who championed it, and the Centers for Medicare and Medicaid Services (CMS) administer it through a detailed and frequently updated set of regulations.

The core idea is straightforward: a physician’s medical judgment should not be influenced by personal financial gain. When a doctor stands to profit from sending a patient for a test, procedure, or service, the worry is that the referral may be driven by the doctor’s interest rather than the patient’s need. The statute therefore prohibits two linked acts. First, a physician may not refer a Medicare patient for a designated health service to an entity with which the physician (or an immediate family member) has a financial relationship. Second, that entity may not submit a claim for the improperly referred service — and if a claim was paid, the money must be refunded.

What sets the Stark Law apart from the criminal fraud statutes is its strict liability nature. Where the Anti-Kickback Statute requires proof that a defendant acted knowingly and willfully, Stark liability can attach to a financial arrangement that simply fails to meet an exception — regardless of intent, and regardless of whether anyone meant to do anything wrong. A purely technical, paperwork-level failure can be enough.

Key Terms That Define a Violation

Three defined terms do most of the work in a Stark analysis, and understanding them is the key to understanding the law’s reach.

Designated Health Services (DHS)

The Stark Law applies only to a defined list of “designated health services.” These include clinical laboratory services; physical therapy, occupational therapy, and outpatient speech-language pathology; radiology and certain imaging such as MRI, CT, and ultrasound; radiation therapy; durable medical equipment and supplies; parenteral and enteral nutrients; prosthetics and orthotics; home health services; outpatient prescription drugs; and inpatient and outpatient hospital services. If a referral is not for a DHS, the Stark Law does not apply.

Financial Relationship

A prohibited financial relationship can take two forms: an ownership or investment interest in the entity, or a compensation arrangement with it. Both direct and indirect relationships count. Because so many ordinary business structures — group practices, equipment leases, medical directorships, office subleases — create financial relationships, the law’s reach is extremely wide, and arrangements that feel entirely routine can trigger it.

Referral

A “referral” is the physician’s request for the designated health service. Where the referral is for a DHS payable by Medicare and a financial relationship exists, the prohibition is triggered automatically unless an exception fits — there is no inquiry into why the physician made the referral.

Stark Law Exceptions

Because the prohibition is so broad that it would otherwise sweep in countless legitimate arrangements, Congress and CMS created a long list of exceptions for arrangements that pose little risk of abuse. Common examples include bona fide employment relationships, properly structured space and equipment rentals, personal-service arrangements, in-office ancillary services, and certain physician recruitment arrangements.

Here lies a critical difference from the Anti-Kickback Statute, and it is one providers frequently misunderstand. AKS “safe harbors” are voluntary — falling outside one is not automatically illegal, because the AKS still requires proof of intent. Stark “exceptions,” by contrast, are mandatory: because Stark is strict liability, an arrangement must fit squarely within an exception, satisfying every single element, or the referral is simply prohibited. There is no “we meant well” defense. This is why precise structuring and meticulous documentation of physician arrangements is so important, and why even a technical lapse — a missing signature, an expired written agreement, rent that drifts from fair market value — can create exposure.

Penalties Under 42 USC 1395nn

The Stark Law is civil, but its penalties are severe — and because each improperly billed service counts separately, they can climb into the millions over time. Base statutory amounts are adjusted upward for inflation each year, so the figures below are approximate current ceilings.

The most serious exposure, though, is often indirect. A claim submitted in violation of the Stark Law can also become a false claim, triggering treble damages and per-claim penalties under the False Claims Act. And because providers are required to return identified overpayments within 60 days, keeping money from a Stark-tainted claim past that deadline can open a second front of liability as a “reverse false claim.” A relatively modest Stark problem can, through these mechanisms, become a major financial case.

Related Federal Statutes

• 42 USC 1320a-7b (Anti-Kickback Statute) — the criminal, intent-based companion that frequently overlaps with Stark issues.
• 31 USC 3729 (False Claims Act) — turns Stark-tainted claims into false claims with treble damages.
• 18 USC 1347 (health care fraud) — the criminal fraud statute that may be charged where self-referral is part of a larger scheme to defraud.

How Stark Law Issues Are Addressed

Because Stark is strict liability, the defense rarely turns on intent — arguing that a violation was accidental does not, by itself, avoid liability. Instead, the analysis focuses on demonstrating that an arrangement actually met an exception, element by element, which is the cleanest path to no liability at all. Where a violation has occurred, providers can limit exposure through the CMS Self-Referral Disclosure Protocol, a mechanism for self-reporting and resolving Stark issues at a reduced amount.

Other strategies dispute the government’s characterization of a “financial relationship,” contest the number of services actually affected, or challenge whether a given service even qualifies as a designated health service. Because the financial consequences flow from the number of tainted claims, narrowing that count can substantially reduce exposure. For the practical distinction physicians most often ask about, see our explainer comparing the Anti-Kickback Statute and Stark Law. The right approach depends on the specific arrangement and how it was documented.

Dealing With a Stark Law Issue? Contact Us

A Stark Law problem can quickly grow into False Claims Act and even criminal exposure if it is not handled carefully and early. Whether you are responding to an audit, a CMS inquiry, or a broader fraud investigation, experienced counsel can help you choose between defending an exception, self-disclosing, and negotiating a resolution. KN Law Firm, APLC handles health care fraud matters in the U.S. District Court for the Central District of California and before the Ninth Circuit. Call (888) 950-0011 for a free, confidential consultation with attorney Chris Nalchadjian, available 24/7 in English and Spanish.