We all know that the Stark law prohibits doctors from referring lab tests to labs they have an ownership in. How about the daily occurence of a pathologist owning his ab business, and every hour referring something to it - IHC stains on a breast cancer case, special stains for unexpected possible organisms, and so on. Why don't these orders "to a lab the referring doctor has an ownership interest in" trigger Stark?
It may seem like a puzzle, and the answers are buried in Stark law definitions and details.
NOTE: The essay below is AI-generated, and should NEVER be construed as actual legal opinion or advice. Take it as the current ability of AI to understand a situation and write about it. For legal answers to actual situations, get a lawyer.
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The Stain Order That Wasn’t a Stark Referral
A case study in pathology, ownership, and the meaning of “referral”
Dr. Dan Michaels had barely settled into Oak Street Pathology Group when a colleague brought him a question from the golf course.
“Everyone knows Stark prohibits doctors from sending lab work to a lab they own,” the colleague said. “So how can we own this laboratory and order stains on our own cases all day long? We do the work, bill Medicare, and Medicare pays. Isn’t that exactly what the law was meant to stop?”
The example was concrete. Michaels had received a breast biopsy for consultation. After examining the tissue, he ordered additional levels, special stains, and immunostains. Oak Street’s laboratory performed the work. The group billed Medicare, which paid the claims. Seven pathologists owned the practice and shared equity in the lab.
The apparent contradiction seemed hard to escape:
- Stark generally prohibits a physician from referring Medicare patients for designated health services to an entity with which the physician has a financial relationship, unless an exception applies.
- Clinical laboratory services are designated health services, and pathologists commonly own or invest in the laboratories where pathology work is performed.
- Pathologists routinely order additional work on referred specimens, and their laboratories bill for it.
Michaels tried Google. The broad summaries he found repeated the general prohibition but did not explain the pathology workflow.
His nephew Brad, a law student writing an honors thesis on physician self-referral, took the question to two health-law professors. Two months later, Brad returned with a short answer and a long regulatory history.
The answer was in the word referral. The Stark statute contains a specific rule under which certain orders by a pathologist do not count as referrals at all. That is different from saying the pathologist’s ownership interest is irrelevant, and it's also different from relying on the familiar in-office ancillary services exception.
First, sharpen the premise
Stark does not simply say, “A physician may never order a laboratory test from a lab the physician owns.” It generally prohibits a physician from making a referral for a Medicare-covered designated health service to an entity with which the physician or an immediate family member has a financial relationship, unless a statutory or regulatory exception applies. Ownership can create the financial relationship; the prohibited referral is the other essential part of the analysis.
The law defines clinical laboratory services broadly enough to include pathological examinations. Thus, the issue cannot be dismissed by saying that pathology stains are outside Stark. They may be designated health services. The question is whether the pathologist’s order is a “referral” within the law’s definition.
The statute answers that question for a defined class of specialist services. Under Social Security Act § 1877(h)(5)(C), a pathologist’s request for clinical diagnostic laboratory tests and pathological examination services is not a referral when the services are furnished by or under the supervision of the pathologist pursuant to a consultation requested by another physician. The statute names parallel provisions for diagnostic radiologists and radiation oncologists. www.govinfo.gov
The implementing regulation is 42 C.F.R. § 411.351, definition of “Referral,” paragraph (2). In the current text, the request must result from a consultation initiated by another physician; the consultation may be requested from a particular pathologist or from an entity with which the pathologist is affiliated. The tests must be furnished by or under the pathologist’s supervision, or under the supervision of a pathologist in the same group practice. www.law.cornell.edu
So, in the ordinary referred-specimen case, the sequence is:
Treating physician requests pathology consultation → pathologist evaluates the case → pathologist orders stains or other pathology work needed for the examination → the pathologist or another pathologist in the group supervises the services.
When those conditions are met, the pathologist’s order is excluded from the definition of a Stark referral. The fact that Oak Street’s laboratory performs and bills for the stains does not, by itself, turn that excluded order into a prohibited referral.
“Consultation” is a legal term here
The rule does not require a pathologist to see the patient or conduct a conventional bedside consultation. For Stark purposes, § 411.351 defines a consultation as a professional service in which another physician requests the pathologist’s opinion or advice about a specific medical problem; the request and need are documented in the record; and the pathologist prepares a written report for the requesting physician. www.law.cornell.edu
That definition was shaped in rulemaking partly because the ordinary Medicare consultation model fit pathology poorly. A pathologist usually evaluates a specimen rather than taking a patient history or performing a physical examination. CMS ultimately said that the Stark consultation definition does not require either step. It is a Stark-specific definition and does not change Medicare coverage or payment rules for services billed as consultations. www.federalregister.gov
The original physician’s role matters. CMS described the protected specialist as responding to a consultation while the requesting physician remains involved in deciding how to proceed with the patient’s care. If the specialist instead takes over care, or if a patient simply walks in without a consultation initiated by another physician, the special definition may not apply. The pathologist’s subsequent orders then need to be analyzed under the ordinary Stark rules and any applicable exception. www.govinfo.gov
How the rule reached Oak Street
The statute came first
The pathologist language is not a CMS-created loophole. Congress placed the specialist provision in the Stark statute. The 1995 rulemaking was the first major regulatory step that incorporated the clinical-laboratory provisions into 42 C.F.R. § 411.351. Later statutory amendments expanded the corresponding language for radiology and radiation oncology, and CMS incorporated those changes through subsequent rulemaking. www.federalregister.gov
The 1995 final rule confronted the ownership problem directly
In the 1995 final rule, commenters asked CMS about a pathologist who provided professional services to one laboratory but sent specimens to a second laboratory in which the pathologist had a financial interest. They also asked whether the rule should protect a pathologist who recommended additional laboratory work to the attending physician.
CMS drew a practical line. If the pathologist performed or supervised the laboratory testing at the second lab, the pathologist’s request was not a referral under the statutory provision. If the pathologist sent the work to a lab in which the pathologist had a financial interest but did not perform or supervise the services, CMS said the referral could be prohibited unless another exception applied. CMS separately said that a pathologist’s recommendation for more testing was not itself a referral: the attending physician ultimately decides whether the testing is needed and where to order it. www.govinfo.gov
The rulemaking therefore addressed the kind of two-laboratory arrangement that can look superficially like Oak Street’s. The deciding fact was not simply that the pathologist owned part of a lab. It was whether the request arose from another physician’s consultation and whether the pathologist performed or supervised the service as the law requires.
The 2001 final rule defined the consultation boundary
CMS proposed a broader Stark framework in 1998 and received comments that the consultation concept was unclear. Commenters questioned whether a consultant had to take a history and examine the patient, and how to distinguish consultation from a transfer of care.
In the 2001 Phase I final rule, CMS adopted the three central criteria now reflected in § 411.351: another physician requests an opinion or advice about a specific medical problem; the request and need are documented; and the consultant provides a written report. CMS expressly rejected a patient-history or physical-examination requirement for Stark consultations, recognizing that pathologists rarely see patients. www.federalregister.gov
CMS also emphasized that the statutory protection was narrow: it applied to the named specialists and named categories of services. It did not extend the carve-out to all physicians who order diagnostic tests.
The 2007 rule clarified group supervision and walk-in cases
The 2007 Phase III final rule clarified that qualifying services could be supervised by another pathologist in the same group practice. It also rejected a request to extend the carve-out to walk-in patients. CMS reasoned that the consultation provision assumes another physician has already determined that the patient likely needs the specialist’s services. That rationale is absent when the patient initiates the encounter. www.govinfo.gov
CMS further confirmed that the consultation exclusion can cover technical components ordered by hospital-based pathologists when the other requirements are met. But it declined to extend the exclusion to every physician employed by the same hospital. The agency pointed instead to other Stark exceptions, such as the bona fide employment exception, where appropriate. www.govinfo.gov
Why this is not just the in-office ancillary exception?
The pathologist provision and the in-office ancillary services exception can lead to similar practical outcomes, but they work differently.
The pathologist rule is in the definition of “referral.” A qualifying request is not a referral under Stark in the first place. The in-office ancillary services exception, at § 411.355(b), assumes there is a referral and protects it if detailed requirements are met, including requirements concerning who furnishes or supervises the service, location, and billing.
CMS also distinguished the supervision standards. The pathologist provision requires “supervision” as defined by applicable Medicare coverage and payment requirements or relevant health-and-safety standards. The in-office ancillary exception has its own supervision requirements. In other words, one cannot assume the pathologist carve-out is merely an application of the ordinary in-office exception, or that every arrangement qualifying under one automatically qualifies under the other. www.govinfo.gov
What Brad’s memo says about Dr. Michaels
On the facts as presented, Michaels receives a specimen for pathology consultation from another physician. He determines that additional stains are needed to complete the pathologic examination. Oak Street’s laboratory performs them under his supervision, or under the supervision of another pathologist in the same group. The group bills Medicare for the services.
The pathologist’s request fits the statutory and regulatory exclusion from “referral,” assuming the consultation and supervision conditions are documented and satisfied. The answer is not that Stark has no application to pathology, nor that ownership is irrelevant. The answer is that the qualifying pathologist order is specifically excluded from the Stark definition of a referral.
The boundary cases remain important. A walk-in patient, testing outside the pathology consultation, an order sent to a lab without the required supervision, or a referring physician’s own financial relationship with the lab may change the analysis. The pathologist provision also does not resolve separate questions under the Anti-Kickback Statute, state self-referral laws, Medicare billing rules, or payer contracts.
Sidebar: Is the carve-out limited to “diagnostic” tests?
The statute uses the phrase “clinical diagnostic laboratory tests and pathological examination services,” and the regulation refers to clinical diagnostic laboratory tests and pathological examination services. But the provision is not written as a special exemption only for conventional histology, special stains, or immunostains, nor does it separately distinguish diagnostic tests from prognostic tests or genomic profiling.
The relevant categories are the services named in the statute and regulation. The Stark regulation defines clinical laboratory services to include pathological examinations and ties the category to the applicable CPT/HCPCS code list. Therefore, a prognostic or comprehensive genomic profiling service is not automatically in or out merely because it is called “prognostic” or “CGP.” The precise service and code, whether it is a designated health service, and whether it is part of the pathologist’s qualifying consultation must be examined. The label alone does not resolve the Stark question. www.law.cornell.edu
A cold corner of Stark law
This is a technically important but relatively quiet corner of Stark. The statutory carve-out dates to the law’s early history; CMS incorporated it into regulation in 1995, clarified “consultation” in 2001, and addressed group supervision and edge cases in 2007. The rule has not suddenly appeared to excuse a new business model. It reflects a long-standing distinction between a physician steering a patient to a financially connected lab and a pathologist completing the examination requested by the treating physician.
For Dr. Michaels, the golf-course puzzle is solved: the stains are not “referrals” under Stark when the case arises from a qualifying consultation and the pathologist or a pathologist in the group furnishes or supervises the work as the rule requires.
Primary sources
- Social Security Act § 1877, 42 U.S.C. § 1395nn — statutory referral definition and specialist provision.
- 42 C.F.R. § 411.351, Definitions — current definitions of “clinical laboratory services,” “consultation,” and “referral.”
- 42 C.F.R. § 411.355(b), In-office ancillary services — separate in-office ancillary services exception.
- 1995 final rule, 60 Fed. Reg. 41914 (Aug. 14, 1995) — initial regulatory incorporation of the clinical laboratory referral rules and CMS responses to comments on pathology arrangements.
- 1998 proposed rule, 63 Fed. Reg. 1659 (Jan. 9, 1998) — proposed Stark framework and discussion of consultations and supervision.
- 2001 Phase I final rule, 66 Fed. Reg. 856 (Jan. 4, 2001) — final consultation definition and responses to comments.
- 2004 Phase II interim final rule, 69 Fed. Reg. 16054 (Mar. 26, 2004) — next stage of Stark implementation.
- 2007 Phase III final rule, 72 Fed. Reg. 51012 (Sept. 5, 2007) — group-practice supervision, walk-in patients, and hospital-based technical components.







