Center for Advanced Study & Research on Innovation Policy


CASRIP Newsletter - Autumn/Winter 2007, Volume 14, Issue 1

LabCorp v. Metabolite: Can one Patent a Basic Scientific Relationship?

By Christopher L. Kuyper

 I.          Introduction

The United States Supreme Court recently placed the future of diagnostic method patents into question.  In Lab. Corp. of Am. Holdings v. Metabolite Labs., Inc.,[1] the controversial patent pertained to a diagnostic method for correlating elevated levels of homocysteine, an amino acid, with a patient’s deficiency of two B vitamins, cobalamin and folate.  The issue before the Court was whether the patent protected a monopoly on a basic scientific relationship.  The United States District Court for the District of Colorado ruled the patent valid.[2]  The United States Court of Appeals for the Federal Circuit affirmed.[3]  The Supreme Court granted certiorari,[4] but later dismissed the writ as “improvidently granted.”[5]  Justice Breyer wrote a dissent, joined by Justices Souter and Stevens, expressing disagreement with the dismissal of the case.[6]  In addition, the dissent argued that the patent would be invalid because the claimed scientific relationship was an unpatentable “natural phenomenon.”[7] 

This case has particular relevance to the medical community because under current law, physicians directly infringe Metabolite’s patent rights each time a total homocysteine test is used to correlate a patient’s deficiency in cobalamin or folate.[8]  In light of the Federal Circuit’s ruling, physicians will now have to take extra care in determining whether the use of diagnostic test data infringes a patent.  Because the future is uncertain for patents that claim vitally important scientific relationships, such as this one, potential investors may now be wary of companies that develop diagnostic methods.  Although the future is uncertain, until the Supreme Court states otherwise, claims that protect basic scientific relationships are still patentable. 

 II.        LabCorp’s Indirect Infringement and Partial Breach of Contract

In the United States District Court for the District of Colorado, Metabolite sued LabCorp for infringement of U.S. Patent No. 4,940,658 (“the ‘658 patent”) and for breach of contract.[9]  In the ‘658 patent, claim 13, the primary claim at issue, covered a method for detecting deficiencies of two vitamins, cobalamin (vitamin B12) and folate (folic acid).  Low amounts of these B vitamins can cause serious illnesses; however, if the deficiency is caught early, supplements can be used for treatment.  Problems from these deficiencies arise because the minerals contribute in metabolizing homocysteine, an amino acid.  By assaying for a total amount of homocysteine, simple tests can be used to correlate elevated levels of the amino acid to deficient levels of either cobalamin or folate.  Physicians routinely use these tests to diagnose and treat related illnesses.

In 1991, LabCorp, a clinical laboratory, sublicensed the ‘658 patent from Metabolite and began to promote use of the homocysteine tests to the medical community.[10]  The agreement stipulated that LabCorp could terminate the sublicense if a more appropriate and cost effective alternative, which did not infringe the ‘658 patent, became available.[11]  In 1998, LabCorp stopped using the Metabolite technology and switched to a total homocysteine assay provided by Abbott Laboratories (“the Abbott test”).[12]  After LabCorp discontinued royalty payments, Metabolite sued and a jury found the company liable for indirect infringement and partial breach of contract awarding $1,019,365 and $3,652,724 for each action, respectively.[13]  Subsequently, the district court denied LabCorp’s motion for judgment as a matter of law, enjoined the company from using total homocysteine assays, and doubled the infringement award to $2,038,730 due to the jury’s finding of willful infringement.[14]  


III.       Current Scope of Claim 13 in the `658 Patent

On appeal, the Federal Circuit affirmed the district court’s decision.[15]  In its analysis, the Federal Circuit reviewed the construction of claim 13,[16] which on its face is seemingly broad, and reads as follows:

13.        A method for detecting a deficiency of cobalamin or folate in warm-blooded animals comprising the steps of: 

assaying a body fluid for an elevated level of total homocysteine; and

correlating an elevated level of total homocysteine in said body fluid with a deficiency of cobalamin or folate.[17]

Supporting a broad construction, the Federal Circuit agreed with the district court’s conclusion that “correlate” means the dictionary definition, ‘‘to establish a mutual or reciprocal relationship between.”[18]  In this context, a mutual relationship results when homocysteine levels are elevated, and a reciprocal relationship is established when increased levels are absent.  LabCorp contended that the claim should only cover a mutual relationship because 20 percent of the assays correlated elevated levels of homocysteine to diagnose a B vitamin deficiency.[19]  The other 80 percent of the tests reported a reciprocal relationship and did not require the act of “correlation.”[20]  Nonetheless, the majority affirmed the district court’s finding that claim 13 covered both mutual and reciprocal relationships.[21]  Dissenting in part, Circuit Judge Schall agreed with LabCorp that claim 13 should not have been construed to cover a reciprocal relationship stating, “[i]f the patient’s homocysteine levels are not ‘elevated,’ by the plain language of the claim, there is no ‘correlating’ to be done.”[22]   

As a result of the broad claim construction, the Federal Circuit affirmed LabCorp’s indirect infringement of the ‘658 patent by actively inducing direct infringement by physicians who used the total homocysteine tests.[23]  Direct infringement occurrs from a physician’s simple mental exercise of reading a test result to determine whether a patient has deficiencies of cobalamin or folic acid.  This restriction on the medical community stimulated the primary issue before the Court and was the focus of the dissent written by Justice Breyer.


IV.       Justice Breyer’s Dissent

The Court originally granted certiorari to decide “[w]hether a method patent … directing a party simply to ‘correlate’ test results can validly claim a monopoly over a basic scientific relationship … such that any doctor necessarily infringes the patent merely by thinking about the relationship after looking at a test result.”[24]  The Court did not rule on the question, however, and dismissed the writ as improvidently granted.[25]  

Justice Breyer, who was joined by Justices Stevens and Souter, dissented to the dismissal and further expressed a belief that the claim would be invalid under the “natural phenomenon” doctrine.[26]  While the majority did not comment, the dissent suggested that the reason for the dismissal was procedural because LabCorp never directly argued that the patent covered unpatentable subject matter under 35 U.S.C. §101.  Accordingly, the Court likely wanted to see a better record of this issue from the lower courts.  The dissent argued against the dismissal by highlighting LabCorp’s argument to the Federal Circuit that construction of claim 13 was “vague,” allowed for patent protection of a “scientific correlation,” and improperly claimed a “monopoly over a basic scientific fact.”[27]  Furthermore, the dissent pointed out that the court granted certiorari even though the Solicitor General advised against taking the case mainly because no decision had been made with regard to §101.[28]  Also, in the dissent’s view, there was no appearance of unfair gamesmanship on the part of LabCorp by failing to cite §101.[29]  Last, the dissent contended that the medical community and patients would have benefited from a decision.

Even though patentability under §101 was not directly argued by LabCorp in the lower courts, the dissent believed that the issue was implied and proposed the following question, “does the law permit such protection or does claim 13, in the circumstances, amount to an invalid effort to patent a ‘phenomenon of nature’?” [30]  After conceding that the scope of the natural phenomenon doctrine can be unclear in certain cases, the dissent argued that claim 13 was clearly a “natural phenomenon” even under a narrow interpretation of the doctrine.  The dissent was not convinced by Metabolite’s contention that the correlation, standing alone, could literally be a “natural phenomenon,” but claim 13 packaged the correlation into a process for detecting the vitamin deficiency.  Thus, the method claim was an “application of a law of nature.”[31] The dissent argued that even if the claim satisfied “general definitions of process patentability . . . it still fails the one at issue here:  the requirement that it not amount to a simple natural correlation, i.e., a ‘natural phenomenon.’”[32] 


V.        Future of Diagnostic Method Patents

The dissent seemingly provides a convenient template for the Court to decide the merits of a future claim similar to the one at issue in this case.  With three out of nine justices dissenting, there is a plausible notion that given a case without procedural problems, the current scope of patentability for diagnostic methods could change drastically.  Such a shift would have far reaching repercussions for both the medical community and companies that supply those physicians with the means and knowledge to use vitally important, biological relationships in diagnosis and treatment.  In a persuasive argument for the medical community, the dissent discussed several disadvantages of patents similar to the ‘658 patent: physicians would be restricted when making the best judgments about a patient’s condition, would waste time and energy entering into license agreements, and would have to perform patent searches before using any test results.[33]  Such burdens would likely raise healthcare costs, as well.[34] 

The potential realities presented by the dissent, however, only addressed the effect on physicians.  The implications are more complicated considering the current trend towards personalized medicine.  More personalized care will require an abundance of assays to determine specific biological information about each patient.  For example, relationships such as those elucidated by the total homocysteine test are imperative when providing effective healthcare.  To the contrary, if diagnostic method patents are invalidated, then companies and investors may no longer see an incentive to seek out these relationships.  Arguably, new developments may stall. 

While the dissent shows one potential view of the Court, diagnostic method patents remain valid.  The patent and medical communities can now wait anxiously for an opportunity in which the Court may redefine the scope of patentability regarding diagnostic method patents.  

Dr. Kuyper is a J.D. candidate (class of 2009) at the University of Washington School of Law.

[1] Lab. Corp. of Am. Holdings v. Metabolite Labs., Inc., 126 S. Ct. 2921 (2006) (mem) (Breyer, J., dissenting) (dissenting from majority’s decision to dismiss writ of certiorari).

[2] Metabolite Labs., Inc. v. Lab. Corp. of Am. Holdings, No. 99-CV-870, 2001 WL 34778749, at *1 (D. Colo. Dec. 3, 2001).

[3] Metabolite Labs., Inc. v. Lab. Corp. of Am. Holdings, 370 F.3d 1354 (Fed. Cir. 2004). 

[4] Lab. Corp. of Am. Holdings v. Metabolite Labs., Inc., 126 S. Ct. 543 (2005) (mem).

[5] Lab. Corp., 126 S. Ct. at 2921.

[6] Lab. Corp., 126 S. Ct. at 2921 (Breyer, J., dissenting).

[7] Id. at 2927.

[8] Metabolite Labs., 370 F.3d at 1358.

[9] Metabolite Labs., 2001 WL 34778749, at *1.

[10] Lab. Corp., 126 S. Ct. at 2923 (Breyer, J., dissenting).

[11] Id.

[12] Id.

[13] Metabolite Labs., 2001 WL 34778749, at *1.

[14] Metabolite Labs., 370 F.3d at 1358.

[15] Id. 

[16] Id. at 1359-64.

[17] Id. at 1358 (quoting U.S. Patent No. 4,940,658 (filed Nov. 20, 1986)).

[18] Id. at 1363.

[19] Id.

[20] Id.

[21] Id. at 1364.

[22] Id. at 1374 (Schall, J., dissenting).

[23] Id. at 1364-65.

[24] Lab. Corp., 126 S. Ct. at 2924 (Breyer, J., dissenting).

[25] Lab. Corp., 126 S. Ct. at 2921.

[26] Id.

[27] Id. at 2925. 

[28] Id. at 2926.

[29] Id.

[30] Id.  

[31] Id. at 2927.  

[32] Id. at 2928 (citing Parker v. Flook, 437 U.S. 584, 589 (1978); Diamond v. Diehr, 450 U.S. 175, 184-185 (1981)).

[33] Id. at 2928.

[34] Id. at 2929.


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