The Doctrine of Claim Differentiation: Who Got It Right in Retractable Technologies?

By Eric Guttag
July 13, 2011

Chief Judge Randall Rader of the Federal Circuit

One of the canons in the perplexing world of patent claim construction is the doctrine of claim differentiation.  As stated in the seminal 2005 claim construction case of Phillips v. AWH Corp., this doctrine holds that “the presence of a dependent claim that adds a particular limitation gives rise to a presumption that the limitation in question is not present in the independent claim.”  But the recent case of Retractable Technologies, Inc. v. Becton, Dickinson & Co. saw a split panel of the Federal Circuit take very divergent views on whether the “presumption” created by this doctrine was rebutted by other facts.  In my opinion, dissenting Chief Judge Rader’s  view is correct.  Rader explained that the “strong presumption” created by this doctrine was not rebutted by the facts in this case.  Conversely, the view of Judge Lourie (writing for the panel majority that included Judge Plager) was that this “implication [was] not a strong one” and won’t hold up under careful scrutiny.

In Retractable Technologies, the claimed invention related to retractable syringes, i.e., medical syringes that feature a needle that retracts into the syringe body after the syringe is used.  Independent Claim 1 of U.S. Pat. No. 7,351,224 (the “’224 patent”) recited a “syringe comprising a hollow body,” while independent Claim 43 of the ’224 patent recited a syringe assembly which comprised a “hollow syringe body.”  Dependent Claim 14 of the ’224 patent recited “[t]he syringe of claim 1 comprising a one-piece barrel,” while dependent Claim 57 recited “[t]he syringe assembly of claim 43 wherein the body comprises a one-piece barrel.”  In other words, both dependent Claim 14, as well as dependent Claim 57, were limited to a “one-piece” structure for the “hollow [syringe] body.”  And under the doctrine of claim differentiation, that would raise the “strong presumption” that the “hollow [syringe] body” of independent Claims 1 and 43 need not be a “one-piece” structure, but could also be a “multi-piece” structure.

Whether the term “body” encompassed “multi-piece” structures became the crux of the claim construction issues in Retractable Technologies.  The District Court for Eastern Texas, apparently applying the doctrine of claim differentiation, construed independent Claims 1 and 43 to cover a “body” which might be a “multi-piece” structure.  Accordingly, the District Court denied post-trial motions by the alleged infringer (Becton Dickinson or “BD”) to overturn the jury verdict that BD infringed these Claims of the ‘224 patent.

Judge Lourie (writing for the panel majority) reversed the District Court, ruling that the term “body” was limited to a “one-piece” structure in light of the ‘224 patent specification (as well as the specifications of two other patents that were asserted to be infringed).  In fact, Judge Lourie’s opinion barely acknowledges that the doctrine of claim differentiation was in play (only stating that BD argued that “claim differentiation does not apply in light of the written description’s limiting statement [in the ‘224 patent specification]”).  While noting that the some of the dependent Claims of the ‘224 patent limited the “body” to a “one-piece body,” Judge Lourie also observed that “none of the claims expressly recite a body that contains multiple pieces.”  Accordingly, while the claims could “be read to imply that the body’ [wasn’t] limited to a one-piece structure, that implication [wasn’t] a strong one.”

Instead, Judge Lourie reached for another canon of claim construction from the Phillips case, namely “the claim language must always be read in view of the written description” in the patent specification.  In this regard, Judge Lourie noted the following facts from the ‘224 patent specification (as well as the other patent specifications) that suggested the term “body” was limited to one-piece structures:  (1) describing the prior art as “fail[ing] to recognize” that a retractable syringe could be molded as a one piece outer body; (2) the Summary of the Invention section stated that the syringe “features a one piece hollow body”; and (3) “each syringe embodiment” was described as “contain[ing] a one-piece.” In contrast, the “[patent] specifications [including that of the ‘224 patent] do not disclose a body that consists of multiple pieces or indicate that the body is anything other than a one-piece body.”  Accordingly, “while the claims leave open the possibility that the recited ‘body’ may encompass a syringe body composed of more than one piece, the specifications tell us otherwise.”

In Judge Plager’s concurring opinion, the doctrine of claim differentiation is conspicuous by the absence of any mention of this claim construction canon.  Instead, Judge Plager focused almost exclusively on the alleged “curse of indefinite and ambiguous claims, divorced from the written description, that we regularly are asked to construe, and the need for more stringent rules to control the curse.”  In other words, Judge Plager viewed the claim construction issue in Retractable Technologies as being one of “written description” under 35 U.S.C. § 112, first paragraph, and possibly (though ambiguously stated) of “indefiniteness” under 35 U.S.C. § 112, second paragraph.

But what about the “presumption” under the doctrine of claim differentiation against importing limitations into the independent claim(s) which are recited in the dependent claim(s) (as Chief Judge Rader figuratively “screamed” in his blistering dissent)? Instead, Chief Judge Rader referred to another claim construction canon from the Phillips case:  the claims themselves, not the written description portion of the specification, define the claimed invention.  In referring to yet another claim construction canon from Phillips (claim language is to be given its ordinary and customary meaning), Chief Judge Rader observed that “neither party contends that ‘body’ has a special, technical meaning in th[is] field of art.”  That meant that the claim construction required “little more than the application of the widely accepted meaning of commonly understood words,” i.e., did not mean that the term “body” was limited to one-piece structures.

Instead, and firmly relying upon the doctrine of claim differentiation, Chief Judge Rader pointed to the claim language as evidencing that the term “body” was not limited to one-piece structures.  In fact, Chief Judge Rader observed that the “presumption” created by this doctrine is “especially strong when the limitation in dispute is the only meaningful difference between an independent and dependent claim, and one party is urging that the limitation in the dependent claim should be read into the independent claim” (citing the 2003 Federal Circuit decision in SunRace Roots Enterprise Co. v. SRAM Corp.)

While Chief Judge Rader agreed that the claims “must be read in light of the specification,” he further stated that nothing in the patent specifications (including that of the ‘224 patent) rebutted the “strong presumption” created by the claim language that “body” does not contain a one-piece structural limitation.  In sum, construing the claim term “body” in these patents (including the ‘224 patent) as being limited to a one-piece structure was viewed by him as “contrary to the ordinary and customary meaning of the word ‘body,’ violat[ing] the doctrine of claim differentiation, and lack[ing] support in the patents at issue.”

Admittedly, the patent applicant in Retractable Technologies might have avoided this claim construction conundrum by specifically exemplifying multi-piece “body” embodiments in the patent specifications, and especially by avoiding such limiting references in the Summary of the Invention section (which unfortunately has created another faulty “presumption” in the minds of some judges that the claimed invention is somehow limited by what is described in this section).  The patent applicant in Retractable Technologies may also have dangerously flirted with a potential lack of “enablement” issue under 35 U.S.C. § 112, first paragraph, in not specifically exemplifying multi-piece “body” embodiments.  But Chief Judge Rader is on solid footing in arguing that the “presumption” created by the doctrine of claim differentiation mandates strongly against reading limitations of the dependent claims into the independent claims, and wasn’t effectively rebutted with respect to the term “body.” For the panel majority (through Judge Lourie) to say that this “implication is not a strong one” in Retractable Technologies defies the facts, logic, and most significantly, binding Federal Circuit precedent.

© 2011 Eric W. Guttag.

The Author

Eric Guttag

Eric Guttag  
Mr. Guttag has over 38 years of corporate and private intellectual property law experience on patent, trademark, copyright, trade secret and unfair competition matters, computer and Internet law, including patent application drafting, prosecution, and patentability studies; infringement and validity studies; international patent prosecution; patent and know-how licensing; consulting, confidentiality, clinical study and research agreements; trademark searches and opinions; trademark registration and prosecution; trademark freedom-to-use studies and trademark litigation and dispute resolution.

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Discuss this

There are currently 11 Comments comments.

  1. Just visiting July 13, 2011 4:12 pm

    This is an amazingly bad decision — even for the Federal Circuit.

    The average age of Plager and Lourie is 78 years old. Really, should they even be on the bench? If this opinion is any indication of the present state of their legal acumen, my vote is an emphatic “no.”

    Radar’s opinion is spot on. Nothing in the specification requies that one-piece body be used. Although it may be advantageous, the limitations of a preferred embodiment should not be incorporated into the claims.

  2. EG July 14, 2011 7:25 am


    Lourie in particular makes me wonder. His opinions in Ariad and Prometheus reached the correct conclusion (in my opinion) but are so convoluted as to be almost unintelligible. As I wrote earlier in IPWatchdog, it’s Newman’s concurring opinion that makes sense of the Ariad decision.

  3. Paul F. Morgan July 14, 2011 3:21 pm

    There have been too many of these panel decisions ignoring claim differentiations to be able to safely rely on that doctrine for claim scope interpretation, even when they are original claims they should also have been legally treated as invention-defining parts of the specification itself, far more relevant than other parts of th specification.
    But unfortunately this particular patent and case had another problem that may have been controlling for the majority. This decision states that: “the Summary of the Invention states that “[t]he invention is a retractable tamperproof syringe,” and that this syringe “features a one piece hollow body.” Id. col.2 ll.45–47.” The Fed. Cir. has repeatedly indicated in other decisions for a number of years now that patent attorneys and agents who [foolishly still continue to dangerously] use a specification sub-title “Summary of the Invention” can get their clients stuck with admissions against interest that the text under that subtitle is designating the protectable scope of the invention. [That subtitle is unfortunately still suggested in a PTO rule, but not required.]
    But this begs the question of why a word in a “Summary of the Invention” should overcome an original claim that does does not have that word, coupled with an original dependent claim that does, thus far more clearly showing the intended claim scope in the specification as filed?
    [Which should not be confused with the case law from “the unpredictable arts” where there is inadequate 112 specification enablement for many species of a generic claim, which is what I think some Fed. Cir. judges have been doing.]

  4. EG July 14, 2011 4:01 pm

    “The Fed. Cir. has repeatedly indicated in other decisions for a number of years now that patent attorneys and agents who [foolishly still continue to dangerously] use a specification sub-title “Summary of the Invention” can get their clients stuck with admissions against interest that the text under that subtitle is designating the protectable scope of the invention.”


    Can you cite me a Federal Circuit case or two in support of this statement? I would be very interested.

    As far as the “Summary of the Invention” section per 37 CFR 1.73, it’s more than simply optional (statement of “the object of the invention” is clearly optional under 37 CFR 1.73 and I definitely don’t list “objects” for reasons relating to how those are treated outside the U.S.). I just refer to it as the “Summary” (never has been objected to by an Examiner and has never posed a problem for me as far as claim scope) and put in what are the basis for each of my independent claims. That’s to comply with what 37 CFR 1.73 also says which that the “Summary” “should be commensurate with the invention claimed.” In fact, if you fail to describe somewhere in the application what the broades scope of the invention is “commensurate with the invention claimed,” you’re flirting with a lack of “written description” and/or “enablement” issue under 35 USC 112, first paragraph. And doing that “broadest description” outside the “Summary” section increases that risk, in my opinion.

    Put differently, the Federal Circuit (as well as us patent practitioners) needs to stop “exalting form unrealistically over substance.” Instead, what is more relevant and important is how you phrase what’s in that “Summary.” The patent applicant in this case simply needed to leave out the “one-piece” reference in that “Summary of the Invention.” (Another nonsensical and oxymoronic view is never using the word “invention” anywhere in the patent application; what, pray tell, are you then describing and claiming?) It would also help to at least illustrate or at least mention that the “body” could be in multiple pieces. Even so, in view of the doctrine of claim differentiation, the result that occurred in this case should have never have happened if the Federal Circuit wants its precedent to be treated as predictable, logical, objective, and consistent.

    The Federal Circuit has a similar problem with when “preamble language” becomes relevant to claim scope/validity, so much so, that if I want the recitation to have “weight,” I put it into the “body” (no pun intended) of the claim, i.e., after the transtional language such as “comprising.” Otherwise, other than a one word description of what statutory class the invention is in (e.g., “commposition,” “device,” “method,” etc.), I usually leave out such “preamble language” so I don’t get the “worst of all worlds,” i.e., the “preamble language” limits the scope of the claim for infringement but is given no weight for validity. Again, the problem is not the “form,” but in exalting that “form” over the “substance.”

  5. Just visiting July 14, 2011 8:18 pm

    “But this begs the question of why a word in a “Summary of the Invention” should overcome an original claim that does does not have that word, coupled with an original dependent claim that does, thus far more clearly showing the intended claim scope in the specification as filed?”

    That’s the real issue. Ultimately, the claims should control — not the specification. Also, despite a one-piece body being a possible preferred embodiment doesn’t mean that it is required. The Examiner did not require the one-piece limitation to distinguish the independent claims over the prior art. Otherwise, the Examiner would have allowed the dependent claim with that limitation and not the limitation. Why should the Federal Circuit import limitations into the independent claims that the Examiner did not think was necessary?

    Sure, this case should serve as a warning to all applicants to avoid the “Summary of the Invention” section altogether. That being said, the Federal Circuit got this wrong — badly.

  6. Gene Quinn July 14, 2011 10:52 pm


    With all due respect, I think you a reading the Federal Circuit cases all wrong. There is absolutely no reason to be afraid of the Summary of the Invention. If you say that the invention is X, then the invention is X. There is nothing wrong with explaining what the core invention is and then throughout the Summary and in the Detailed Description explaining that there are other embodiments. The problem isn’t with folks using a Summary of the Invention, the problem is with the cheap patent applications that have support only for a single embodiment of the invention.


  7. EG July 15, 2011 6:14 am

    “the Federal Circuit got this wrong — badly”

    With regard to Lourie and Plager, that’s an understatement. May be Rader can get the entire Federal Circuit to look at this case en banc. I’m sure Newman would go ballistic over the panel ruling.

  8. Just visiting July 15, 2011 10:02 am

    “There is absolutely no reason to be afraid of the Summary of the Invention.”

    Personally, I don’t see any reason for one. In well over a decade, I have not written one that has been any different than the claims reworded into a proper grammatical structure. I’ve always included them, out of habit. However, there is nothing in the Summary of the Invention that isn’t contained anywhere else. With that in mind, why bother?

  9. Gene Quinn July 15, 2011 10:14 am


    I agree that the Summary shouldn’t typically have anything different than what is contained elsewhere. The only justification I see for having a Summary is that you can actually explain what the invention is in more or less plain English. For many patents the audience will be those who will seek to license, judges who are not technically sophisticated, juries who are not technically sophisticated, investors, partners, etc. I figure that when the reading gets dense is when the lay folks stop reading. Of course, you need to be careful when describing the invention in lay terms. Squirrely lawyer words come in handy… “generally speaking…” “in one version…” “in another version…” etc. etc.


  10. Paul F. Morgan July 15, 2011 10:14 am

    Gene, In view of several CAFC decisions* punishing patentees (by narrowing claim interpretations using in part text under a specification “Summary of the Invention” subtitle, and/or other specification uses of the term “the invention”) several AIPLA and other CLE programs have recommended no long using that subtitle or those words. Thus several major companies and firms have stopped using that subtitle or “section heading” in most of their newer patent applications.

    *E.g., Akeva v. Additas (Fed. Cir. 2006); C. R.Bard Inc. v. U.S. Surgical Corp; No. 04-1135 (Fed. Cir. 10/29/04); SciMed Life Systems Inc. v. Advanced Cardiovascular Systems, Inc. (Fed. Cir. 11/14/01); Storage Technology Corp. v Cisco Systems Inc., 66 USPQ 2d 1545 at 1553 (Fed. Cir. 2003). “[W]hen the preferred embodiment is described in the specification as ‘the invention’ itself, the claims are not necessarily entitled to a scope broader than that embodiment.” Modine Mfg. Co. v. United States Int’l Trade Commission, 75 F.3d 1545, 1551 (Fed. Cir. 1996) (emphasis added); Gaus v. Conair Corp., 70 USPQ2d 1380 at 1384 (Fed. Cir. 2004);

  11. EG July 15, 2011 12:43 pm


    Thanks for noting the cited cases, as well as the recommendations of those AIPLA and CLE programs. I taken a look at the cited cases (as well as other Federal Circuit cases where “Summary of the Invention” was or may have been at issue), and I’m still of the opinion that there is an “overreaction” here as to how the “Summary of the Invention” is treated by the Federal Circuit in these cases. I’ve yet to see a case where the Federal Circuit has limited claim scopie based solely on what is described in a “Summary of the Invention” section. Instead, what I see is that the Federal Circuit cases (including the ones you’ve cited) have viewed what’s described in the “Summary of the Invention” as being consistent with the claim scope being limited by the description in other sections of the application. In fact, in Lucent Technology v. Gateway, the Federal Circuit relied upon what was described in the “Summary of the Invention” section to support a broader claim scope against assertions by the alleged infringer to the contrary.

    Again, what makes “Summary of the Invention” section in Retractable Technologies problematic is that the reference to one-piece “body” there was consistent with the remainder of the description in the application being only to the “body” being a one-piece structure. And given the Federal Circuit’s predelection now to enforce the “possession” component of the “written description” requirement more strictly, it behooves the patent applicant to idenify what the broadest scope of the claimed invention more transparently, which is what the “Summary of the Invention” section can be used for in directly supporting each of the independent claim. Again, the “Summary of the Invention” section in Retractable Technologies is an issue in appropriate drafting such that the rest of specification doesn’t reinforce the limiting the claim scope suggsted by this section, and not a blanket “Summary of the Invention” sections “are always bad” issue.