MPEP § 2161 — Three Separate Requirements for Specification Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph (Annotated Rules)

§2161 Three Separate Requirements for Specification Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph

USPTO MPEP version: BlueIron's Update: 2025-12-31

This page consolidates and annotates all enforceable requirements under MPEP § 2161, including statutory authority, regulatory rules, examiner guidance, and practice notes. It is provided as guidance, with links to the ground truth sources. This is information only, it is not legal advice.

Three Separate Requirements for Specification Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph

This section addresses Three Separate Requirements for Specification Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph. Primary authority: 35 U.S.C. 112, 35 U.S.C. 112(a), and 37 CFR 112. Contains: 2 requirements and 6 other statements.

Key Rules

Topic

Enablement Support for Claims

3 rules
StatutoryInformativeAlways
[mpep-2161-cd163b808173aa50b7cc2f9e]
Written Description Requirement Is Separate From Enablement
Note:
The written description requirement must be distinct from the enablement requirement in describing the invention.

The written description requirement is separate and distinct from the enablement requirement. Ariad Pharm., Inc. v. Eli Lilly and Co., 598 F.3d 1336, 1341, 94 USPQ2d 1161, 1167 (Fed. Cir. 2010) (en banc) (If Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently.) Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1562, 19 USPQ2d 1111, 1115 (Fed. Cir. 1991) (While acknowledging that some of its cases concerning the written description requirement and the enablement requirement are confusing, the Federal Circuit reaffirmed that under 35 U.S.C. 112, first paragraph, the written description requirement is separate and distinct from the enablement requirement and gave an example thereof.); In re Barker, 559 F.2d 588, 194 USPQ 470 (CCPA 1977), cert. denied, 434 U.S. 1064 (1978). See also, e.g., Vasudevan Software, Inc. v. MicroStrategy, Inc., 782 F.3d 671, 681-685, 114 USPQ2d 1349, 1356, 1357 (Fed. Cir. 2015) (reversing and remanding the district court's grant of summary judgment of invalidity for lack of an adequate written description and lack of enablement because there were genuine issues of material fact regarding 1) whether the claims had sufficient written description support (“[t]he fact that… the specification do[es] not speak in haec verba of accessing ‘disparate databases’ does not eliminate as a genuine issue of material fact that the existence of at least some discussion, and therefore, possession, of the accessing of disparate databases, as claimed”); and 2) whether the claims were enabled (“the effort it took the inventor to reduce the invention to practice does not conclusively show lack of enablement”). An invention may be described without the disclosure being enabling (e.g., a chemical compound for which there is no disclosed or apparent method of making), and a disclosure could be enabling without describing the invention (e.g., a specification describing a method of making and using a paint composition made of functionally defined ingredients within broad ranges would be enabling for formulations falling within the description but would not describe any specific formulation). See In re Armbruster, 512 F.2d 676, 677, 185 USPQ 152, 153 (CCPA 1975) (“[A] specification which ‘describes’ does not necessarily also ‘enable’ one skilled in the art to make or use the claimed invention.”). Best mode is a separate and distinct requirement from the enablement requirement. In re Newton, 414 F.2d 1400, 163 USPQ 34 (CCPA 1969).

Jump to MPEP Source · 37 CFR 112Enablement Support for ClaimsWritten Description Requirement (MPEP 2163)Specification
StatutoryInformativeAlways
[mpep-2161-0d6862bdcb84009d691aead0]
Written Description Is Separate From Enablement
Note:
The written description requirement and enablement requirement are distinct under § 112, first paragraph.

The written description requirement is separate and distinct from the enablement requirement. Ariad Pharm., Inc. v. Eli Lilly and Co., 598 F.3d 1336, 1341, 94 USPQ2d 1161, 1167 (Fed. Cir. 2010) (en banc) (If Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently.) Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1562, 19 USPQ2d 1111, 1115 (Fed. Cir. 1991) (While acknowledging that some of its cases concerning the written description requirement and the enablement requirement are confusing, the Federal Circuit reaffirmed that under 35 U.S.C. 112, first paragraph, the written description requirement is separate and distinct from the enablement requirement and gave an example thereof.); In re Barker, 559 F.2d 588, 194 USPQ 470 (CCPA 1977), cert. denied, 434 U.S. 1064 (1978). See also, e.g., Vasudevan Software, Inc. v. MicroStrategy, Inc., 782 F.3d 671, 681-685, 114 USPQ2d 1349, 1356, 1357 (Fed. Cir. 2015) (reversing and remanding the district court's grant of summary judgment of invalidity for lack of an adequate written description and lack of enablement because there were genuine issues of material fact regarding 1) whether the claims had sufficient written description support (“[t]he fact that… the specification do[es] not speak in haec verba of accessing ‘disparate databases’ does not eliminate as a genuine issue of material fact that the existence of at least some discussion, and therefore, possession, of the accessing of disparate databases, as claimed”); and 2) whether the claims were enabled (“the effort it took the inventor to reduce the invention to practice does not conclusively show lack of enablement”). An invention may be described without the disclosure being enabling (e.g., a chemical compound for which there is no disclosed or apparent method of making), and a disclosure could be enabling without describing the invention (e.g., a specification describing a method of making and using a paint composition made of functionally defined ingredients within broad ranges would be enabling for formulations falling within the description but would not describe any specific formulation). See In re Armbruster, 512 F.2d 676, 677, 185 USPQ 152, 153 (CCPA 1975) (“[A] specification which ‘describes’ does not necessarily also ‘enable’ one skilled in the art to make or use the claimed invention.”). Best mode is a separate and distinct requirement from the enablement requirement. In re Newton, 414 F.2d 1400, 163 USPQ 34 (CCPA 1969).

Jump to MPEP Source · 37 CFR 112Enablement Support for ClaimsWritten Description Requirement (MPEP 2163)Disclosure Requirements
StatutoryInformativeAlways
[mpep-2161-70d52049fc277faba30dc15f]
Best Mode Is a Separate Requirement from Enablement
Note:
The best mode requirement is distinct from the enablement requirement in patent specification.

The written description requirement is separate and distinct from the enablement requirement. Ariad Pharm., Inc. v. Eli Lilly and Co., 598 F.3d 1336, 1341, 94 USPQ2d 1161, 1167 (Fed. Cir. 2010) (en banc) (If Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently.) Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1562, 19 USPQ2d 1111, 1115 (Fed. Cir. 1991) (While acknowledging that some of its cases concerning the written description requirement and the enablement requirement are confusing, the Federal Circuit reaffirmed that under 35 U.S.C. 112, first paragraph, the written description requirement is separate and distinct from the enablement requirement and gave an example thereof.); In re Barker, 559 F.2d 588, 194 USPQ 470 (CCPA 1977), cert. denied, 434 U.S. 1064 (1978). See also, e.g., Vasudevan Software, Inc. v. MicroStrategy, Inc., 782 F.3d 671, 681-685, 114 USPQ2d 1349, 1356, 1357 (Fed. Cir. 2015) (reversing and remanding the district court's grant of summary judgment of invalidity for lack of an adequate written description and lack of enablement because there were genuine issues of material fact regarding 1) whether the claims had sufficient written description support (“[t]he fact that… the specification do[es] not speak in haec verba of accessing ‘disparate databases’ does not eliminate as a genuine issue of material fact that the existence of at least some discussion, and therefore, possession, of the accessing of disparate databases, as claimed”); and 2) whether the claims were enabled (“the effort it took the inventor to reduce the invention to practice does not conclusively show lack of enablement”). An invention may be described without the disclosure being enabling (e.g., a chemical compound for which there is no disclosed or apparent method of making), and a disclosure could be enabling without describing the invention (e.g., a specification describing a method of making and using a paint composition made of functionally defined ingredients within broad ranges would be enabling for formulations falling within the description but would not describe any specific formulation). See In re Armbruster, 512 F.2d 676, 677, 185 USPQ 152, 153 (CCPA 1975) (“[A] specification which ‘describes’ does not necessarily also ‘enable’ one skilled in the art to make or use the claimed invention.”). Best mode is a separate and distinct requirement from the enablement requirement. In re Newton, 414 F.2d 1400, 163 USPQ 34 (CCPA 1969).

Jump to MPEP Source · 37 CFR 112Enablement Support for ClaimsDetailed DescriptionBest Mode Under AIA
Topic

Considerations for Best Mode (MPEP 2165.01)

2 rules
StatutoryRequiredAlways
[mpep-2161-09201a65097156e1a6b2796e]
Best Mode Must Be Disclosed
Note:
The specification must include the best mode the inventor considered for carrying out the invention, enabling any skilled person to make and use it.

The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention. [emphasis added].

Jump to MPEP SourceConsiderations for Best Mode (MPEP 2165.01)Detailed DescriptionBest Mode Requirement (MPEP 2165)
MPEP GuidanceRequiredAlways
[mpep-2161-4757e1f9d428ee1ff43fc838]
Written Description Must Enable One Skilled In The Art To Make And Use The Invention
Note:
The specification must provide a detailed written description of the invention, enabling any skilled person to understand and implement it, along with the best mode for its implementation.

(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.

Jump to MPEP SourceConsiderations for Best Mode (MPEP 2165.01)Detailed DescriptionBest Mode Requirement (MPEP 2165)
Topic

AIA vs Pre-AIA Practice

2 rules
StatutoryInformativeAlways
[mpep-2161-8f98af0bbcbe03b4768e85bd]
Specification Must Describe Invention Completely
Note:
The specification must provide a detailed written description of the invention, enabling anyone skilled in the relevant field to make and use it, along with disclosing the best mode contemplated by the inventor.

The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention. [emphasis added].

Jump to MPEP SourceAIA vs Pre-AIA PracticeConsiderations for Best Mode (MPEP 2165.01)Detailed Description
StatutoryInformativeAlways
[mpep-2161-56eb870921f22d4f76f45598]
Written Description and Enablement Requirement
Note:
The specification must include a complete written description of the invention, along with how to make and use it.
35 U.S.C. 112(a) and pre-AIA 35 U.S.C. 112, first paragraph require that the specification include the following:
  • (A) A written description of the invention;
  • (B) The manner and process of making and using the invention (the enablement requirement); and
  • (C) The best mode contemplated by the inventor of carrying out his invention.
Jump to MPEP SourceAIA vs Pre-AIA PracticePatent Application ContentConsiderations for Best Mode (MPEP 2165.01)
Topic

AIA Effective Dates

1 rules
StatutoryInformativeAlways
[mpep-2161-d2a312c84115bf62a985ecdb]
Written Description Requirement for Invention
Note:
The rule requires that the specification must describe the invention in full detail to support the claims.

The first paragraph of pre-AIA 35 U.S.C. 112 (applicable to applications filed before September 16, 2012) provides:

Jump to MPEP SourceAIA Effective DatesAIA Overview and Effective DatesAIA vs Pre-AIA Practice
Topic

35 U.S.C. 112(a) – Written Description & Enablement

1 rules
StatutoryInformativeAlways
[mpep-2161-bdbf43c4cb3fe13b3920a341]
Specification Must Describe Invention Completely
Note:
The written description requirement ensures the invention is described in sufficient detail to enable a person skilled in the art to make and use it, separate from the enablement requirement.

The written description requirement is separate and distinct from the enablement requirement. Ariad Pharm., Inc. v. Eli Lilly and Co., 598 F.3d 1336, 1341, 94 USPQ2d 1161, 1167 (Fed. Cir. 2010) (en banc) (If Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently.) Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1562, 19 USPQ2d 1111, 1115 (Fed. Cir. 1991) (While acknowledging that some of its cases concerning the written description requirement and the enablement requirement are confusing, the Federal Circuit reaffirmed that under 35 U.S.C. 112, first paragraph, the written description requirement is separate and distinct from the enablement requirement and gave an example thereof.); In re Barker, 559 F.2d 588, 194 USPQ 470 (CCPA 1977), cert. denied, 434 U.S. 1064 (1978). See also, e.g., Vasudevan Software, Inc. v. MicroStrategy, Inc., 782 F.3d 671, 681-685, 114 USPQ2d 1349, 1356, 1357 (Fed. Cir. 2015) (reversing and remanding the district court's grant of summary judgment of invalidity for lack of an adequate written description and lack of enablement because there were genuine issues of material fact regarding 1) whether the claims had sufficient written description support (“[t]he fact that… the specification do[es] not speak in haec verba of accessing ‘disparate databases’ does not eliminate as a genuine issue of material fact that the existence of at least some discussion, and therefore, possession, of the accessing of disparate databases, as claimed”); and 2) whether the claims were enabled (“the effort it took the inventor to reduce the invention to practice does not conclusively show lack of enablement”). An invention may be described without the disclosure being enabling (e.g., a chemical compound for which there is no disclosed or apparent method of making), and a disclosure could be enabling without describing the invention (e.g., a specification describing a method of making and using a paint composition made of functionally defined ingredients within broad ranges would be enabling for formulations falling within the description but would not describe any specific formulation). See In re Armbruster, 512 F.2d 676, 677, 185 USPQ 152, 153 (CCPA 1975) (“[A] specification which ‘describes’ does not necessarily also ‘enable’ one skilled in the art to make or use the claimed invention.”). Best mode is a separate and distinct requirement from the enablement requirement. In re Newton, 414 F.2d 1400, 163 USPQ 34 (CCPA 1969).

Jump to MPEP Source · 37 CFR 11235 U.S.C. 112(a) – Written Description & EnablementAIA vs Pre-AIA PracticeScope Commensurate with Disclosure
Topic

Scope Commensurate with Disclosure

1 rules
StatutoryInformativeAlways
[mpep-2161-acf63f7d4871016654247696]
Specification Must Describe Invention Completely
Note:
The written description requirement is separate from enablement and must provide sufficient detail for one skilled in the art to practice the invention.

The written description requirement is separate and distinct from the enablement requirement. Ariad Pharm., Inc. v. Eli Lilly and Co., 598 F.3d 1336, 1341, 94 USPQ2d 1161, 1167 (Fed. Cir. 2010) (en banc) (If Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently.) Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1562, 19 USPQ2d 1111, 1115 (Fed. Cir. 1991) (While acknowledging that some of its cases concerning the written description requirement and the enablement requirement are confusing, the Federal Circuit reaffirmed that under 35 U.S.C. 112, first paragraph, the written description requirement is separate and distinct from the enablement requirement and gave an example thereof.); In re Barker, 559 F.2d 588, 194 USPQ 470 (CCPA 1977), cert. denied, 434 U.S. 1064 (1978). See also, e.g., Vasudevan Software, Inc. v. MicroStrategy, Inc., 782 F.3d 671, 681-685, 114 USPQ2d 1349, 1356, 1357 (Fed. Cir. 2015) (reversing and remanding the district court's grant of summary judgment of invalidity for lack of an adequate written description and lack of enablement because there were genuine issues of material fact regarding 1) whether the claims had sufficient written description support (“[t]he fact that… the specification do[es] not speak in haec verba of accessing ‘disparate databases’ does not eliminate as a genuine issue of material fact that the existence of at least some discussion, and therefore, possession, of the accessing of disparate databases, as claimed”); and 2) whether the claims were enabled (“the effort it took the inventor to reduce the invention to practice does not conclusively show lack of enablement”). An invention may be described without the disclosure being enabling (e.g., a chemical compound for which there is no disclosed or apparent method of making), and a disclosure could be enabling without describing the invention (e.g., a specification describing a method of making and using a paint composition made of functionally defined ingredients within broad ranges would be enabling for formulations falling within the description but would not describe any specific formulation). See In re Armbruster, 512 F.2d 676, 677, 185 USPQ 152, 153 (CCPA 1975) (“[A] specification which ‘describes’ does not necessarily also ‘enable’ one skilled in the art to make or use the claimed invention.”). Best mode is a separate and distinct requirement from the enablement requirement. In re Newton, 414 F.2d 1400, 163 USPQ 34 (CCPA 1969).

Jump to MPEP Source · 37 CFR 112Scope Commensurate with DisclosureDescription of EmbodimentsPossession of the Invention (MPEP 2163.02)
Topic

Composition of Matter Claims

1 rules
StatutoryPermittedAlways
[mpep-2161-a4fd71551e6b1011eecacf25]
Invention May Be Described Without Being Enablement
Note:
An invention can be described in the specification even if there is no disclosed method of making it, and a disclosure can be enabling without describing specific formulations.

The written description requirement is separate and distinct from the enablement requirement. Ariad Pharm., Inc. v. Eli Lilly and Co., 598 F.3d 1336, 1341, 94 USPQ2d 1161, 1167 (Fed. Cir. 2010) (en banc) (If Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently.) Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1562, 19 USPQ2d 1111, 1115 (Fed. Cir. 1991) (While acknowledging that some of its cases concerning the written description requirement and the enablement requirement are confusing, the Federal Circuit reaffirmed that under 35 U.S.C. 112, first paragraph, the written description requirement is separate and distinct from the enablement requirement and gave an example thereof.); In re Barker, 559 F.2d 588, 194 USPQ 470 (CCPA 1977), cert. denied, 434 U.S. 1064 (1978). See also, e.g., Vasudevan Software, Inc. v. MicroStrategy, Inc., 782 F.3d 671, 681-685, 114 USPQ2d 1349, 1356, 1357 (Fed. Cir. 2015) (reversing and remanding the district court's grant of summary judgment of invalidity for lack of an adequate written description and lack of enablement because there were genuine issues of material fact regarding 1) whether the claims had sufficient written description support (“[t]he fact that… the specification do[es] not speak in haec verba of accessing ‘disparate databases’ does not eliminate as a genuine issue of material fact that the existence of at least some discussion, and therefore, possession, of the accessing of disparate databases, as claimed”); and 2) whether the claims were enabled (“the effort it took the inventor to reduce the invention to practice does not conclusively show lack of enablement”). An invention may be described without the disclosure being enabling (e.g., a chemical compound for which there is no disclosed or apparent method of making), and a disclosure could be enabling without describing the invention (e.g., a specification describing a method of making and using a paint composition made of functionally defined ingredients within broad ranges would be enabling for formulations falling within the description but would not describe any specific formulation). See In re Armbruster, 512 F.2d 676, 677, 185 USPQ 152, 153 (CCPA 1975) (“[A] specification which ‘describes’ does not necessarily also ‘enable’ one skilled in the art to make or use the claimed invention.”). Best mode is a separate and distinct requirement from the enablement requirement. In re Newton, 414 F.2d 1400, 163 USPQ 34 (CCPA 1969).

Jump to MPEP Source · 37 CFR 112Composition of Matter ClaimsMethod/Process ClaimsPatent Application Content
Topic

Determining Whether Application Is AIA or Pre-AIA

1 rules
StatutoryInformativeAlways
[mpep-2161-a60e68e3fe9b237ff82b6d95]
Specification Must Not Necessarily Enable Invention
Note:
A specification that describes an invention does not necessarily enable one skilled in the art to make or use it.

The written description requirement is separate and distinct from the enablement requirement. Ariad Pharm., Inc. v. Eli Lilly and Co., 598 F.3d 1336, 1341, 94 USPQ2d 1161, 1167 (Fed. Cir. 2010) (en banc) (If Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently.) Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1562, 19 USPQ2d 1111, 1115 (Fed. Cir. 1991) (While acknowledging that some of its cases concerning the written description requirement and the enablement requirement are confusing, the Federal Circuit reaffirmed that under 35 U.S.C. 112, first paragraph, the written description requirement is separate and distinct from the enablement requirement and gave an example thereof.); In re Barker, 559 F.2d 588, 194 USPQ 470 (CCPA 1977), cert. denied, 434 U.S. 1064 (1978). See also, e.g., Vasudevan Software, Inc. v. MicroStrategy, Inc., 782 F.3d 671, 681-685, 114 USPQ2d 1349, 1356, 1357 (Fed. Cir. 2015) (reversing and remanding the district court's grant of summary judgment of invalidity for lack of an adequate written description and lack of enablement because there were genuine issues of material fact regarding 1) whether the claims had sufficient written description support (“[t]he fact that… the specification do[es] not speak in haec verba of accessing ‘disparate databases’ does not eliminate as a genuine issue of material fact that the existence of at least some discussion, and therefore, possession, of the accessing of disparate databases, as claimed”); and 2) whether the claims were enabled (“the effort it took the inventor to reduce the invention to practice does not conclusively show lack of enablement”). An invention may be described without the disclosure being enabling (e.g., a chemical compound for which there is no disclosed or apparent method of making), and a disclosure could be enabling without describing the invention (e.g., a specification describing a method of making and using a paint composition made of functionally defined ingredients within broad ranges would be enabling for formulations falling within the description but would not describe any specific formulation). See In re Armbruster, 512 F.2d 676, 677, 185 USPQ 152, 153 (CCPA 1975) (“[A] specification which ‘describes’ does not necessarily also ‘enable’ one skilled in the art to make or use the claimed invention.”). Best mode is a separate and distinct requirement from the enablement requirement. In re Newton, 414 F.2d 1400, 163 USPQ 34 (CCPA 1969).

Jump to MPEP Source · 37 CFR 112Determining Whether Application Is AIA or Pre-AIAEnablement Support for ClaimsDetermining AIA vs Pre-AIA Applicability (MPEP 2159)

Citations

Primary topicCitation
35 U.S.C. 112(a) – Written Description & Enablement
AIA Effective Dates
AIA vs Pre-AIA Practice
Composition of Matter Claims
Determining Whether Application Is AIA or Pre-AIA
Enablement Support for Claims
Scope Commensurate with Disclosure
35 U.S.C. § 112
AIA vs Pre-AIA Practice35 U.S.C. § 112(a)
35 U.S.C. 112(a) – Written Description & Enablement
Composition of Matter Claims
Determining Whether Application Is AIA or Pre-AIA
Enablement Support for Claims
Scope Commensurate with Disclosure
In re Armbruster, 512 F.2d 676, 677, 185 USPQ 152, 153 (CCPA 1975)
35 U.S.C. 112(a) – Written Description & Enablement
Composition of Matter Claims
Determining Whether Application Is AIA or Pre-AIA
Enablement Support for Claims
Scope Commensurate with Disclosure
In re Barker, 559 F.2d 588, 194 USPQ 470 (CCPA 1977)
35 U.S.C. 112(a) – Written Description & Enablement
Composition of Matter Claims
Determining Whether Application Is AIA or Pre-AIA
Enablement Support for Claims
Scope Commensurate with Disclosure
In re Newton, 414 F.2d 1400, 163 USPQ 34 (CCPA 1969)
35 U.S.C. 112(a) – Written Description & Enablement
Composition of Matter Claims
Determining Whether Application Is AIA or Pre-AIA
Enablement Support for Claims
Scope Commensurate with Disclosure
Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1562, 19 USPQ2d 1111, 1115 (Fed. Cir. 1991)

Source Text from USPTO’s MPEP

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BlueIron Last Updated: 2025-12-31