Skip over navigation

2103 Patent Examination Process [R-07.2022]


It is essential that patent applicants obtain a prompt yet complete examination of their applications. Under the principles of compact prosecution, each claim should be reviewed for compliance with every statutory requirement for patentability in the initial review of the application, even if one or more claims are found to be deficient with respect to some statutory requirement. Thus, examiners should state all reasons and bases for rejecting claims in the first Office action. Deficiencies should be explained clearly, particularly when they serve as a basis for a rejection. Whenever practicable, examiners and patent reexamination specialists should indicate how rejections may be overcome and how problems may be resolved. Where a rejection not based on prior art is proper (lack of adequate written description, enablement, or utility, etc.) such rejection should be stated with a full development of the reasons rather than by a mere conclusion. A failure to follow this approach can lead to unnecessary delays in the prosecution of the application.

The examination of reissue applications is covered in MPEP Chapter 1400, reexamination proceedings are covered in MPEP Chapters 2200 (ex parte) and 2600 (inter partes), and supplemental examination is covered in MPEP Chapter 2800.

Prior to focusing on specific statutory requirements, examiners must begin examination by determining what, precisely, the inventor or joint inventor has invented and is seeking to patent, and how the claims relate to and define that invention. Examiners will review the complete specification, including the detailed description of the invention, any specific embodiments that have been disclosed, the claims and any specific, substantial, and credible utilities that have been asserted for the invention.

After obtaining an understanding of the invention, the examiner will conduct a search of the prior art and determine whether the invention as claimed complies with all statutory requirements.

A. Identify and Understand Any Utility for the Invention

The claimed invention as a whole must be useful. The purpose of this requirement is to limit patent protection to inventions that possess a certain level of “real world” value, as opposed to subject matter that represents nothing more than an idea or concept, or is simply a starting point for future investigation or research (Brenner v. Manson, 383 U.S. 519, 528-36, 148 USPQ 689, 693-96 (1966); In re Fisher, 421 F.3d 1365, 76 USPQ2d 1225 (Fed. Cir. 2005); In re Ziegler, 992 F.2d 1197, 1200-03, 26 USPQ2d 1600, 1603-06 (Fed. Cir. 1993)).

Examiners should review the application to identify any asserted utility. The applicant or the inventor is in the best position to explain why an invention is useful. Accordingly, a complete disclosure should contain some indication of the practical application for the claimed invention, i.e., why the applicant asserts the claimed invention is useful. Such a statement will usually explain the purpose of the invention or how the invention may be used (e.g., a compound is believed to be useful in the treatment of a particular disorder). Note that the concept of a “practical application” in the evaluation of utility is different from the concept of whether a judicial exception is integrated into a “practical application” in the evaluation of subject matter eligibility. Regardless of the form of statement of utility, it must enable one ordinarily skilled in the art to understand why the applicant asserts the claimed invention is useful. See MPEP § 2106 for subject matter eligibility guidelines and MPEP § 2107 for utility examination guidelines. The application may describe more than one utility and practical application, but only one is necessary. Alternatively, an applicant may rely on the contemporaneous art to provide that the claimed invention has a well-established utility.

B. Review the Detailed Disclosure and Specific Embodiments of the Invention To Understand What the Applicant Has Asserted as the Invention

The written description will provide the clearest explanation of the invention, by exemplifying the invention, explaining how it relates to the prior art and explaining the relative significance of various features of the invention. Accordingly, examiners should continue their evaluation by:

  • (A) determining the function of the invention, that is, what the invention does when used as disclosed (e.g., the functionality of a programmed computer); and
  • (B) determining the features necessary to accomplish at least one asserted practical application.

Patent applicants can assist the USPTO by preparing applications that clearly set forth these aspects of an invention.

C. Review the Claims

The claims define the property rights provided by a patent, and thus require careful scrutiny. The goal of claim analysis is to identify the boundaries of the protection sought by the applicant and to understand how the claims relate to and define what the applicant has indicated is the invention. Examiners must first determine the scope of a claim by thoroughly analyzing the language of the claim before determining if the claim complies with each statutory requirement for patentability. See In re Hiniker Co., 150 F.3d 1362, 1369, 47 USPQ2d 1523, 1529 (Fed. Cir. 1998) (“[T]he name of the game is the claim.”).

Examiners should begin claim analysis by identifying and evaluating each claim limitation. For processes, the claim limitations will define steps or acts to be performed. For products, the claim limitations will define discrete physical structures or materials. Product claims are claims that are directed to either machines, manufactures or compositions of matter.

Examiners should then correlate each claim limitation to all portions of the disclosure that describe the claim limitation. This is to be done in all cases, regardless of whether the claimed invention is defined using means- (or step-) plus- function language. The correlation step will ensure that examiners correctly interpret each claim limitation in light of the specification.

The subject matter of a properly construed claim is defined by the terms that limit the scope of the claim when given their broadest reasonable interpretation. It is this subject matter that must be examined. As a general matter, grammar and the plain meaning of terms as understood by one having ordinary skill in the art used in a claim will dictate whether, and to what extent, the language limits the claim scope. See MPEP § 2111.01 for more information on the plain meaning of claim language. Language that suggests or makes a feature or step optional but does not require that feature or step does not limit the scope of a claim under the broadest reasonable claim interpretation. The following types of claim language may raise a question as to its limiting effect:

  • (A) statements of intended use or field of use, including statements of purpose or intended use in the preamble,
  • (B) “adapted to” or “adapted for” clauses,
  • (C) "wherein" or "whereby" clauses,
  • (D) contingent limitations,
  • (E) printed matter, or
  • (F) terms with associated functional language.

This list of examples is not intended to be exhaustive. The determination of whether particular language is a limitation in a claim depends on the specific facts of the case. See, e.g., Griffin v. Bertina, 285 F.3d 1029, 1034, 62 USPQ2d 1431 (Fed. Cir. 2002)(finding that a “wherein” clause limited a process claim where the clause gave “meaning and purpose to the manipulative steps”). For more information about these types of claim language and how to determine whether they have a limiting effect on claim scope, see MPEP §§ 2111.02 through 2111.05.

Examiners are to give claims their broadest reasonable interpretation in light of the supporting disclosure. See MPEP § 2111. Disclosure may be express, implicit, or inherent. Examiners are to give claimed means- (or step-) plus- function limitations their broadest reasonable interpretation consistent with all corresponding structures (or materials or acts) described in the specification and their equivalents. See In re Aoyama, 656 F.3d 1293, 1297, 99 USPQ2d 1936, 1939 (Fed. Cir. 2011). Further guidance in interpreting the scope of equivalents is provided in MPEP §§ 2181 through 2186.

While it is appropriate to use the specification to determine what applicant intends a term to mean, a positive limitation from the specification cannot be read into a claim that does not itself impose that limitation. See MPEP § 2111.01, subsection II. As explained in MPEP § 2111, giving a claim its broadest reasonable interpretation during prosecution will reduce the possibility that the claim, when issued, will be interpreted more broadly than is justified.

Finally, when evaluating the scope of a claim, every limitation in the claim must be considered. Examiners may not dissect a claimed invention into discrete elements and then evaluate the elements in isolation. Instead, the claim as a whole must be considered. See, e.g., Diamond v. Diehr, 450 U.S. 175, 188-89, 209 USPQ 1, 9 (1981) (“In determining the eligibility of respondents’ claimed process for patent protection under § 101, their claims must be considered as a whole. It is inappropriate to dissect the claims into old and new elements and then to ignore the presence of the old elements in the analysis. This is particularly true in a process claim because a new combination of steps in a process may be patentable even though all the constituents of the combination were well known and in common use before the combination was made.”).


Prior to evaluating the claimed invention for patentability, examiners are expected to conduct a thorough search of the prior art. See MPEP §§ 904 through 904.03 for more information about how to conduct a search. In many cases, the result of such a search will contribute to examiners' understanding of the invention. Both claimed and unclaimed aspects of the invention described in the specification should be searched if there is a reasonable expectation that the unclaimed aspects may be later claimed. A search must take into account any structure or material described in the specification and its equivalents which correspond to the claimed means- (or step-) plus- function limitation, in accordance with 35 U.S.C. 112(f) and MPEP § 2181 through MPEP § 2186.

A. Consider the Breadth of 35 U.S.C. 101 Under Controlling Law

Section 101 of title 35, United States Code, provides:

Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.

35 U.S.C. 101 has been interpreted as imposing four requirements: (i) only one patent may be obtained for an invention; (ii) the inventor(s) must be identified in an application filed on or after September 16, 2012 or must be the applicant in applications filed before September 16, 2012; (iii) the claimed invention must be eligible for patenting; and (iv) the claimed invention must be useful (have utility).

See MPEP § 2104 for a discussion of the four requirements, MPEP § 2106 for a discussion of eligibility, and MPEP § 2107 for the utility examination guidelines.

The patent eligibility inquiry under 35 U.S.C. 101 is a threshold inquiry. Even if a claimed invention qualifies as eligible subject matter under 35 U.S.C. 101, it must also satisfy the other conditions and requirements of the patent laws, including the requirements for novelty (35 U.S.C. 102), nonobviousness (35 U.S.C. 103), and adequate description and definite claiming (35 U.S.C. 112). Bilski v. Kappos, 561 U.S. 593, 602, 95 USPQ2d 1001, 1006 (2010). Therefore, examiners should avoid focusing on only issues of patent-eligibility under 35 U.S.C. 101 to the detriment of considering an application for compliance with the requirements of 35 U.S.C. 102, 35 U.S.C. 103, and 35 U.S.C. 112, and should avoid treating an application solely on the basis of patent-eligibility under 35 U.S.C. 101 except in the most extreme cases.

A. Determine Whether the Claimed Invention Complies with 35 U.S.C. 112(b) or Pre-AIA 35 U.S.C. 112, Second Paragraph Requirements

35 U.S.C. 112(b) contains two separate and distinct requirements: (A) that the claim(s) set forth the subject matter the inventor or a joint inventor regards as the invention, and (B) that the claim(s) particularly point out and distinctly claim the invention. An application will be deficient under the first requirement of 35 U.S.C. 112(b) when evidence outside the application as filed, e.g., admissions, shows that the inventor or a joint inventor regards the invention to be different from what is claimed (see MPEP § 2171 - MPEP § 2172.01).

An application fails to comply with the second requirement of 35 U.S.C. 112(b) when the claims do not set out and define the invention with a reasonable degree of precision and particularity. In this regard, the definiteness of the language must be analyzed, not in a vacuum, but always in light of the teachings of the disclosure as it would be interpreted by one of ordinary skill in the art. Applicant’s claims, interpreted in light of the disclosure, must reasonably apprise a person of ordinary skill in the art of the invention.

The scope of a limitation that invokes 35 U.S.C. 112(f) is defined as the corresponding structure or material set forth in the written description and equivalents thereof that perform the claimed function. See MPEP § 2181 through MPEP § 2186. See MPEP § 2173et seq. for a discussion of a variety of issues pertaining to the 35 U.S.C. 112(b) requirement that the claims particularly point out and distinctly claim the invention.

B. Determine Whether the Claimed Invention Complies with 35 U.S.C. 112(a) or 35 U.S.C. 112, First Paragraph Requirements

35 U.S.C. 112(a) contains three separate and distinct requirements:

  • (A) adequate written description,
  • (B) enablement, and
  • (C) best mode.
1. Adequate Written Description

For the written description requirement, an applicant’s specification must reasonably convey to those skilled in the art that the inventor was in possession of the claimed invention as of the date of invention. See MPEP § 2163 for further guidance with respect to the evaluation of a patent application for compliance with the written description requirement.

2. Enabling Disclosure

An applicant’s specification must enable a person skilled in the art to make and use the claimed invention without undue experimentation. The fact that experimentation is complex, however, will not make it undue if a person of skill in the art routinely engages in such experimentation.

See MPEP § 2164et seq. for detailed guidance with regard to the enablement requirement of 35 U.S.C. 112(a).

3. Best Mode

Determining compliance with the best mode requirement requires a two-prong inquiry:

  • (1) at the time the application was filed, did the inventor possess a best mode for practicing the invention; and
  • (2) if the inventor did possess a best mode, does the written description disclose the best mode in such a manner that a person of ordinary skill in the art could practice the best mode.

See MPEP § 2165et seq. for additional guidance. Deficiencies related to disclosure of the best mode for carrying out the claimed invention are not usually encountered during examination of an application because evidence to support such a deficiency is seldom in the record. Fonar Corp. v. General Elec. Co., 107 F.3d 1543, 1548-49, 41 USPQ2d 1801, 1804-05 (Fed. Cir. 1997).


Reviewing a claimed invention for compliance with 35 U.S.C. 102 and 35 U.S.C.103 begins with a comparison of the claimed subject matter to what is known in the prior art. See MPEP §§ 2131 - 2146 and MPEP §§ 2150 - 2159 for specific guidance on patentability determinations under 35 U.S.C. 102 and 35 U.S.C. 103. If no differences are found between the claimed invention and the prior art, then the claimed invention lacks novelty and is to be rejected by USPTO personnel under 35 U.S.C. 102. Once differences are identified between the claimed invention and the prior art, those differences must be assessed and resolved in light of the knowledge possessed by a person of ordinary skill in the art. Against this backdrop, one must determine whether the invention would have been obvious to one of ordinary skill in the art. If not, the claimed invention satisfies 35 U.S.C. 103.


Once examiners have completed the above analyses of the claimed invention under all the statutory provisions, including 35 U.S.C. 101, 35 U.S.C. 112, 35 U.S.C. 102, and 35 U.S.C. 103, they should review all the proposed rejections and their bases to confirm that a prima facie case of unpatentability exists. Only then should any rejection be imposed in an Office action. The Office action should clearly communicate the findings, conclusions and reasons which support them.




United States Patent and Trademark Office
This page is owned by Patents.
Last Modified: 02/16/2023 12:58:19