# MPEP § 2121: Prior Art; General Level of Operability Required to Make a Prima Facie Case > Federal · Agency guidance · In force URL: https://www.frixlaw.com/law-library/statutes/MPEP_S2121 ## Section - **Citation:** MPEP § 2121 - **Heading:** Prior Art; General Level of Operability Required to Make a Prima Facie Case - **Jurisdiction:** Federal - **Kind:** Agency guidance - **Status:** In force - **Text as of:** August 14, 2026 - **Source:** Compiled text - **Location:** USPTO MPEP / Chapter 2100 - Patentability / MPEP § 2121 ## Text I. PRIOR ART IS PRESUMED TO BE OPERABLE/ENABLING When the reference relied on expressly anticipates or makes obvious all of the elements of the claimed invention, the reference is presumed to be operable. Once such a reference is found, the burden is on applicant to rebut the presumption of operability. In re Sasse, 629 F.2d 675, 207 USPQ 107 (CCPA 1980). See also MPEP § 716.07 . See also In re Antor Media Corp., 689 F.3d 1282, 103 USPQ2d 1555 (Fed. Cir. 2012). Specifically, in In re Antor Media Corp., the court stated: “Consistent with the statutory framework and our precedent, we therefore hold that, during patent prosecution, an examiner is entitled to reject claims as anticipated by a prior art publication or patent without conducting an inquiry into whether or not that prior art reference is enabling. As long as an examiner makes a proper prima facie case of anticipation by giving adequate notice under § 132 , the burden shifts to the applicant to submit rebuttal evidence of nonenablement.” In re Antor Media Corp., 689 F.3d at 1289, 103 USPQ2d at 1559. Where a reference appears to not be enabling on its face, however, an applicant may successfully challenge the cited prior art for lack of enablement by argument without supporting evidence. In re Morsa, 713 F.3d 104, 110, 106 USPQ2d 1327, 1332 (Fed. Cir. 2013). See also MPEP § 716.07 . II. WHAT CONSTITUTES AN “ENABLING DISCLOSURE” DOES NOT DEPEND ON THE TYPE OF PRIOR ART THE DISCLOSURE IS CONTAINED IN The level of disclosure required within a reference to make it an “enabling disclosure” is the same no matter what type of prior art is at issue. It does not matter whether the prior art reference is a U.S. patent, foreign patent, a printed publication or other. There is no basis in the statute ( 35 U.S.C. 102 or 103 ) for discriminating either in favor of or against prior art references on the basis of nationality. In re Moreton, 288 F.2d 708, 129 USPQ 227 (CCPA 1961). III sclosure” is the same no matter what type of prior art is at issue. It does not matter whether the prior art reference is a U.S. patent, foreign patent, a printed publication or other. There is no basis in the statute ( 35 U.S.C. 102 or 103 ) for discriminating either in favor of or against prior art references on the basis of nationality. In re Moreton, 288 F.2d 708, 129 USPQ 227 (CCPA 1961). III. EFFICACY IS NOT A REQUIREMENT FOR PRIOR ART ENABLEMENT A prior art reference provides an enabling disclosure and thus anticipates a claimed invention if the reference describes the claimed invention in sufficient detail to enable a person of ordinary skill in the art to carry out the claimed invention; “proof of efficacy is not required for a prior art reference to be enabling for purposes of anticipation.” Impax Labs. Inc. v. Aventis Pharm. Inc., 468 F.3d 1366, 1383, 81 USPQ2d 1001, 1013 (Fed. Cir. 2006) (citing Rasmusson v. SmithKline Beecham Corp., 413 F.3d 1318, 1326, 75 USPQ2d 1297, 1302 (Fed. Cir. 2005)). See also MPEP § 2122 . ## Nearby sections - [MPEP § 2103 Patent Examination Process](https://www.frixlaw.com/law-library/statutes/MPEP_S2103.md) - [MPEP § 2104 Requirements of 35 U.S.C. 101](https://www.frixlaw.com/law-library/statutes/MPEP_S2104.md) - [MPEP § 2104.01 Barred by Atomic Energy Act](https://www.frixlaw.com/law-library/statutes/MPEP_S2104.01.md) - [MPEP § 2105 Patent Eligible Subject Matter — Living Subject Matter](https://www.frixlaw.com/law-library/statutes/MPEP_S2105.md) - [MPEP § 2106 Patent Subject Matter Eligibility](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.md) - [MPEP § 2106.01 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.01.md) - [MPEP § 2106.02 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.02.md) - [MPEP § 2106.03 Eligibility Step 1: The Four Categories of Statutory Subject Matter](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.03.md) - [MPEP § 2106.04 Eligibility Step 2A: Whether a Claim is Directed to a Judicial Exception](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04.md) - [MPEP § 2106.04(a) Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a).md) - [MPEP § 2106.04(a)(1) Examples of Claims That Do Not Recite Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(1).md) - [MPEP § 2106.04(a)(2) Abstract Idea Groupings](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(2).md) - [MPEP § 2106.04(a)(3) Tentative Abstract Ideas](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(a)(3).md) - [MPEP § 2106.04(b) Laws of Nature, Natural Phenomena & Products of Nature](https://www.frixlaw.com/law-library/statutes/MPEP_S2106.04(b).md) --- Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/MPEP_S2121. Check the current official text before relying on it. Not legal advice.