Prosecution Insights
Last updated: April 19, 2026
Application No. 16/245,063

SYSTEMS AND METHODS FOR ELECTROCHEMICAL CREATININE ASSAYS AND BLOOD UREA NITROGEN

Final Rejection §103
Filed
Jan 10, 2019
Examiner
GOUGH, TIFFANY MAUREEN
Art Unit
1651
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Polymer Technology Systems Inc.
OA Round
10 (Final)
31%
Grant Probability
At Risk
11-12
OA Rounds
4y 5m
To Grant
80%
With Interview

Examiner Intelligence

Grants only 31% of cases
31%
Career Allow Rate
158 granted / 507 resolved
-28.8% vs TC avg
Strong +49% interview lift
Without
With
+49.2%
Interview Lift
resolved cases with interview
Typical timeline
4y 5m
Avg Prosecution
41 currently pending
Career history
548
Total Applications
across all art units

Statute-Specific Performance

§101
4.3%
-35.7% vs TC avg
§103
39.9%
-0.1% vs TC avg
§102
18.3%
-21.7% vs TC avg
§112
21.1%
-18.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 507 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Applicant’s response filed 11/11/2025 has been received and entered into the case. All arguments and amendments have been considered. Claims 1, 6, 8, 13-26 are pending. Claims 13-25 are withdrawn. Claims 1, 6, 8, 26 have been considered on the merits. All arguments and amendments have been considered. Claim Interpretation The claims are drawn to a system for detecting an analyte comprising a test strip, having an electrode and counter electrode, and a coating on the electrodes including reagents. The analyte is claimed to be creatinine and urea. As previously addressed, the limitations of blood being usable in claims 1, 8, and new claim 26 do not provide a structural component to the system and the use of a material or article worked upon by a structure does not impart patentability to the claims, i.e., directed as blood being “usable” in the claimed system. The claims are drawn to a system for detection of an analyte however the claims do not require a step of detecting creatinine or urea per se but rather reagents to produce NH3 and NAD+. The “wherein” phrase “wherein the NAD+ is amplified by the enzyme cycling system, in that NAD+ is created by reaction with Diaphorase, which are collectively creatinine reactions and measure creatinine in a sample on the test strip, wherein the creatinine reactions are immune to oxygen and oxygen is not present in the creatinine reactions so both venous and capillary blood is usable”, does not impart structure to the claimed system, are taken to be results of the enzymatic reactions when combining the reagents, and thus does not impart patentability to the claims. Claim Objections Claims 1 and 8 are objected to because of the following informalities: urease is misspelled in each claim as “urase”. Appropriate correction is required. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1, 6, 8, 26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hughes et al. (US2016/0327562 A1) in view of Hughes et al. (US2017/0284954), Shull (US2004/0126833A1), Yamaguchi et al. (Clinica Chimica Acta. 352: 165-173, 2005), JP2003279525(IDS), Yamaguchi et al. (Biosci. Biotech. Biochem, p. 2052-2059, 2002) supported by Gambhir (Appl. BIochem, 2001, IDS) in further view of Winarta et al. (US20070131548). Hughes teaches a system for the electrochemical detection of analyte levels (a ketone and glucose) comprising a test strip including a first electrode and a first counter electrode located proximate to a sample reception area for detecting a first analyte, i.e. ketones, and a second electrode and counter electrode located proximate to a second sample reception area and a coating on one of the electrodes to detect a second analyte (abstract, 0003, 0004). The coating of the system is disclosed to comprise a ferricyanide as the mediator and a dehydrogenase enzyme, diaphorase, a buffer and a surfactant (0003-0005). Hughes teaches the system to be used for electrochemical detection of ketone and glucose levels. Regarding claim 26, the coating may include hydroxybutyrate, hydroxybutyrate dehydrogenase, a mediator and NAD (0003, 0004, 0023-0026) Hughes teaches the enzymatic reaction pathway; it can be seen that NAD+ with a dehydrogenase enzyme produces NADH. The NADH with mediator and diaphorase produces NAD+ (0025). PNG media_image1.png 216 578 media_image1.png Greyscale Regarding claim 8, the system of Hughes comprises an analyzer, i.e., a microprocessor for receiving the test strip and having software or firmware as a form of instructions containing in or on a non-transitory computer-readable storage medium including ROM and RAM which may be read and executed by the processors (0034). Hughes differ from the claimed invention in that they do not teach the reagents (creatinine iminohydrolase, deamido NAD+, ATP, NAD synthetase/Mg2+, glucose, glucose dehydrogenase, the claimed mediators and diaphorase) for detecting the analyte creatinine as claimed in claims 1, 8, and 26. Regarding the mediators of claims 1, 8, and 26, Hughes (US’954) teaches a system for the electrochemical detection of an analyte comprising a test strip including an electrode and counter electrode located proximate to a sample reception area and a coating including a reagent coating for the analyte, specifically for creatinine. The reagent comprises a surfactant, binder and a mediator, wherein the mediator for use in creatinine electrochemical reactions with a dehydrogenase is selected from meldora blue, phenazine methosulfate, 2,6-diclorophenol indophenol, potassium ferricyanide, and nile blue (0005-0008, 0029). The system also comprises an analyzer for receiving the test strip including instructions for stored on a non-transitory medium for applying a current to the test strip and responsively determining an amount of creatinine (0006, 0007). Hughes additionally teaches that the reactions are not dependent on oxygen and can test both venous and capillary blood (0020). Therefore, before the effective filing date of the claimed invention, mediators for use in creatinine electrochemical systems were known in the art. One of ordinary skill in the art could have substituted one known mediator for another and the results would have been predictable. Thus, one could have substituted the ferricyanide of Hughes with the mediators disclosed by Hughes (‘954) with a reasonable expectation of success. Regarding the reagents for detecting an analyte, Shull (US2004/0126833) teach a test strip for determining creatinine in a body fluid. Shull teach the reaction pathway for the enzymatic determination of creatinine. PNG media_image2.png 330 547 media_image2.png Greyscale It can be seen from the pathway that creatinine iminohydrolase reacts with creatinine to produce ammonia NH3. Yamaguchi teaches an enzymatic cycling method for detecting the analyte ammonia NH3 using NAD synthetase. Yamaguchi teaches that the new method of ammonia assay ensures sensitive, precise, and accurate assay of ammonia in biological samples containing substances such as urea and creatinine due to the fact that NAD synthetase is highly specific for ammonia (page 171, col. 1, paragraph 1). The method uses NAD synthetase, glucose dehydrogenase, and diaphorase (page 166, col. 2, paragraph 2). Yamaguchi further teaches that the reaction necessary for assaying ammonia using these enzymes also requires ATP, deamino-NAD, and glucose (page 166, col. 2, paragraph 2; Fig. 1). NAD synthetase requires ATP and deamino-NAD to assay ammonia by converting it into NAD (Fig. 1, page 171, col. 1, paragraph 1); glucose and the NAD produced from ammonia is required by glucose dehydrogenase and produces NADH (Fig. 1); the NADH is used by the diaphorase to produce a formazan dye that is then measured as the final product (page 166, col. 2, paragraph 2; Fig. 1). Yamaguchi teaches the presence of MgCl2 in reagent 1 (R1) (p. 167, section 2.2.) PNG media_image3.png 200 400 media_image3.png Greyscale Further, JP525 teaches an electrode system which is highly sensitive, simple and speedy to measure NH3 using a reagent comprising diaphorase, dehydrogenase (p. 7), diamino-NAD+, ATP, NAD synthetase/Mg2+(p. 7, 9), a mediator including potassium ferricyanide, methylene blue (p. 9), a surfactant a buffer (p. 10)(abstract, p. 6-11). Yamaguchi (2002) teach the use of Mg2+ in Reagent 1 (R1) with the enzyme NAD synthetase. Yamaguchi teaches that their NAD synthetase was prepared according to Yamaguchi (Biosci. Biotech. Biochem, 2002) which specifically teaches that metal ions such as Mg2+ are needed for NAD synthetase activity to catalyze the final conversion of deamide-NAD to NAD in the presence of ATP and ammonia (p. 2056, last parag. and Fig. 3, p. 2058, Discussion section). Therefore, it would have been obvious before the effective filing date of the claimed invention to use Mg2+ in complex NAD synthetase as it maximizes the enzymes activity. Therefore, it would have been obvious before the effective filing date of the claimed invention to have used the reagents of Shull, Yamaguchi and JP525 in the system of Hughes for detecting an analyte, wherein the analyte is creatinine because the art collectively teaches the enzymatic reaction pathways wherein creatinine iminohydrolase reacts with creatinine to produce ammonia (NH3) and NH3 is enzymatically converted by reacting NH3 with deamino-NAD + ATP+ NAD synthetase to produce NAD+AMP+ pyrophosphate. The NAD is then amplified by an enzyme cycling system of glucose dehydrogenase and diaphorase (page 166, col. 2, paragraph 2) to produce NADH and D-gluco-δ-lactone, or HBA and HBA dehydrogenase (as taught by Hughes US’562). One would have a reasonable expectation of successfully using the NADH in step (2) of the reaction pathway of Hughes with the mediator and diaphorase to produce NAD+, thereby meeting the limitation of the NAD+ being amplified by the enzyme cycling system and creating NAD+ by reaction with diaphorase according to claim 1, 8 and 26 (using either glucose and glucose dehydrogenase or HBS and HBA dehydrogenase). The NADH with mediator and diaphorase produces NAD+ in Hughes. Therefore, one would have a reasonable expectation of successfully using the reagents of Shull and Yamaguchi in the coating of Hughes to determine creatinine given the arts enzymatic pathway systems and reagents used therefore. Regarding newly added limitations to claims 1 and 8, drawn to a second analyte being urea and the coating on the second electrode including urease, deamido NAD+, ATP, NAD synthetase/Mg2+ , glucose and glucose dehydrogenase, diaphorase and a mediator, it is known in the art that the reaction of urea with urease produces ammonia (NH3), support is provided by Gambhir who teach that the hydrolysis of urea is catalyzed by urease releasing ammonia and the oxidation of NADH to NAD (p. 250, last parag). Therefore, before the effective filing date of the claimed invention, one of ordinary skill in the art would have a reasonable expectation of successfully using the reagents of Yamaguchi in a system to detect urease because the art teaches the assay of ammonia in biological samples containing substances such as urea and creatinine. NAD synthetase is taught to be highly specific for ammonia (page 171, col. 1, paragraph 1) and thus uses NAD synthetase, glucose dehydrogenase, and diaphorase (page 166, col. 2, paragraph 2). Yamaguchi further teaches that the reaction necessary for assaying ammonia using these enzymes also requires ATP, deamino-NAD, and glucose (page 166, col. 2, paragraph 2; Fig. 1). NAD synthetase requires ATP and deamino-NAD to assay ammonia by converting it into NAD (Fig. 1, page 171, col. 1, paragraph 1); glucose and the NAD produced from ammonia is required by glucose dehydrogenase and produces NADH (Fig. 1); the NADH is used by the diaphorase to produce a formazan dye that is then measured as the final product. Therefore, the one would have had a reasonable expectation of successfully detecting urea when using the reagents of Yamaguchi because it was known that the hydrolysis of urea by urease releases ammonia, which is then used in the enzyme cycle of Yamaguchi to create an detectable electrochemical product. Regarding the newly added limitation of the analyzer reporting a creatinine to urea ratio, Winarta teaches an electrochemical sensor system for determining creatinine to urea ratio in blood (0002, 0015, 0016). Urea (BUN) and creatinine are commonly screened for the evaluation of kidney function and the BUN-to-creatinine ratio is also typically used to determine decreased kidney function including kidney failure and other diseases and conditions (0004, 0010-0014). The system of Winarta comprises a test strip at least one electrode and counter electrode (0019, 0021, Fig. 1, Fig. 3) and reagents including urease, a surfactant, buffer, and mediator (0024, 0025, 0026). The system includes additional electrodes having creatinine/creatine sensitive enzymes, a surfactant, buffer and mediator (0032, 0034, 0035, 0038, 0042) and thus the multiple electrode system allows one to measure the urea-to-creatinine ratio (0032, 0038). Thus, before the effective filing date of the claimed invention, it would have been obvious to a posita to include test strips, electrodes and reagents for detecting both creatinine and urea in a system because Winarta teaches that both analytes are useful to determining kidney function, diseases and other related conditions. PNG media_image4.png 1 1 media_image4.png Greyscale PNG media_image4.png 1 1 media_image4.png Greyscale Regarding the limitations of blood being usable, the art teaches the claimed creatinine reactions and the reagents and test strips of the prior art are disclosed to be used with blood and plasma samples. Regardless of the use of blood, the limitations of claim 1 and 8 do not provide a structural component to the system and the use of a material or article worked upon by a structure does not impart patentability to the claims. Response to Arguments Applicant’s arguments with respect to the claim(s) have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Applicants argument is directed toward the claim amendments including a test for urea and analyzing urea to creatinine ratios. New reference Winarta has been relied upon herein to support the rejection of the newly added limitations. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to TIFFANY MAUREEN GOUGH whose telephone number is (571)272-0697. The examiner can normally be reached M-Thu 8-5. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Melenie Gordon can be reached at 571-272-8037. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /TIFFANY M GOUGH/Examiner, Art Unit 1651 /MELENIE L GORDON/Supervisory Patent Examiner, Art Unit 1651
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Prosecution Timeline

Jan 10, 2019
Application Filed
Sep 30, 2020
Non-Final Rejection — §103
Apr 06, 2021
Response Filed
Jul 28, 2021
Final Rejection — §103
Nov 02, 2021
Response after Non-Final Action
Dec 01, 2021
Request for Continued Examination
Dec 06, 2021
Response after Non-Final Action
Jun 15, 2022
Non-Final Rejection — §103
Nov 21, 2022
Response Filed
Jan 19, 2023
Final Rejection — §103
May 25, 2023
Response after Non-Final Action
Jul 25, 2023
Request for Continued Examination
Jul 31, 2023
Response after Non-Final Action
Sep 08, 2023
Non-Final Rejection — §103
Dec 13, 2023
Response Filed
Mar 11, 2024
Final Rejection — §103
Aug 19, 2024
Request for Continued Examination
Aug 20, 2024
Response after Non-Final Action
Aug 28, 2024
Non-Final Rejection — §103
Dec 04, 2024
Response Filed
Jan 21, 2025
Final Rejection — §103
May 28, 2025
Request for Continued Examination
Jun 02, 2025
Response after Non-Final Action
Jul 03, 2025
Non-Final Rejection — §103
Nov 11, 2025
Response Filed
Feb 20, 2026
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

11-12
Expected OA Rounds
31%
Grant Probability
80%
With Interview (+49.2%)
4y 5m
Median Time to Grant
High
PTA Risk
Based on 507 resolved cases by this examiner. Grant probability derived from career allow rate.

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