US 12540950

I'll search for information on US patent 12540950 and any CAFC 2026 docket entries.

The CAFC docket search returned no results. Let me verify further details on the patent and its claims.

Let me check whether the PTAB/IPR relates to this patent and search for the actual claim language and any CAFC activity.

Summary — U.S. Patent No. 12,540,950 B2 (US12540950B2)

Search note

A targeted search for CAFC 2026 dockets referencing this exact patent number returned no results. The bibliographic details below come from the Google Patents record (fetched full text) corroborated by independent search results. I could not locate the granted claim text in the fetched full text or via search, so the claim overview below is necessarily provisional (see caveats).

Bibliographic data

Abstract (verbatim): "The present invention, in some embodiments, generally relates to methods of determining a treatment protocol for and/or a prognosis of a patient's recovery from a brain injury. In some embodiments, the brain injury results from a hypoxic event. In some embodiments, methods are provided for determining a measure of the concentration of tau protein in a patient sample containing or suspected of containing tau protein."

Plain-language overview of independent claims — with uncertainty caveat

⚠️ The claims section was not present in the fetched full patent text, and my searches did not surface the granted claims. The following is reconstructed from the specification's Summary and Detailed Description (which typically mirrors the independent claims in this family) and should be treated as provisional, not authoritative claim text. The likely independent claims track this family's well-known claim structure (sibling U.S. 11,275,092):

1. Ultra-sensitive tau assay method — A method of determining a measure of the concentration of (phosphorylated) tau protein in a patient sample (e.g., blood, serum, or plasma), performed with an assay whose limit of detection is less than about 0.2 pg/mL (in practice ~0.02 pg/mL), i.e., a single-molecule/digital immunoassay far more sensitive than conventional ELISA.
2. Prognosis/treatment determination from blood tau — A method of determining a treatment protocol and/or prognosis for recovery from a brain injury (e.g., hypoxic event such as cardiac arrest) based on a tau concentration measured in a blood/serum/plasma sample by an ultra-sensitive assay.
3. Assay-and-data provision method — A method of performing the assay on a patient's blood-derived sample and providing the resulting data to enable a clinician to determine prognosis/treatment.
4. Serial-sampling method (multi-sample) — Measuring tau concentration in multiple samples taken over at least ~48 hours following the brain injury and basing prognosis/treatment on the measured concentrations.
5. Area-under-the-curve (AUC) method — Measuring tau in serial samples over ≥48 h, computing the AUC of the tau concentration-vs-time curve (for the entire period and/or for the second (delayed) tau peak), and determining prognosis/treatment from that AUC. The specification reports that a secondary-peak AUC cut-point of 500 gave 100% sensitivity / 91% specificity for 6-month outcome.

Litigation / PTAB context (not CAFC)

• Google Patents flags this patent family (Darts-ip family 47009972) as having "first worldwide family litigation filed."
• A related district-court case exists: Fujirebio Diagnostics, Inc. v. Quanterix Corp., No. 1:25-cv-00659 (D. Del.), and an inter partes review, IPR2025-01060 (Fujirebio v. Quanterix), which per one source was discretionarily denied. However, those proceedings expressly concern the sibling patent U.S. 11,275,092 ("Methods of determining a treatment protocol for and/or a prognosis of a patient's recovery from a brain injury"), not US 12,540,950 itself.
• I found no CAFC 2026 docket entry naming US 12,540,950.

Key uncertainties

1. Claims: exact text/numbering of the independent claims of the '950 patent is unverified — I recommend pulling the claim set from USPTO Patent Center (Public Search) or Google Patents claims tab for definitive language.
2. Assignees/inventors on the granted patent are as listed on the Google record but were not independently verified against USPTO assignment records.
3. CAFC docket status could not be confirmed; absence of results does not conclusively prove no proceeding exists.

Based on my searches as of April 26, 2026, I found no litigation specifically involving U.S. Patent No. 12,540,950 (US12540950B2) — i.e., no case naming that patent number in the pleadings with identifiable plaintiffs, defendants, case numbers, filing dates, or statuses.

What I can report:

• Patent status/basics (context): US12540950B2, titled "Methods of assaying phosphorylated tau protein in a sample," is assigned to Quanterix Corporation. Per the Google Patents record, it was filed March 7, 2025 (App. No. 19/073,950), published as US20250208150A1 on June 26, 2025, and granted/issued February 3, 2026. It claims priority back to April 12, 2011 and is part of a large continuation family.
• "Family has litigation" flag (caveat): The Google Patents bibliographic page for US12540950B2 displays a Darts-ip indicator: "Family has litigation — First worldwide family litigation filed" (family ID 47009972). This indicates litigation somewhere in the wider patent family (which contains many earlier-issued Quanterix members), not that US12540950B2 itself is being litigated. I could not retrieve specific case details (parties, court, case number, filing date) from the search results for that family-litigation flag.
• Direct searches for "12540950" + litigation/lawsuit terms: Returned no district court, CAFC, Unified Patents, or PACER records identifying a case against US 12,540,950. Given that the patent only issued in February 2026 (roughly two months before today's date), a filed infringement action specifically naming this just-issued patent would be very unusual but not impossible.

Conclusion: No known litigation specifically involving US Patent 12,540,950 as of April 26, 2026. If you want certainty on the family-level Darts-ip flag, I would recommend checking the Darts-ip family record directly (family ID 47009972) or PACER/Unified Patents for any case that might name this patent later; I could not verify any specific case details through the searches performed.

Proceedings overview

The USPTO Open Data Portal (ODP) returns zero AIA trial proceedings against US 12,540,950 as of the most recent ingest, and independent searching surfaced no IPR/PGR/CBM petitions naming this patent (0 active, 0 instituted, 0 final written decisions, 0 settlements, 0 institution denials). The defensive posture is accordingly a blank slate: the patent issued 2026-02-03 and is currently completely untested before the PTAB — no claim has been canceled or sustained, no estoppel under § 315(e)(2) exists against any petitioner, and the window for a first challenge is still open.

⚠️ Proceeding flag (not on this patent): Searching surfaced IPR2025-01060, Fujirebio Diagnostics, Inc. v. Quanterix Corp. — but that petition challenges U.S. Patent No. 11,275,092, a different patent in the same tau-assay family (the '950 patent's chain traces through the same lineage, e.g., U.S. App. 16/522,237). It is not a proceeding on US 12,540,950. Details and its strategic significance are in the Strategic summary below.

Proceedings against US 12,540,950

None on file

• Type: N/A
• Status: The USPTO ODP API reports no AIA trial proceedings for US 12,540,950 as of the most recent ingest. PTAB E2E/PTACTS likewise shows no case docketed against patent number 12540950.
• Institution decision: None — no petition has been filed.
• Final Written Decision: None issued.
• Appeal: N/A.
• Defensive value: There is no PTAB record either way. That cuts both ways: no claim has been weakened, but equally no petitioner is estopped, and the patent's claims are unproven against the prior art a challenger would deploy (the same body of single-molecule-array / tau-in-blood art already litigated in the Fujirebio matter).

Adjacent proceeding — family context only (not against US 12,540,950)

IPR2025-01060 — Fujirebio Diagnostics, Inc. v. Quanterix Corp. (U.S. Patent No. 11,275,092)

• Type: Inter Partes Review
• Filed: 2025-05-28
• Status: Denied institution (discretionary) — "no trial is instituted"; proceeding terminated.
• Judge panel / decision author: Deputy Director Coke Morgan Stewart (Director-level discretionary denial under 35 U.S.C. § 314(a)).
• Petition grounds: Claims 1 and 6–21 of the '092 patent challenged under 35 U.S.C. § 103 over combinations led by Rissin (single-molecule assay) with Todd, Voorheis, and related art; also a parallel declaratory-judgment suit in D. Del. (1:25-cv-00659-GBW).
• Institution decision: Denied 2025-10-17 (a petitioner fee-refund filing refers to the terminating order as Paper 13, dated 2025-10-07 — docket entries vary on the exact date). The Director granted Quanterix's § 325(d) request under Advanced Bionics, reasoning that the examiner had already considered substantially the same art and arguments during prosecution and that Fujirebio "has not persuasively demonstrated that the Office erred" in crediting rebuttal evidence (e.g., objective indicia of nonobviousness / copying by others). Decision link: PTACTS — Decision Denying Institution.
• Settlement / termination: No settlement — terminated by denial of institution; post-institution fees refunded (refund notice 2025-11-07).
• Appeal: None identified (denial of institution is not appealable).
• Why this matters for a defendant on the '950 patent: The Director's decision shows Quanterix's family prosecution histories are loaded with this exact prior art and that § 325(d) discretionary denial is a live, potent weapon for Quanterix when a petition recycles art the examiner already considered. Case docket: IP Verse — IPR2025-01060. Related D. Del. docket: CourtListener — 1:25-cv-00659. (Third-party litigation summaries report the Delaware case was dismissed via stipulation around 2026-04-10 with Quanterix's infringement claims dismissed with prejudice and Fujirebio's DJ counterclaims without prejudice — treat that as secondary-source context, not verified PACER analysis.)

Strategic summary

Claim status. Every claim of US 12,540,950 is UNTESTED at the PTAB. None are canceled, none have been sustained in an FWD, and no petition has even been filed against this specific patent number. Because the full claim text of the '950 patent is not reproduced in the materials I can verify, I cannot inventory claims 1–N individually — the only accurate statement is that the PTAB record on this patent is empty.

Estoppel landscape. No petitioner has been estopped against US 12,540,950 because estoppel under § 315(e) attaches only to instituted proceedings reaching a final written decision (or to the specific patent at issue in that proceeding). IPR2025-01060 was denied institution, so it created no estoppel even as to the '092 patent, and it has no estoppel effect whatever on the '950 patent. For a defendant facing assertion of the '950 patent today, all prior-art grounds remain available: § 102 and § 103 combinations built on the pre-2011 tau/ultra-sensitive-immunoassay art (e.g., Rissin/Duffy-style SiMoA disclosures, Vandermeeren, Hulstaert, Vanmechelen, INNOTEST hTAU) are still on the table. The practical caveat is the § 325(d) shadow: any petition recycling art the examiner already weighed in this family's prosecution history — and Quanterix will argue the entire Rissin/Duffy/tau canon qualifies — invites discretionary denial, so a petition would need materially new art or a demonstrable examiner error to survive.

Pattern signals. One clear signal: Quanterix is actively enforcing its tau-measurement patent family (public statements threaten infringement risk for anyone measuring tau on non-Quanterix platforms) and has shown it will fight at the PTAB — it filed a discretionary-denial request in IPR2025-01060 and won a Director-level denial within roughly five months. The '950 patent — "Methods of assaying phosphorylated tau protein in a sample," naming Wilson, Zetterberg, Blennow, and Randall, assigned to Quanterix — is a continuation that issued 2026-02-03 and is listed on Google Patents with a "Family has litigation" marker (see Darts-ip family 47009972). No defensive aggregator (e.g., Unified Patents) appears in the chain to date.

Recommended next steps

1. Confirm the empty docket yourself before relying on it: check PTAB E2E / PTACTS and the USPTO ODP API for "12540950." The record can change quickly.
2. Know the timing traps. The patent granted 2026-02-03. A PGR is almost certainly unavailable (the family claims priority to pre-AIA provisional applications filed 2011-04-12, and PGR is limited to AIA-eligible patents), making IPR the only AIA vehicle. If Quanterix serves a complaint on your client, the § 315(b) one-year bar clock starts on service — an IPR petition must be on file within one year of service, and earlier is better because it maximizes the chance of a stay.
3. If you petition, bring new art or a real error argument. The IPR2025-01060 decision is a roadmap: the Director denied institution because the petition re-ran art and arguments the examiner already considered, and Quanterix has deep prosecution histories across this family (14/111,326 → 15/269,142 → 16/522,237 → 17/674,968 → 19/073,950) full of the same references. A § 325(d)-proof petition must center on prior art or reasoning materially different from what the examiner addressed.
4. Track the family, not just the patent. Quanterix's enforcement posture is defined by the broader tau/Simoa portfolio (including 11,275,092), and the D. Del. litigation between Fujirebio and Quanterix (1:25-cv-00659-GBW) has already been through motion practice on claim scope and patent-eligibility theories. Monitor that docket and the '092 patent's family for developments that will foreshadow arguments against the '950 patent.
5. No FWD exists to cite — there is no PTAB disposition of any claim of the '950 patent, so no claim-level invalidity ruling is available to leverage. If a demand letter cites the '950 patent, the honest near-term posture is that validity is entirely untested and the defendant's leverage comes from the strength of the prior art, not from any PTAB outcome.

Inventors

All four inventors are named on US12540950B2. Employers at the time of filing are determinable from the record:

• David Wilson — Quanterix Corporation (Boxborough, MA). Quanterix employee and company scientist at the priority date (Quanterix announced this cardiac-arrest/tau work April 12, 2011, the same day as the first provisional filing).
• Jeffrey D. Randall — Quanterix Corporation (Canton, MA). Quanterix employee; appears throughout Quanterix's digital-ELISA (Simoa) patent families and publications.
• John Henrik Zetterberg — University of Gothenburg / Sahlgrenska University Hospital, Mölndal, Sweden (academic collaborator; residence listed as Mölndal, SE).
• Kaj Blennow — University of Gothenburg / Sahlgrenska University Hospital, Sweden (academic collaborator; residence listed as Kungsbacka, SE).

Pattern note: No unusual pattern. This is a conventional industry–academia collaboration: two Quanterix staff scientists (Wilson, Randall) plus two Swedish academic neurologists (Zetterberg, Blennow), with rights assigned to the commercial party (Quanterix). The Zetterberg/Blennow pair appears on a long series of Quanterix neuro-biomarker patents through the present day, so there is no "inventors depart → portfolio fire-sale" signature.

Original assignee

• Quanterix Corporation, Billerica, MA — named as applicant/original assignee on the patent (agent of record: Wolf, Greenfield & Sacks, P.C.).
• Line of business: Digital immunoassay ("Simoa") instruments and reagents — single-molecule ELISA platforms (HD-X, SR-X) plus neurology biomarker assays, including phosphorylated-tau (p-tau 181/217), tau, GFAP, NfL and UCH-L1 products.
• Product embodiment: Yes — the company commercializes Simoa-based tau/p-tau assays (the claimed sub-0.2 pg/mL digital tau assay class), and the claimed methods are core to its neurology product line.
• Current status: Operating. Quanterix Corporation is a publicly traded company (NASDAQ: QTRX); no bankruptcy, dissolution or acquisition found.

Assignment timeline

No recorded assignments were located for US12540950B2. Direct searches of assignment records, Google Patents legal events, and family-level databases surfaced no conveyance entries — no Assignment, Security Agreement, Merger, Change of Name, or License — for this patent number. The Google Patents record for the patent shows only procedural events (2025 filing by Quanterix; 2025 publication; 2026 grant; status "Active"), consistent with a patent that has remained with its original assignee through a purely internal continuation chain:

• Provisional 61/474,315 (2011-04-12) and 61/524,693 (2011-08-17) → PCT/US2012/033343 (2012-04-12) → US 14/111,326 (2014) → 15/269,142 (2016) → 16/522,237 (2019) → 17/674,968 (2022) → 19/073,950 (2025-03-07) → granted 2026-02-03.

Every application in the chain was filed by Quanterix Corporation itself, and no third-party assignee appears anywhere in the chain. Caveat: I could not query the USPTO Assignment Center (assignmentcenter.uspto.gov) directly to retrieve the underlying reel/frame index; the finding of "no records" is based on the absence of any assignment event in the bibliographic/legal-event record and the absence of any transfer in secondary indexes, not on a verified zero-hit Assignment Center query. The absence of post-issuance assignments is itself the meaningful finding: the original assignee, Quanterix Corporation, still owns the patent. No reel/frame numbers are cited because none could be verified without fabrication.

Timeline diagram

timeline
    title Ownership of US 12540950
    2011 : Priority filed
    2012 : PCT filed by Quanterix
    2014 : US national stage filed
    2016 : Continuation filed
    2019 : Continuation filed
    2022 : Continuation filed
    2025 : Final continuation filed
         : Application published
    2026 : Patent granted
         : Ownership stays Quanterix

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No transfer of any kind was found; ownership never left the operating company (Quanterix Corporation), so no licensing-only LLC ever entered the chain.
2. Known asserter in the chain — not present. No assignee or prior assignee matches any public NPE list (Acacia, Marathon, IV, Conversant, Vringo, etc.). The sole owner, Quanterix, is a NASDAQ-listed diagnostics manufacturer, not a patent-assertion entity.
3. Repeat correspondent across the chain — not present / not applicable. The prosecuting firm is Wolf, Greenfield & Sacks, P.C. (Boston), Quanterix's long-time prosecution counsel. It appears once (as agent of record) and is a mainstream patent firm doing operating-company prosecution; a single appearance is not a finding, and no assignment correspondents exist to compare.
4. Cascading transfers — not present. No consecutive LLC-to-LLC assignments exist; there is no assignment chain at all.
5. Pre-litigation transfer — not present. No assignment exists, and per the litigation summary no infringement suit naming US12540950B2 has been identified (the patent issued only 2026-02-03).
6. Bankruptcy fire-sale — not present. Quanterix is not in bankruptcy and has not sold patents in any insolvency proceeding.
7. Privateering — not present. No transfer of the patent to any third-party enforcer, and no SEC/8-K or press evidence of Quanterix funding an NPE to assert on its behalf was found.
8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN; it terminates at the original operating assignee.

Verdict

Insufficient data — no recorded assignments (only the original assignment to the operating assignee) and no NPE signals of any kind.

Justification: every link of the priority chain from 2011 through grant in 2026 was filed by and remained with Quanterix Corporation, a public operating company (NASDAQ: QTRX) that commercializes Simoa tau/p-tau assays; no reel/frame conveyance could be identified, no litigation naming the patent was found, and none of the eight NPE signals is present. The record therefore shows an operating-company-held patent with no assertion history — but because I could not verify a zero-hit result in the USPTO Assignment Center directly (and thus cannot fully rule out an unindexed or very recent filing), "insufficient data" rather than a firmer classification is the honest call.

Verify at: https://assignmentcenter.uspto.gov/ (search patent no. 12540950) or the legacy index https://assignment.uspto.gov/patent/index.html.

The initial searches surfaced important context: the sibling patent U.S. 11,275,092 B2 (same family) has been through IPR petitions and district-court litigation, and several references (e.g., "Rissin," "Todd," "Voorheis," "Duffy," "Wunderlich/Mortberg," "Ding") were discussed there. However, I still need the actual "References Cited" list printed on the face of US 12,540,950 itself. Let me search more specifically.

I need to locate the actual "References Cited" (patent and non-patent) printed on the face of US 12,540,950 B2. Let me try additional targeted searches, including USPTO and Google Patents citation-tab content.

Search summary and critical caveat on source data

Before providing the prior-art analysis, I need to flag a data-availability problem that materially limits the precision of what follows:

1. The Google Patents full-text record for US 12,540,950 B2 (fetched 2026-09-07 in the working file) is truncated. It ends mid-sentence in the Detailed Description ("a binding surface having affinity for at least one type of biomarker. For example, the capture objects may comprise a plurality of beads comprising a plurality of capture components (e.g., an antibody having specific affini…"). The Claims section and the "References Cited" section (patent citations + non-patent citations) are not present in the authoritative text available to me.
2. Targeted searches for the face-of-patent citation list of "12540950" specifically returned no page enumerating its examiner-cited references (several queries returned empty result sets, and a final search was cut off by a step limit).
3. What my searches did reliably surface is a trove of prosecution/litigation documents for the immediate parent in the same chain, U.S. 11,275,092 B2 (D. Del. 1:25-cv-00659; IPR2025-01060; PTAB petition-decision documents), which identify the prior art the Examiner actually applied/considered for the shared specification and claim scope. Because US 12,540,950 is a continuation of that chain (17/674,968 → 16/522,237 → 15/269,142 → 14/111,326 → PCT/US2012/033343) claiming the same April 12, 2011 priority, its citation list will substantially overlap — but I cannot certify that any given reference is printed on the '950 face without the USPTO/Google citation tab.

Accordingly, the analysis below distinguishes three tiers of verifiability: (A) references verifiably cited within the '950 specification text itself; (B) references verifiably considered by the Examiner for the identical-disclosure parent '092 (from PTAB/court filings); (C) an explicit statement of what could not be verified. The granted claims of the '950 patent are likewise unverified (see prior sections), so all claim mapping is provisional, keyed to the reconstructed claim themes and to the '950 title's focus on assaying phosphorylated tau (p-tau; the shared specification names p-tau-181 and p-tau-231).

A. References verifiably cited within the US 12,540,950 B2 specification (incorporated-by-reference/cited in text)

These appear in the authoritative fetched text and are the only "citations for 12540950" I can verify directly. All are single-molecule / digital immunoassay disclosures (the assay format the claims require) or clinical-staging scales cited in the specification.

A1. Walt et al. U.S. Patent Application Publications (filed Feb. 16, 2007; published 2007)

• US 2007/0259448 A1 — "Methods and arrays for target analyte detection and determination of target analyte concentration in solution" (Ser. No. 11/707,385)
• US 2007/0259385 A1 — "Methods and arrays for detecting cells and cellular components in small defined volumes" (Ser. No. 11/707,383)
• US 2007/0259381 A1 — "Methods and arrays for target analyte detection and determination of reaction components that affect a reaction" (Ser. No. 11/707,384)
• WO 2009/029073 A2 (PCT/US2007/019184, filed Aug. 30, 2007) — "Methods of determining the concentration of an analyte in solution"

Description: Foundational single-molecule-array (SMA) disclosures from the Tufts group: capture of analyte on beads bearing capture antibodies, isolation of individual beads in femtoliter-scale reaction vessels (e.g., etched fiber-optic microwell arrays), enzyme-labeled sandwich complexes, and digital "count of occupied wells" readout with Poisson statistics to derive concentration. Dates: published 2007–2009, i.e., well before the April 12, 2011 priority date — genuine § 102 art.
Provisional § 102/103 analysis: Against any '950 claim drawn to the ultra-sensitive (LOD < 0.2 pg/mL) platform mechanics (bead capture → femtoliter well isolation → digital counting of single immunocomplexes), these references disclose substantially every platform step. They do not disclose tau/p-tau as the analyte, so they would not alone anticipate a claim limited to assaying phosphorylated tau; they are strongest as 103 combinable art (with A4/A5 below) and, for a generic "assay of a biomarker in a sample" claim lacking tau limitation, could be asserted under pre-AIA § 102(a)/(e)/(g) or AIA § 102(a)(1)/(2) depending on the effective filing date of the specific claim.

A2. Duffy et al. Quanterix ultra-sensitive detection publications (published 2010–2011)

• US 2010/0075862 A1 (Ser. No. 12/236,484, filed Sep. 23, 2008) — "High sensitivity determination of the concentration of analyte molecules or particles in a fluid sample"
• US 2010/00754072 A1 (12/236,486), US 2010/0075439 A1 (12/236,488), US 2010/0075355 A1 (12/236,490) (all filed Sep. 23, 2008)
• WO 2010/039179 (PCT/US2009/005248, filed Sep. 22, 2009) — "Ultra-sensitive detection of molecules or enzymes"
• US 2011/0212848 A1 (Ser. No. 12/731,130, filed Mar. 24, 2010) and WO 2011/109364 (PCT/US2011/026645, filed Mar. 1, 2011) — "Ultra-sensitive detection of molecules or particles using beads or other capture objects"
• US 2011/0212462 A1 (12/731,135) and WO 2011/109372 (PCT/US2011/026657) — "Ultra-sensitive detection of molecules using dual detection methods"
• US 2011/0212537 A1 (12/731,136) and WO 2011/109379 (PCT/US2011/026665) — "Methods and systems for extending dynamic range…"
• US 2011/0245097 A1 (Ser. No. 13/037,987, filed Mar. 1, 2011, Rissin et al.) — dynamic-range extension
• US 2011-0212848's sibling and the Fournier systems application (Ser. No. 13/035,472, filed Feb. 25, 2011)

Description: These are the commercial "Simoa®" precursors describing the exact assay architecture used in the '950 working examples: 2.7 µm carboxyl paramagnetic beads, anti-analyte capture antibody, biotinylated detector, streptavidin-β-galactosidase label, 50-femtoliter etched fiber-optic microwell arrays, CCD imaging, digital (Poisson) counting at low occupancy transitioning to analog intensity readout, and reported fM–aM sensitivities (LOD ~0.02 pg/mL for tau in Example 2 of the shared specification).
Dates/criticality caveat: The 2008-filed, 2010-published Duffy publications (A2 first block) are prior art. But several 2011 publications (e.g., filed Mar. 2011) are co-pending with the Apr. 12, 2011 priority date, and the '092/'950 family's own priority application was filed April 12, 2011 — so these are not § 102 prior art against claims fully entitled to the 2011 date (they are 103-combinable at best and arguably not even that if the '950 claims are limited to p-tau, which they do not mention). The PTAB decision documents I retrieved confirm the Examiner already confronted exactly this art (referred to there as "Rissin" and "Quanterix 2010a") for the identical disclosure in the '092 patent and allowed the claims over it.

A3. Legacy array/well-array patents cited in the specification

US 5,700,637; US 5,807,522; US 5,445,934; US 6,406,845; US 6,482,593 (issued 1995–2002); WO 95/25116; WO 95/35505; PCT/US98/09163. Description: generic array fabrication (photolithography, spotting, fiber-optic well arrays). § 102 relevance: low — these go to well-array hardware alone and would not anticipate the assay/prognosis claims.

A4. Non-patent literature cited in the specification (clinical outcome scales)

• Teasdale G, Jennett B. "Assessment of coma and impaired consciousness." Lancet 2(7872):81–84 (1974) — Glasgow Coma Scale (cited for CPC/GCS outcome criteria).
• T.S. Richmond, "Cerebral Resuscitation After Global Brain Ischemia: Linking Research to Practice," AACN Clinical Issues, May 1997, Vol. 8, No. 2 — hypoxic-ischemic brain injury management/treatment options (hypothermia, antioxidants, steroids).
• Dekaban A.S., Robinson C.E., "Application of a new rating scale of brain dysfunction…" Bull. Clin. Neurosci. 49:82–92 (1984).
• § 102 relevance: negligible against assay claims; relevant only to claims tying outcome classification (CPC 1–2 "good" vs. 3–5 "poor") to tau levels, and even then only as background for the known outcome scales, not the claimed assay steps.

B. Prior art verified as Examiner-considered/applied for the identical-disclosure parent '092 (highly likely reflected in the '950 file history — flagged as not face-verified for '950)

From the PTAB decision documents and Fujirebio v. Quanterix filings (both expressly discussing the shared specification and its Examiner's citations), the following were the operative references. These are the most substantive anticipation candidates for the claimed subject matter because they combine (i) the SMA platform with (ii) tau as the analyte and (iii) brain-injury clinical correlation:

What these filings establish about the Examiner's own conclusion (relevant to anticipation): The PTAB decision I retrieved states that the '092 Examiner "applied the asserted prior art or substantially the same prior art during examination," considered Rissin, Voorheis, Duffy, Wunderlich/Mörtberg, and Ding, and nonetheless allowed the claims — finding that no pre-2011 reference showed blood tau measured at the claimed sub-0.2 pg/mL sensitivity or suggested using Simoa to detect tau. That same record (Ex. 1001's face listing, per the decision) includes the Simoa patent family (US 8,236,574; US 8,415,171; US 8,460,878; US 8,460,879; US 8,492,098) as cited art on the '092 face — all of which are 2010–2013 publications and, to the extent they precede April 12, 2011, are the same platform art as A2.

C. Claim-by-claim anticipation mapping (provisional — claims unverified)

Given that the '950 granted claims could not be retrieved, the mapping below uses the five reconstructed claim themes from the earlier section, now adjusted for the '950 title's emphasis on phosphorylated tau (p-tau-181 / p-tau-231 are expressly listed in the shared specification's biomarker passage):

1. Ultra-sensitive p-tau assay claim (LOD < 0.2 pg/mL, digital/SMA format): Rissin/A2 discloses every platform element but no p-tau analyte → does not anticipate alone; Todd (if it teaches tau but at conventional sensitivity) → does not anticipate the LOD limitation; no single located reference discloses a sub-0.2 pg/mL phospho-tau-specific sandwich assay pre-2011 → no § 102 anticipation on the available record; 103 combinations (Rissin + Todd; Duffy + Wunderlich/Mörtberg) are the realistic attacks, and the Examiner already rejected those for the '092 claims.
2. Blood/serum/plasma p-tau prognosis claims: Mörtberg/Wunderlich-type art teaches blood tau after cardiac arrest/TBI with outcome correlation but not p-tau and not at the claimed sensitivity → no § 102 anticipation; the sub-0.2 pg/mL LOD + p-tau limitation is the crux the Examiner found unmet.
3. Serial-sampling and AUC/second-peak prognosis claims: No located reference discloses the bimodal serum-tau kinetic profile with a prognostic "second peak" (AUC cut-point ~500) — that was the inventors' own discovery in the shared specification → no § 102 anticipation found.
4. Data-provision/assay-service claim: method-of-treatment/prognosis based on measured p-tau; same analysis as (2).

Bottom line on § 102: On everything verifiable, no single reference anticipates the combination of (a) a sub-0.2 pg/mL-LOD digital immunoassay, (b) directed to (phosphorylated) tau, (c) in blood/serum/plasma, (d) after a hypoxic brain injury, with (e) the bimodal/AUC prognostic correlation. The nearest single-reference candidates are Todd (tau + SMA) and the platform art of Rissin/Duffy/Walt — and the PTAB record confirms the Examiner already allowed the identical-disclosure claims over precisely those references.

D. Unverified items — where to go for certainty

• Face-of-patent "References Cited" list of US 12,540,950 B2: not retrievable from the truncated Google record or via search; pull USPTO Patent Center (Application 19/073,950) or the Google Patents "Citations" tab for the definitive list.
• Granted claims of US 12,540,950: not in the fetched text; all claim mapping above is provisional.
• § 102 law applicable: priority chain runs to Apr. 12, 2011 (pre-AIA), so if all claims are entitled to that date, pre-AIA § 102(a)–(g) governs; a claim not entitled to the 2011 date would be assessed under AIA § 102(a)(1)/(2). I could not confirm which regime governs each claim without the file history.
• I found no CAFC docket naming US 12,540,950 (consistent with the earlier litigation summary), so no court-construed claim chart for the '950 claims exists yet to anchor anticipation analysis.

Scope note and methodology caveat

Before the analysis, three honesty flags:

1. No "Prior Art" section was actually present in the materials provided to me in this session. The patent text you supplied contains the specification but the claims and the front-page "References Cited" list were not included, and I could not retrieve the granted claim text of US 12,540,950 B2 from any source. I therefore analyze obviousness against the representative claim scope reconstructed from the specification (ultra-sensitive tau assay with LOD < ~0.2 pg/mL in blood/serum/plasma; prognosis/treatment determination after brain injury/hypoxic event; serial sampling ≥ 48 h; AUC of the full curve and/or the second tau peak), with the caveat that claim-by-claim mapping is provisional.
2. My search results from the ongoing Fujirebio Diagnostics v. Quanterix (D. Del. 1:25-cv-00659) and IPR2025-01060 records are the richest source of the actual prior-art combos that were used against this patent family during prosecution, and per your operating rules I treat those search results as current ground truth where they bear on the art.
3. The combination analysis below is the best challenger's case; I include the strongest counter-evidence (which the Examiner and PTAB credited in the sibling '092 patent) so the analysis is balanced.

Legal framework

Under 35 U.S.C. § 103 (pre-AIA rules apply, given the April 12, 2011 priority date), a claim is unpatentable if the differences between the claimed subject matter and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art (PHOSITA). The Graham factors apply: (1) scope and content of the prior art; (2) differences between the prior art and the claims; (3) level of ordinary skill; (4) secondary considerations. Under KSR Int'l Co. v. Teleflex, the analysis is flexible — a PHOSITA may combine known elements by known methods when there is a design need or market pressure and a reasonable expectation of success.

The PHOSITA here is a team: an analytical biochemist/immunoassay scientist experienced in sandwich immunoassay development and single-molecule/digital detection, plus a clinician-scientist experienced in neurocritical care, brain-injury biomarker validation, and biostatistics (AUC/ROC, CPC outcome measures).

Principal prior-art references available before the April 12, 2011 priority date

Post-priority references (NOT § 103 art for claims entitled to the 4/12/2011 date, but confirmatory of the trajectory): Mörtberg et al., Acta Anaesthesiol. Scand. 55:1132–1138 (epub Sept. 8, 2011 — late plasma tau elevation at 48–96 h predicted CPC 3–5 outcome, 71% sens/93% spec at 96 h); Randall et al., Resuscitation 84:351–356 (epub Aug. 9, 2012 — the inventors' own published version of patent Example 1); Ding et al. (2021 meta-analysis of blood tau assays).

Combination 1 — Ultra-sensitive assay claims (e.g., "assay with LOD < ~0.2 pg/mL for tau in a blood-derived sample")

Proposed combination: Rissin 2010 / Duffy '407 + Wunderlich 2006 (and/or Liliang 2010).

Element mapping (representative):

• Single-molecule/digital immunoassay steps — Rissin 2010 and Duffy '407 disclose every step: antibody-coated paramagnetic capture beads; sandwich immunocomplex with enzyme-labeled detector; isolation of single beads in femtoliter reaction wells; fluorescence imaging/counting of active wells; Poisson-statistics conversion; analog calibration to extend dynamic range.
• LOD less than ~0.2 pg/mL — Rissin reports detection at 14 fg/mL (0.4 fM) and routine sub-picomolar serum detection; a PHOSITA would understand the platform LOD is ~3–4 orders of magnitude below conventional ELISA — comfortably inside the claimed bound (the patent's own Example 2 is the same assay adapted to tau, reporting LOD 0.02 pg/mL).
• Tau as the analyte, in blood/serum/plasma — supplied by Wunderlich (tau detectable in serum after stroke) and Liliang (tau in serum after TBI). Tau was a known analyte; its amino-acid sequence, isoforms, and commercial antibodies (e.g., the anti-tau antibodies the patent itself uses from Covance/Pierce) were all publicly available.

Motivation and reasonable expectation of success: This is essentially the Examiner's own rejection rationale in the sibling family (Ex. 1002 at 496–98): "one of ordinary skill in the art at the time of the invention would have found it obvious that the method of Duffy could be used to detect and quantify tau … in a blood/serum/plasma sample of a patient recovering from a brain injury." The motivation is explicit in Rissin's stated purpose — digital ELISA exists precisely to "detect low-abundance proteins in blood" and "clinically relevant proteins in serum at concentrations much lower than conventional ELISA." The conventional art documented the unmet need: Ost 2006 could not detect serum tau at all; Wunderlich's tau values were at the noise floor of his 60 pg/mL ELISA; Liliang's outcome groups overlapped enormously (±473 pg/mL SDs). A PHOSITA wanting a reliable blood-based tau measurement had (i) a known biomarker (tau), (ii) a known reason it was hard to measure in blood (low pg/mL abundance), and (iii) a just-published, validated assay purpose-built to close exactly that sensitivity gap. Substituting the anti-tau capture/detector antibodies for anti-PSA antibodies is a routine reagent swap with a strong expectation of success — sandwich immunoassay architecture is analyte-independent.

Weaknesses of the challenger's case: The Examiner ultimately allowed claims over this combination, crediting evidence that (a) the prior blood-tau measurements were noisy/unreliable (Wunderlich data "buried in noise"; Liliang's enormous SDs; Quanterix 2010a's own conventional-ELISA control showing 60–80 pg/mL in disease-free patients — suggesting prior "blood tau" readings were nonspecific), and (b) before this disclosure there was skepticism that blood tau was measurable at analytically valid levels. If the granted '950 claims are limited to phosphorylated tau (per the title), the gap is larger: the prior art above measured total tau, and p-tau-specific capture in blood at sub-pg/mL is not taught by Wunderlich/Liliang/Rissin.

Combination 2 — Prognosis/treatment claims (single or serial samples)

Proposed combination: Combination 1 + Wunderlich 2006 and/or Liliang 2010 and/or Mörtberg 2010 thesis.

Element mapping: The remaining limitation — "determining a prognosis of recovery from brain injury and/or a method of treatment based at least in part on the measured tau concentration" — was already in the art:

• Wunderlich: serum tau within 3–12 h after stroke related to neurobehavioral outcome;
• Liliang 2010: serum tau levels "may serve as indicators for the prediction of outcome following severe TBI" (explicitly linking measured blood tau to outcome);
• Mörtberg 2010 (and the same group's 2011 Acta paper, for any claim not entitled to the earliest priority date): late plasma tau elevation after cardiac arrest predicted poor CPC outcome (71% sens/93% spec at 96 h), with serial sampling at 2–96 h and CPC scoring at 6 months — the same outcome instrument, sampling window, and injury type (hypoxic brain injury from cardiac arrest) as the patent.

Motivation: Once tau is reliably measurable in blood (Combination 1), applying it to the well-established clinical question "does biomarker X predict neurological outcome after cardiac arrest/TBI?" is the obvious next step — biomarker-outcome correlation after brain injury was routine (NSE, S100B were already used this way; Mörtberg and Liliang explicitly did it with tau). A clinician-scientist would be directly motivated to validate serum tau against CPC outcome in the cardiac-arrest population.

Weaknesses: The Examiner found this gap was filled by Quanterix 2010a (tau + brain-injury monitoring suggestion) plus Wunderlich/Mörtberg — and still allowed claims, on secondary considerations (field skepticism, no analytically reliable prior blood-tau quantification at the claimed levels, post-publication "paradigm shift"). The strongest counter is that prior "prognosis" results were built on analytically unreliable measurements, so the claimed invention's contribution was establishing that reliable sub-pg/mL quantification was possible — an enablement/skepticism argument that goes to obviousness only through secondary considerations, not through the references themselves.

Combination 3 — Serial-sampling / AUC-of-second-peak claims

Proposed combination: Combination 1 + Wunderlich/Liliang/Mörtberg + routine clinical biostatistics (serial biomarker AUC and ROC analysis).

Element mapping:

• Plurality of samples over ≥ 48 h — Mörtberg (2010 thesis; 2011 Acta paper) took serial samples at 2, 6, 12, 24, 48, 96 h after cardiac arrest; Wunderlich sampled at 3, 6, 12 h.
• Second/delayed tau peak — Mörtberg's central finding was that late tau (48 h and 96 h) separated good from poor outcome while early values did not — i.e., the "delayed elevation after 24–48 h" phenomenon the '950 claims capture is directly foreshadowed. The patent's own specification concedes the second peak is the prognostically decisive one, which is precisely what Mörtberg observed (late increase associated with worse outcome).
• AUC of concentration-vs-time (full period and/or second peak); prognosis from AUC — Computing AUC from serial concentration-time data is a standard pharmacometric/statistical tool (the specification itself used GraphPad Prism, off-the-shelf software), and ROC analysis with AUC cut-points (the patent's own Fig. 3 and 100%/91% statistics) was a routine method for evaluating biomarker classifiers in the neurocritical-care literature. Once serial tau data showed a bimodal shape, computing the AUC of the second phase and thresholding it against outcome is the textbook way to convert serial biomarker data into a classifier.

Motivation: A PHOSITA who has observed (as Mörtberg did) that late tau elevation tracks poor outcome would naturally integrate the serial measurements (AUC) rather than rely on single time points — AUC is the default method for summarizing "total biomarker burden" and had been used for NSE/S100B in the same cardiac-arrest literature. There is a reasonable expectation that a summary measure of total tau exposure over 5 days would outperform any single time point.

Weaknesses (strongest for the patentee): The specific claim elements — AUC computed over a second peak specifically, with a defined baseline at the second peak's onset, and a 500 AUC-unit cut-point giving 100% sensitivity/91% specificity — are empirical findings not expressly taught in any located reference. Mörtberg taught late single-time-point elevations, not second-peak AUC analysis. A challenger would need to argue that isolating the second phase for analysis was an obvious design choice once bimodality was observed — plausible under KSR, but the quantitative correlation itself (and its exact cut-points) is the kind of "unexpected result" a patentee would use to rebut obviousness, and no located reference reports second-peak AUC analysis for tau.

Countervailing considerations (what the Examiner/PTAB already credited)

For intellectual honesty, note that this exact obviousness architecture was already litigated at the administrative level for the sibling '092 patent (U.S. 11,275,092), with results favoring Quanterix:

1. The Examiner rejected — and then allowed — claims over Duffy + Quanterix 2010a ± Wunderlich/Mörtberg, ultimately accepting patentee's evidence that (a) prior blood-tau measurements were analytically unreliable or nonspecific (Ost: undetectable in serum; Wunderlich: near/at assay LOD; Liliang: overlapping SDs of hundreds of pg/mL; Quanterix 2010a's conventional-ELISA controls at 60–80 pg/mL in healthy patients); (b) a 2021 meta-analysis (Ding) showed essentially all reliable blood-tau measurements post-dated the family's WO 2012/142301 publication and used the claimed Simoa technique; and (c) there was field skepticism and a subsequent "paradigm shift" to blood tau (Teunissen 2020 commentary; commercial success evidence).
2. The PTAB denied institution of IPR2025-01060 (Fujirebio's petition relying on Rissin + Todd/Voorheis), holding under Advanced Bionics that the petition's grounds were cumulative of art the Examiner had already applied and that the petitioner failed to show no reasonable examiner could have allowed the claims. That denial is procedural (not a merits finding of patentability), but it signals that substantially the same combinations argued here did not, in the PTAB's view, present a materially stronger case than what the Examiner already weighed.

Those outcomes concern the sibling '092 patent, not US 12,540,950 itself, and the '950's title ("Methods of assaying phosphorylated tau protein in a sample") suggests its granted claims may be narrower/different (e.g., p-tau-specific antibody pairs and sub-pg/mL p-tau quantification), which would strengthen the patent against Combinations 1–3 above, since none of the located prior art measures phosphorylated tau in blood.

Bottom line

• The strongest challenger combination is: Rissin 2010 (Nat. Biotechnol.) and/or Duffy '407 (US 2010/0075407 A1), in view of Wunderlich 2006 and/or Liliang 2010 (tau in blood after brain injury), optionally further in view of the Mörtberg 2010 thesis (serial plasma tau after cardiac arrest, CPC outcome, late-elevation prediction). A PHOSITA's motivation is textbook: a known low-abundance biomarker (tau) with a documented clinical rationale (brain-injury outcome prediction) meets a just-published assay platform whose express purpose was detecting low-abundance serum proteins below conventional-ELISA limits. This mirrors the Examiner's own § 103 rejections in the family.
• The hardest claims to attack are those tied to (i) phosphorylated tau quantification (untouched by the located total-tau art), and (ii) the second-peak AUC methodology with its specific cut-points (no located reference teaches second-peak AUC analysis for tau; the patentee will argue unexpected results/empirical discovery).
• The most important practical caveat: because the granted claim text of US 12,540,950 B2 could not be retrieved during this analysis, the element-by-element mapping above is provisional; confirm the independent claim language from USPTO Patent Center before relying on any of these combinations in a formal validity opinion.

Key references for citation: Rissin et al., Nat. Biotechnol. 28:595–599 (2010), doi:10.1038/nbt.1641; US 2010/0075407 A1 (Duffy); Wunderlich et al., Stroke (2006); Liliang et al., J. Surg. Res. 160:302–307 (2010); Ost et al., Neurology 67:1600–1604 (2006); Mörtberg et al., Acta Anaesthesiol. Scand. 55:1132–1138 (2011), doi:10.1111/j.1399-6576.2011.02505.x (post-priority, confirmatory only); Randall et al., Resuscitation 84:351–356 (2013), doi:10.1016/j.resuscitation.2012.07.027 (inventors' own post-priority publication); Examiner's rejection rationale and PTAB Advanced Bionics denial in IPR2025-01060 / Ex. 1002 (USPTO PTACTS docket 1557963; D. Del. 1:25-cv-00659 record, CourtListener docket 70398011).