Research report
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dossier is synthesized from — generated on a plan and a cadence, one topic per file.
A report carries no confidence tags. Its bracketed markers say who might have
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Corroborator, like everything else.
Section reimbursement · Version 2026-09-01 · Cadence quarterly · Evidence class 1 registry · Sources 9 · Supersedes none
Domain: potassium-monitoring-ckd · Scope: HCPCS Level II codes and payer coverage policy only. CPT descriptor text is AMA-licensed and is never reproduced anywhere in this report; the analyte tests this domain cares about (serum/point-of-care potassium and creatinine) bill under CPT (HCPCS Level I) codes, which are named at most by number where unavoidable and never with their descriptor. Public primary sources reachable by this repo's typed connectors, WebSearch and WebFetch this pass. Excludes any finding this pass could not itself retrieve: www.cms.gov and the ecfr.gov web interface each returned HTTP 403 or a bot-mitigation redirect on every direct-fetch attempt this pass (the CMS Medicare Coverage Database's own LCD page, the CMS NCD manual PDF, a CMS fee-schedule fact sheet, and the eCFR web UI for 42 CFR 409.46), and the FDA CLIA-waived-analyte search page returned HTTP 404 on two attempts, so no finding from any of those pages appears below. This repo's typed `hcpcs`, `payment`, `coverage` and `procedures` connectors each require a local CMS cache file that is absent on this machine, so no lookup from them appears below either. Non-US jurisdictions are out of scope; no connector in this repo queries one.
Sourcing: rests on five sections of 42 CFR and two Federal Register documents confirmed live this pass via this repo's typed `regulation` and `policy` connectors, one CMS HCPCS Level II master file downloaded and searched directly by this pass rather than sampled through a search engine, and one HHS administrative-appeal decision confirming one Local Coverage Determination's identity and contractor.
No HCPCS Level II code exists for a potassium or creatinine laboratory test itself: an exhaustive text search of CMS's own January 2026 HCPCS Level II Alpha-Numeric master file, downloaded and searched directly by this pass, finds "potassium" only in injectable-drug and IV-fluid codes and "creatinine" only in two retired or narrow quality-measure documentation codes, never in a code that pays for performing the test [1]. The test itself bills under a CPT (HCPCS Level I) code, which is AMA-licensed and outside this report's scope, and its Medicare payment rides on the Clinical Laboratory Fee Schedule mechanism at 42 CFR Part 414 Subpart G — the same weighted-median, private-payor-rate-based system that prices any other clinical diagnostic laboratory test [2][3]. For a home-health-delivered variant, federal regulation is direct and unfavorable to separate payment: 42 CFR 409.46(e) defines "remote patient monitoring" as the collection of physiologic data digitally stored or transmitted to the home health agency, and states plainly that "the costs of any equipment, set-up, and service related to the technology are allowable only as administrative costs" — not separately billable [4]. CMS's proposed RAPID coverage pathway would not shortcut either route for a potassium-measuring (in-vitro-diagnostic) device: the notice itself says CMS expects IVD coverage determinations to continue through the Medicare Administrative Contractors' existing processes [5]. And a HCPCS code this domain's own dossier had flagged, from secondary sources, as remote-monitoring-adjacent — G0511 — is discontinued: the master file's own record carries Action Code "D" and a Termination Date of 2025-12-31 [1].
_Baseline (v1). No prior version; this establishes the starting point for future diffs._
This pass downloaded CMS's own January 2026 HCPCS Level II Alpha-Numeric Coding System file directly from cms.gov/files/zip/january-2026-alpha-numeric-hcpcs-file.zip (confirmed live, 2,519,574 bytes, filename hcpc2026_jan_anweb_01122026.zip) and searched its full text for "potassium" and "creatinine" [1]. Every "potassium" match is an injectable drug or IV-fluid code — penicillin G potassium injection, potassium chloride injection, pemetrexed dipotassium injection, and several parenteral/enteral electrolyte-replacement codes — plus one non-covered outpatient IV-insulin-titration protocol code (Coverage Code "M", "Non-covered by Medicare" in the master file's own field) that lists arterial, venous or capillary glucose and potassium concentration only as measurements that may guide dosing, not as a billable test in its own right. Every "creatinine" match is a quality-measure documentation code from the PQRS/MIPS era — one set (added 2012, Termination Date 2014-12-31 in the file) records whether a serum creatinine test was "documented and reviewed" for quality-reporting purposes, and a second (added 2017, not shown as terminated) records a documented history of renal failure or a baseline creatinine threshold as a measure exclusion criterion — neither pays for performing a creatinine test. No HCPCS Level II code names potassium or creatinine as the billable service. The billable code is a CPT (HCPCS Level I) code, which this report does not reproduce.
Because the test is a clinical diagnostic laboratory test (CDLT) rather than an advanced diagnostic laboratory test — it is not single-laboratory, DNA/RNA/protein-algorithm-based, or FDA-cleared as such — its Medicare Part B payment is set under 42 CFR 414.507's general rule: "the payment rate for a CDLT furnished on or after January 1, 2018, is equal to the weighted median for the test," calculated by "arraying the distribution of all private payor rates, weighted by the volume for each payor and each laboratory," with a year-over-year reduction capped at 15 percent for 2026 through 2028 [2]. This entire structure implements "1833(h)(8) of the Act and 1834A of the Act" under 42 CFR 414.500 — an ordinary Part B diagnostic-testing budget line, not a device benefit — and separately, 42 CFR 410.32 requires that the test be "ordered by the physician who is treating the beneficiary," or it "is not reasonable and necessary" [3]. Nothing in this mechanism is specific to potassium or creatinine; it is the same machinery this repo's ctdna-mrd-assay-validation reimbursement report found governing a genomic assay, applied here to a routine chemistry analyte instead.
Three HCPCS Level II codes, all added and effective 2023-01-01 and none shown as terminated in the January 2026 file, exist specifically for home-health telecommunications: G0320 (two-way audio-video telemedicine), G0321 (audio-only telemedicine), and G0322, whose own descriptor reads "the collection of physiologic data digitally stored and/or transmitted by the patient to the home health agency (i.e., remote patient monitoring)" [1]. But the underlying regulation these codes report against is explicit that the cost is not separately reimbursed: 42 CFR 409.46(e) defines "remote patient monitoring" as "the collection of physiologic data (for example, ECG, blood pressure, glucose monitoring) digitally stored and/or transmitted by the patient or caregiver or both to the home health agency," and states "the costs of any equipment, set-up, and service related to the technology are allowable only as administrative costs" [4]. Read together, a potassium or creatinine RPM device used under a home health plan of care could be reported on the claim via G0322, but the cost of the device and the monitoring service itself would be absorbed inside the Home Health Prospective Payment System's bundled per-episode rate, not paid as a separate line — a distinct, harder budget question than the physician-office CLFS route above.
The dossier's reimbursement section (2026-08-26) named G0511 as a "remote-monitoring-adjacent" HCPCS code sourced from secondary vendor material, explicitly not independently verified. This pass verified it directly against both a Federal Register document and the master file itself. FR Doc 2024-25382 (the CY2025 Physician Fee Schedule final rule) states CMS "began to use the term general care management when we established the HCPCS code G0511 for CY 2018" [6], and separately discusses remote physiologic monitoring and remote therapeutic monitoring as their own billable category ("CTBS") distinct from Advanced Primary Care Management [6]. The master file's current record for G0511 describes only "general care management, 20 minutes or more of clinical staff time for chronic care management services or behavioral health integration services" — no monitoring language in the descriptor itself — and carries Action Code "D" ("Discontinue procedure or modifier code") with a Termination Date of 2025-12-31 [1]. G0511 is not an available billing path for any device in this domain today.
CMS's proposed RAPID coverage pathway (FR Doc 2026-16368, a notice with a comment period closing 2026-10-13, not a final rule) is limited to Class II/III FDA Breakthrough-designated devices that are "separately payable" and "not already the subject of a controlling Medicare NCD" [5]. The notice's own text addresses IVDs directly: "IVDs, including diagnostic laboratory tests, are a highly specific area of coverage policy development, and CMS has historically delegated the review of many of these products to specialized MACs. We believe that the majority of coverage determinations for IVDs which have been granted Breakthrough Device designation should continue to be determined by the MACs through existing pathways" [5]. A device that measures potassium directly is an IVD by this reasoning and would not route through RAPID even if finalized; a non-invasive screening device would not face the same exclusion. Separately, a Local Coverage Determination titled "Frequency of Laboratory Tests" (LCD 35099, administered by Novitas Solutions LLC) exists and has been the subject of at least one formal beneficiary complaint dismissed by an HHS administrative law judge for procedural defects [7]; this pass could not retrieve the LCD's own text (see below), so no specific frequency limit for electrolyte or renal-function-panel testing is reported.
[1] HCPCS Level II Alpha-Numeric Coding System file, January 2026 (codes G0511, G0322, G0321, G0320, G9147, G8774, G8775, G8776, G9722, J2540, J3480, J9292 among others) — Centers for Medicare & Medicaid Services (file dated 2026-01-12; downloaded and searched directly 2026-09-01). CMS HCPCS Level II file, coverage/action/date fields per its own record layout — https://www.cms.gov/files/zip/january-2026-alpha-numeric-hcpcs-file.zip [federal-registry] [2] 42 CFR 414.507, Payment for clinical diagnostic laboratory tests — eCFR, retrieved via this repo's regulation connector (issue 2026-08-13; accessed 2026-09-01). 42 CFR 414.507 — https://www.ecfr.gov/current/title-42/chapter-IV/subchapter-B/part-414/subpart-G/section-414.507 [federal-registry] [3] 42 CFR 414.500, Basis and scope — eCFR, retrieved via this repo's regulation connector (issue 2026-08-13; accessed 2026-09-01). 42 CFR 414.500 — https://www.ecfr.gov/current/title-42/chapter-IV/subchapter-B/part-414/subpart-G/section-414.500 [federal-registry] [4] 42 CFR 409.46, Allowable administrative costs — eCFR, retrieved via this repo's regulation connector (issue 2026-08-13; accessed 2026-09-01). 42 CFR 409.46 — https://www.ecfr.gov/current/title-42/chapter-IV/subchapter-B/part-409/subpart-C/section-409.46 [federal-registry] [5] Medicare Program; Regulatory Alignment for Predictable and Immediate Device (RAPID) Coverage Pathway — Federal Register, Centers for Medicare & Medicaid Services (published 2026-08-11; accessed 2026-09-01), confirmed live via this repo's policy connector. FR Doc 2026-16368 (91 FR 51710) — https://www.federalregister.gov/documents/2026/08/11/2026-16368/medicare-program-regulatory-alignment-for-predictable-and-immediate-device-rapid-coverage-pathway [federal-registry] [6] Medicare and Medicaid Programs; CY 2025 Payment Policies Under the Physician Fee Schedule and Other Changes to Part B Payment and Coverage Policies — Federal Register, Centers for Medicare & Medicaid Services (published 2024-12-09; accessed 2026-09-01), confirmed live via this repo's policy connector. FR Doc 2024-25382 (89 FR 97710) — https://www.federalregister.gov/documents/2024/12/09/2024-25382/medicare-and-medicaid-programs-cy-2025-payment-policies-under-the-physician-fee-schedule-and-other [federal-registry] [7] In re LCD Complaint: Frequency of Laboratory Tests, LCD ID Number 35099 — HHS Departmental Appeals Board, Administrative Law Judge decision (decided 2020; accessed 2026-09-01). LCD 35099, docket CR5772 — https://www.hhs.gov/about/agencies/dab/decisions/alj-decisions/2020/alj-cr5772/index.html [other] [8] 42 CFR 410.32, Diagnostic x-ray tests, diagnostic laboratory tests, and other diagnostic tests: Conditions — eCFR, retrieved via this repo's regulation connector (issue 2026-08-13; accessed 2026-09-01). 42 CFR 410.32 — https://www.ecfr.gov/current/title-42/chapter-IV/subchapter-B/part-410/subpart-B/section-410.32 [federal-registry] [9] 42 CFR 414.502, Definitions — eCFR, retrieved via this repo's regulation connector (issue 2026-08-13; accessed 2026-09-01). 42 CFR 414.502 — https://www.ecfr.gov/current/title-42/chapter-IV/subchapter-B/part-414/subpart-G/section-414.502 [federal-registry]
Well established: That no HCPCS Level II code prices a potassium or creatinine laboratory test rests on a direct, exhaustive text search of CMS's own master file, stated plainly because it is the primary registry itself, not a directional account of it [1]. The CDLT payment mechanism — weighted-median pricing, the 15-percent phase-in cap, the physician-ordering requirement, and the Part B budget basis — rests on four sections of federal regulation confirmed live this pass against the eCFR API [2][3][8][9]. That home-health remote patient monitoring is defined and confined to "administrative costs" rather than separate billing rests on 42 CFR 409.46 itself, read alongside the three HCPCS codes (G0320-G0322) that report the same activity [1][4]. That the RAPID pathway expects IVD coverage to continue through existing MAC processes rests on the notice's own text, independently re-verified by this pass rather than taken from this domain's dossier [5]. All of these are primary federal registry or rule text and are stated without a sourcing marker for that reason.
Thin: G0511's discontinuation and its current CCM/BHI-only descriptor rest on one government document (the master file) plus one Federal Register document that only establishes the code's 2018 origin, not its later content changes — no third source tracks the code's descriptor history year over year [single-source] [1][6]. LCD 35099's existence and administering contractor rest on one HHS adjudicative decision that dismissed the underlying complaint on procedural grounds and did not itself quote the LCD's substantive coverage criteria [single-source] [7].
Rescoped from class 3: "Will CMS finalize the RAPID pathway to cover a Breakthrough-designated device in this domain?" is not answerable — it is a prediction about a future agency decision on a notice whose comment period does not close until 2026-10-13. Its answerable twin — what the proposed notice's own eligibility text currently says about in-vitro-diagnostic devices — was researched instead and is reported above [5].
Out of scope: CPT (HCPCS Level I) descriptor text throughout, per the scope note above — no CPT code descriptor is reproduced anywhere in this report, and even the bare CPT code number for potassium or creatinine testing is not stated, consistent with this report's stricter reading of the manifest's scope note. Non-US coverage and payment policy; no connector in this repo queries one. Veterinary/animal reimbursement does not apply to this human-population domain.
Not searched vs. not found: Not retrieved — the CMS Medicare Coverage Database's own page for LCD 35099 (HTTP 403 to direct fetch), the CMS National Coverage Determinations Manual PDF (HTTP 403), a CMS Clinical Laboratory Fee Schedule fact sheet (HTTP 403), and the eCFR web interface for 409.46 (redirected to a bot-mitigation page) — this repo's regulation connector reached 409.46's text through the eCFR API rather than the blocked web UI, which is why it appears above despite the web-UI failure. Not retrieved — the FDA CLIA-waived-analyte search results page for potassium (HTTP 404 on two URL forms attempted), so no specific cleared point-of-care potassium or creatinine test system is named as CLIA-waived in this report; a WebSearch summary named several manufacturers, but a search-engine synthesis is not a source of record and is deliberately not carried here as a finding. Not searched — state Medicaid fee schedules and coverage policy for outpatient chemistry panels (two state DME/lab fee-schedule PDFs were located by search but returned unreadable compressed content on fetch, and are not cited); Medicare Advantage plan-level and commercial payer coverage bulletins specific to point-of-care potassium or creatinine testing; the CLIA certificate-of-waiver fee structure itself. Not found in the search conducted, but not independently confirmed against CMS's own NCD manual (which this pass could not retrieve) — a national NCD specifically naming electrolyte, basic-metabolic-panel, or potassium/creatinine testing; this is recorded as an unresolved gap rather than a finding, precisely because the manual itself was never read by this pass.
[inference] The pattern across §3 — a routine chemistry analyte with no dedicated HCPCS Level II code, a home-health RPM regulation that bundles the cost rather than paying it separately, and a proposed accelerated coverage pathway that expects IVDs to stay on the existing MAC track — is consistent with (but does not establish) a reimbursement landscape where a device in this domain would have to compete for margin inside an existing bundled or weighted-median rate rather than receive a new, separately payable code of its own. This sentence is the writer's own synthesis of the sourced material above, not a finding any single source states.
| Proposition | Evidence class | Resolvable identifier | Dossier section |
|---|---|---|---|
| No code in CMS's January 2026 HCPCS Level II Alpha-Numeric master file names potassium or creatinine as a billable laboratory test; all "potassium" matches are drug/IV-fluid codes and one non-covered treatment-protocol code, and all "creatinine" matches are quality-measure documentation codes | 1 registry | CMS HCPCS Level II file, January 2026 (codes G9147, G8774, G8775, G8776, G9722) | Reimbursement |
| 42 CFR 414.507 sets Medicare payment for a clinical diagnostic laboratory test at the weighted median of reported private payor rates, capped at a 15 percent year-over-year reduction for 2026 through 2028 | 1 registry | 42 CFR 414.507 | Reimbursement |
| 42 CFR 409.46(e) defines home-health remote patient monitoring and states that the costs of the equipment, set-up, and service are allowable only as administrative costs, not separately billable | 1 registry | 42 CFR 409.46 | Reimbursement |
| HCPCS code G0511 carries Action Code "D" and a Termination Date of 2025-12-31 in CMS's January 2026 master file, and its current descriptor covers only chronic care management and behavioral health integration clinical staff time, with no remote-monitoring language | 1 registry | CMS HCPCS Level II file, January 2026, code G0511 | Reimbursement |
| FR Doc 2026-16368 (the RAPID coverage pathway notice) states that CMS expects the majority of coverage determinations for Breakthrough-designated IVDs to continue to be made by Medicare Administrative Contractors through existing pathways rather than through the new pathway | 1 registry | FR Doc 2026-16368 | Reimbursement |
| HCPCS codes G0320, G0321 and G0322 — covering home-health synchronous telemedicine and remote patient monitoring data collection respectively — were added to the HCPCS Level II master file effective 2023-01-01 and are not shown as terminated as of the January 2026 file | 1 registry | CMS HCPCS Level II file, January 2026, codes G0320-G0322 | Reimbursement |