01 / DISPOSABLE
Skin-contact K+ cartridge
K1/K2/K3 valinomycin ion-selective electrodes, an ionophore-free blank for drift control, dual Ag/AgCl references, hydrogel wet island, and a guard ring for contact diagnostics.
Wearable continuous potassium monitoring
Disposable
K1/K2/K3
Reusable reader
2x RE
Output rule
Fail closed
A wearable continuous potassium monitor for high-risk cardiac, renal, and post-acute populations.
Triplicate K+ ion-selective electrodes, dual Ag/AgCl references, and a fail-closed reader. The underlying electrochemistry is measurable today; the deliverable is a validated trend monitor that triggers earlier confirmatory blood testing in patients where intermittent laboratory monitoring has documented gaps.
Research stage
Pre-validation
Not a medical device
Product architecture
Three components, one analyte, one output rule.
Wearable CKM is a single-analyte device by design: redundant K+ chemistry, calibrated electronics, and a fail-closed output rule that suppresses results outside defined confidence bounds.
02 / REUSABLE
Guarded reader module
Femtoamp-input buffer, 24-bit ADC, optional impedance AFE for hydration check, temperature, BLE radio, wearable PMIC, and sealed pogo interface to the cartridge pads.
03 / OUTPUT
Fail-closed by design
The monitor reports a potassium trend only when slope, drift, reference stability, triplicate agreement, contact, and calibration age all pass defined thresholds. Otherwise output is suppressed and a confirmatory blood test is indicated.
Hardware viewer
Interactive layer-by-layer device model.
Skin interface, hydrogel, microneedle access, K+ membranes, dual references, guard ring, contact pads, and the reader analog island.
Current care gap
The critical window is managed with intermittent potassium checks.
The highest-yield first application is post-discharge HFrEF patients on potassium-altering therapy: a narrow medication-safety and arrhythmia-risk workflow during the 30- to 90-day vulnerable phase after heart-failure hospitalization.
~30%Heart-failure patients readmitted within 3 months after discharge in vulnerable-phase literature.
~10%Mortality can approach 10% during the same vulnerable period.
46.5%No serum potassium test within 7 days after MRA initiation among eligible HFrEF patients in a multicenter cohort.
13.6%No serum potassium test within 30 days after MRA initiation among patients not hospitalized, dead, or disenrolled.
Current workflowDischarge potassium is checked, medications are adjusted, the patient goes home, then potassium and creatinine are rechecked on a schedule that depends on follow-up availability, patient adherence, transportation, and lab ordering.
Known gapGuidelines call for close potassium and renal-function monitoring after MRA initiation and during medication changes, but real-world follow-through is incomplete. A patient can drift for days before the next lab.
What RPM missesRemote HF programs commonly track weight, symptoms, blood pressure, heart rate, and sometimes device data. These can detect congestion but do not directly measure the electrolyte variable that determines arrhythmia risk and medication safety.
Precise interventionCKM-HF is a 30-day post-discharge electrolyte telemetry service: baseline lab at discharge, one 7-day cartridge at a time, trend dashboard, and escalation only when the K+ trend crosses a predefined confirmation threshold.
Clinical actionAlert does not dose potassium. It triggers a potassium/creatinine/magnesium check, medication review, and clinician-directed adjustment of diuretic, supplement, MRA, RAASi, or binder strategy.
Beachhead product
CKM-HF 30: reader, four 7-day cartridges, patient onboarding, clinician dashboard, and escalation protocol for post-discharge HFrEF patients on loop diuretics, thiazide add-ons, MRA/RAASi titration, CKD, diabetes, ischemic cardiomyopathy, prior arrhythmia, or ICD history.
Confirmation thresholds
Trigger confirmatory blood testing when trend estimates approach the cardiac safety floor: projected K+ below 4.0 mmol/L, fall of at least 0.5 mmol/L from baseline, rapid directional decline, or low-confidence sensor state during high-risk medication changes.
Demand solved
Clinicians already need potassium data to safely titrate diuretics, MRA, RAASi, supplements, and binders. Wearable CKM changes the timing: from scheduled or symptom-driven labs to data-triggered confirmation during the highest-risk window.
Analytical performance
Directional accuracy is the realistic target. The underlying physics supports it.
Wearable CKM is not designed to replace a single-point blood draw for diagnosis. It is designed to detect directional potassium movement reliably enough to trigger a confirmatory blood test earlier than current intermittent care permits.
61.5 mVTheoretical Nernst slope per decade of K+ activity at body temperature for a monovalent ion.
3.6 mVVoltage difference between 4.0 and 3.5 mmol/L K+, the standard hypokalemia threshold.
7.7 mVVoltage difference between 4.0 and 3.0 mmol/L K+, associated with substantial arrhythmia risk in cardiac patients.
±0.3 mmol/LCLIA potassium acceptance limit (≈±2 mV near 4 mmol/L). Reference benchmark for analytical performance.
Reference standardHospital point-of-care analyzers (iSTAT family) report potassium CV <2% with clinically acceptable agreement to central laboratory measurement. Wearable CKM is paired against this reference.
Published microneedle K+ performanceMicroneedle K+ patches in literature demonstrate Nernstian slopes of 55-58 mV/decade, drift of approximately 0.35 mV/h, and 24 h cytotoxicity-safe wear. A calibration-free design (r-WEAR) reported 0.12 mV/h drift over 12 h and 4-day on-body operation without recalibration.
Wearable CKM performance targetsTrend bias ±0.3-0.5 mmol/L vs. paired laboratory potassium over 24-hour windows; direction accuracy ≥95% for moves ≥0.5 mmol/L; time-to-flag measured in minutes versus hours for outpatient laboratory turnaround.
LimitationThe device is not intended for standalone absolute potassium measurement. Clinical value derives from the trend between confirmation labs, not from replacing them.
Clinical applications
Six scenarios where earlier potassium signal would change the next clinical decision.
Each scenario reflects a documented gap in intermittent laboratory testing, an established arrhythmia or mortality pathway in published evidence, and a clinical action that a trend alert would advance in time.
Post-discharge heart failure on diuretics
Patients on furosemide ± thiazide may drift below 4.0 mmol/L between scheduled clinic visits. Arrhythmia and 30-day readmission risk increase steeply below 3.5 mmol/L. A trend alert prompts a confirmatory lab before clinical decompensation.
JACC reviewAcute myocardial infarction, days 1-3
STEMI cohort (n=8,624) demonstrated an adjusted odds ratio of 1.90 for ventricular fibrillation prior to primary PCI in hypokalemic patients. Diuretic-induced K+ decline superimposed on ischemic myocardium is an established reentrant arrhythmia substrate; an in-bed trend alert reduces time to bedside POC potassium measurement and correction.
JAHA cohortDKA recovery on insulin infusion
Insulin shifts K+ intracellularly. Serum potassium can fall in excess of 1 mmol/L within the first 6-12 hours of treatment, and standard q2-4 h sampling can miss the trough. Continuous trend output detects the descent between scheduled draws.
MRA and RAASi initiation
Initiation of spironolactone, eplerenone, and ACEi/ARB therapy in HFrEF requires K+ assessment at week 1 and weeks 2-4. Published data document poor real-world adherence to this schedule. A trend monitor closes the between-lab interval.
JAMA: MRA monitoringICU refeeding and volume shifts
A 506-patient ICU study (12,099 measurements) reported an odds ratio of 5.4 for 28-day mortality in the highest quartile of potassium variability. A computerized continuous protocol reduced hypokalemia incidence from 2.4% to 1.7% and hyperkalemia from 7.4% to 4.8%. Wearable CKM implements equivalent surveillance with a sensor in place of manual sampling.
PLOS ICU ICU protocolICD recipients with declining potassium
Long-QT and structurally vulnerable myocardium tolerate hypokalemia poorly. A trend alert at “below 4.0 mmol/L and declining” in an outpatient ICD recipient establishes a window for potassium replacement before appropriate or inappropriate device therapy is delivered.
Target patient populations
Where a validated Wearable CKM provides the highest clinical value.
HFHeart-failure patients on loop or thiazide diuretics, particularly during MRA or RAASi titration.
CAD/MICoronary disease and post-MI patients with vulnerable myocardium.
EPLong-QT, ICD, and recurrent-arrhythmia patients.
HTNHypertension on potassium-wasting diuretics.
GIVomiting, diarrhea, laxative use, bowel preparation.
Sport/heatEndurance athletes and heat-exposed workers with substantial sweat loss.
ICU/Post-opCritical care patients with rapid fluid, insulin, refeeding, or renal shifts.
Renal/AdrenalKidney, adrenal, and tubular disorders associated with potassium wasting.
EndocrineInsulin users, DKA recovery, and patients with substantial glucose-insulin shifts.
NutritionHypomagnesemia, alcohol use disorder, malnutrition, refeeding risk.
PolypharmacyPatients on medications affecting potassium balance or QT interval.
PrincipleGreater cardiac fragility or faster potassium shifts warrant more conservative confirmation rules.
Hospital variant
Same chemistry, different physical constraints, higher analytical headroom.
The wearable form factor is bounded by microneedle access, battery, and multi-day skin tolerance. A bedside variant operates without those constraints and is positioned as a continuous-trend complement to existing point-of-care analyzers.
Form factorTethered cartridge in a bedside cradle with larger reference reservoirs, extended fluid path, and on-demand 1-point recalibration. Single-use cartridge replaced per patient or per shift.
Sample sourceEither dermal ISF via a microneedle pod for ambulatory step-down, or a small drawn sample from existing arterial or venous lines. Removes wear-time and battery constraints.
Analytical headroomMatched references, thermostatted membranes, periodic blank measurement, and bedside-driven recalibration support tighter drift control. Targeted performance approaches iSTAT-class CV <2% on trend.
Use casesICU titration of insulin and diuretics; post-cardiac-surgery step-down; DKA recovery; refeeding protocols; MRA and RAASi initiation; transplant induction; dialysis transition.
Workflow positioningPoint-of-care analyzers measure single time points. The hospital variant provides continuous trend data between samples, replicating computerized continuous-protocol benefit with sensor-based surveillance.
Mortality model
The evidence supports a mortality-risk pool, not a claimed lives-saved number.
The first target population sits inside a large, high-mortality post-discharge window where potassium instability is mechanistically and clinically relevant. Specific lives-saved figures require the paired monitoring and outcome data the validation program is designed to produce.
~1.09M / yrEstimated annual U.S. heart-failure hospitalizations in a national cardiovascular hospitalization cost analysis.
up to ~10%Mortality can approach 10% during the 3-month vulnerable phase after acute HF discharge.
~109k / yrApproximate broad vulnerable-phase mortality pool if 1.09M discharges are multiplied by 10% risk.
unknownFraction directly preventable by potassium trend monitoring; this is the outcome study Wearable CKM must earn.
What the number means~109,000 is not a Wearable CKM lives-saved claim. It is an upper-bound estimate of deaths occurring in the broad post-discharge HF vulnerable phase, before restricting to HFrEF, diuretics, MRA/RAASi titration, CKD, diabetes, ischemic disease, arrhythmia, or ICD history.
Why potassium belongs in the modelHF literature reports risk rising below about 4.0 mmol/L and steeply below 3.5 mmol/L; hypokalemia is a recognized trigger for ventricular arrhythmia and sudden cardiac death, especially in structurally vulnerable hearts.
Why monitoring is the interventionAfter MRA initiation in HFrEF, 46.5% of eligible patients had no serum potassium measurement within 7 days and 13.6% remained untested at 30 days. Wearable CKM addresses a known monitoring failure, not an unknown clinical workflow.
Conservative hypothesisFor every 100,000 high-risk post-discharge HF patients monitored, if 10-20% of expected deaths are materially electrolyte/medication-linked and CKM-enabled earlier confirmation prevents 5-10% of those, the modeled opportunity is roughly 50-200 potentially avoidable deaths. This is a hypothesis to validate, not a clinical claim.
Study endpointThe validation program should measure time-to-confirmatory potassium test, time below 4.0 mmol/L, urgent hypo/hyperkalemia detections, medication changes prompted by CKM, ED visits, HF readmissions, ICD therapies, and all-cause mortality.
Unit economics
Cartridge wear targets one week, not one day.
Daily replacement is unnecessary at the design level. Published microneedle glucose patches operate continuously for 14 days, and calibration-free K+ ISE designs have demonstrated 4 days on-body without recalibration. Wearable CKM targets 7-day cartridges with site rotation, consistent with established CGM use patterns.
Disposable cartridge (prototype BOM)
Medical adhesive, liner, release layers$0.20-$0.80
Hydrogel wet island$0.20-$1.50
Microneedle access array$2-$12
Polyimide flex, ENIG pads, carrier$1.50-$6
K+ membranes, references, blank, QC$0.50-$3
Sterile pouch, assembly, calibration, yield loss$1-$8
Subtotal per cartridge$5-$31
Target wear per cartridge7-14 days
Reusable reader (one-time)
Custom PCB / rigid-flex assembly$3-$15
Electrometer, ADC, mux, temp, PMIC, BLE$12-$35
Battery, contacts, gasket, shell, seal$6-$27
Firmware load, calibration, factory test$5-$25
Subtotal per reader$26-$102
Mature COGS targetpost-validation
Bench validation equipmentcapital, not per unit
Investment thesis
A single avoided heart-failure hospitalization offsets multiple patient-years of monitoring.
~4 / monthCartridges per patient at 7-day target wear, with site rotation modeled on established CGM use.
$46-$226First-month per-patient cost (reader plus four cartridges) at prototype BOM ranges.
$20-$124Subsequent monthly per-patient cost (four cartridges only).
$18,000Mean U.S. heart-failure hospitalization cost (Circulation: CQO, NIS 2012-2018).
AnnualizedApproximately $240-$1,488 in cartridges per patient-year plus a one-time reader. A single avoided HF hospitalization offsets 12-75 patient-years of monitoring at prototype cost.
Initial marketHeart-failure programs, post-MI follow-up clinics, device clinics, dialysis units, and value-based payers exposed to readmission and arrhythmia hospitalization risk.
Beachhead segmentCKM-HF 30: HFrEF patients on potassium-altering therapy during the first 30 days after discharge, expanding to 90 days for persistent medication titration or recurrent instability.
Hospital armHospital variant priced as a per-shift consumable, paired with point-of-care analyzers for confirmation. Reduces a portion of routine q2-4 h venipunctures during high-risk windows (ICU, DKA, post-op, MRA initiation).
Use of capitalBench characterization (slope, drift, interference); sterile cartridge fabrication; 7- to 14-day wear validation; paired-comparator studies against laboratory potassium; preparation of the evidence package required for the next financing round and regulatory engagement.
Validation path
Four phases between prototype and a clinically defensible product.
Each phase produces evidence that retires a specific technical or clinical risk. No phase is bypassed to advance the product narrative.
P0
Bench sensor characterization
K+ ISE slope, linear range, temperature response, Na+/NH4+/pH interference, and performance in artificial interstitial fluid prior to any wear.
P1
Redundancy and reference stability
K1/K2/K3 agreement, blank-control stability, dual Ag/AgCl reference drift, hydration and contact diagnostics, and post-run calibration verification.
P2
Wearable build and characterization
Sterile disposable cartridge and reusable reader assembled and characterized after bench drift, interference, sealing, and wet-interface results meet defined thresholds.
P3
Paired-comparator study
Investigator-led prototype testing and small-cohort evaluations comparing Wearable CKM trend output to laboratory serum, plasma, or blood-gas potassium under a defined protocol.
Disclosures
Claims are bounded by present evidence.
Laboratory potassium remains the reference standard. Every statement on this page reflects what the current prototype can defend with available data.
Does not claim
Serum replacement, hypokalemia or hyperkalemia diagnosis, medication dosing guidance, cardiac arrest prevention, validated home self-testing, or finished medical-device status.
Does claim
A potassium-specific monitor architecture with measurable underlying physics, a defined analytical performance target, redundant chemistry, fail-closed output rules, and a fundable validation path for high-risk patient populations.