Djassemi O; University of California San Diego,  United States.
Chang AY; McGuire WC; Mitchell E; Saha T; Fernandes T; Yang J;
Miller M; Wurster C; Morales-Fermin S; McGregor I; Castillo-Valdovinos J;
Malhotra A; Wang J
[Not strictly CPET data but could be. interesting; Dr Paul Older]

ACS Sensors. 11(2):1413-1424, 2026 Feb 27.

Continuous lactate monitoring is critical for early detection and
management of sepsis, shock, and metabolic stress, yet current serum
assays remain invasive, intermittent, and resource-intensive. We present a
clinical evaluation of a minimally invasive microneedle-based
electrochemical biosensor for real-time interstitial fluid (ISF) lactate
monitoring. The microneedle biosensor features a platinum working
electrode modified with a lactate oxidase reagent layer and a polyvinyl
chloride anti-fouling membrane for H2O2-mediated amperometry, toward
highly selective and stable ISF lactate detection. In a pilot study of
twenty-one participants across an intensive care unit, emergency
department, cardiopulmonary exercise testing, and controlled laboratory
settings, two enzyme-based microneedle sensors placed on the forearm and
thigh continuously tracked lactate for 4 h. Sensor performance
demonstrated strong agreement with blood lactate assays (r = 0.94), high
diagnostic accuracy for hyperlactatemia (>4 mmol/L; receiver operating
characteristic analysis, area under the curve = 0.95), and minimal bias
(-0.028 mmol/L) over a wide dynamic range (0.7-22.9 mmol/L) with high
selectivity against interferents. No significant ISF-blood differences (p
> 0.05) or adverse events were observed. These findings establish
microneedle biosensors as a promising platform for precision medicine,
with considerable potential to transform sepsis care, guide resuscitation,
and improve assessment of exertional dyspnea.