The Miniature Spectrometer on Your Wrist

Low-cost optical technology could bring laboratory-level precision to wearable devices for monitoring of blood glucose and other biomarkers

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The convolutional spectrometer uses near-infrared light to measure glucose, lactate, and alcohol through the skin without collecting blood.
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The packaged device measures approximately 4.8 × 6.2 cm, weighs 16.5 g, costs an estimated $10 in components, and processes spectra in less than 0.4 seconds.
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In approximately 6,000 spectra from 126 participant sessions, mean absolute errors were 0.36 mmol/L for glucose, 0.81 mmol/L for lactate, and 1.70 mg/dL for alcohol.
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A personalized model tracked one participant’s glucose fluctuations over several days with a mean absolute error of 0.16 mmol/L.
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Glucose prediction models did not transfer reliably between individuals, and the technology remains experimental rather than a validated alternative to laboratory testing.

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