PaperarXiv:2609.30122
Melanin- and linewidth-corrected pulse-oximetry
arXiv preprint (eess / biomedical optics)
Open code
TL;DR
Fits three SpO2 calibration forms (empirical linear; mBLL-derived with offset; melanin- and linewidth-aware mBLL) on the public OpenOximetry cohort — 98 patients with paired ABG SaO2, recoverable RoR from raw red/IR PPG, and melanin volume fraction M from reflectance. Overall accuracy is nearly identical (~2.42% Arms), but residual dependence on M falls from about +2.8 → +1.2 → +0.1 pp SaO2 per unit melanin fraction across the three cases (direction consistent with spectral-coloring theory; slopes not statistically resolved at n=98; authors estimate ~10× cohort needed). Melanin-aware case needs a per-patient skin-tone measurement and assumed LED FWHM.
- Form factor: finger
Abstract
Current pulse oximeters tend to overestimate arterial saturation in darkly pigmented patients, increasing occult hypoxemia rates. One proposed mechanism is spectral coloring: melanin contributes to reshaping the detected spectrum of a broad-linewidth source, making the wavelength-dependent parameters behind calibration skin-tone-dependent. Diffuse optics theory allows for a melanin- and linewidth-corrected calibration equation, which to our knowledge has never been tested in vivo. In this work, we fit the empirical linear equation, the diffuse optics theoretical equation, and its corrected form to the public OpenOximetry Repository—considering 98 patients with paired arterial blood-draws, raw photoplethysmograms, and skin reflectance spectra. Accuracy is practically indistinguishable between the three approaches, yet the saturation error's dependence on melanin falls from +2.8 to +1.2 to +0.1 percentage points per unit melanin volume fraction—consistent with the spectral-coloring theory. None of these dependencies on melanin are statistically resolved here—a cohort roughly ten times larger is needed—so the correction is backed by theory and its expected direction. All three calibration approaches carry two degrees of freedom: the theoretical equation drops into existing calibration procedures, and its melanin-aware form needs a per-patient skin-tone measurement. This work demonstrates how the theoretical pulse oximetry model can be applied in calibration.
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Tasks & signals
Tasks
Signals
Keywords
How it works
- Wavelengths
- red, IR
Cite this paper
APA
Blaney, G., Frias, J., Durbha, R., Fantini, S., & Koomson, V. (2026). Melanin- and linewidth-corrected pulse-oximetry. arXiv preprint. https://doi.org/10.48550/arXiv.2609.30122
BibTeX
@misc{blaney2026melanin,
title = {{Melanin- and linewidth-corrected pulse-oximetry}},
author = {Blaney, Giles and Frias, Jodee and Durbha, Ravi and Fantini, Sergio and Koomson, Valencia},
year = {2026},
howpublished = {arXiv preprint},
doi = {10.48550/arXiv.2609.30122},
eprint = {2609.30122},
archivePrefix = {arXiv}
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