Masimo’s approach to noninvasive blood glucose monitoring and its fight with Apple

Masimo, Irvine, CA-based global medical technology company, is also in the race to solve the puzzle of non-invasive blood glucose monitoring.

Interestingly, the company had filed several patent lawsuits against Apple in a series of court proceedings in 2020.

These can be found in “Sep. 8, 2020, Apple’s Preliminary Invalidity Contentions, and including Exhibits A-G, Masimo Corporation, and Cercacor Laboratories, Inc. v. Apple Inc., Case No. 8:20-cv-00048, 3960 pages.” 

There were largely seven different patents subject to Inter Partes review between Apple and Masimo starting during the middle of 2020. The complaints around these were patent infringement, trade secret misappropriation, ownership of patents, and demand for Jury trial.

The lawsuit had also claimed that Apple got secret information under the guise of a working relationship and then hired away key employees like Mike O’Reilly who became VP of Apple’s health technology. 

In September, the company filed suit again, accusing Apple of delaying legal battle to sell more Apple Watches. Apple vs Masimo inter-pares patent review

We wanted to take a closer look at some of the latest Masimo patents that reference the inter-partes review to understand how Masimo / Apple could be approaching the challenge around non-invasive blood glucose monitoring.

Masimo’s latest filing to be approved was patent 10,945,648. This was filed by the company on Sept’2020 and approved this week on March 16, 2021.

Masimo blood glucose monitoring device

As opposed to a smartwatch or a fitness band, the company’s technology is more along the lines of a handheld device that will help measure a person’s blood glucose level without the need for a finger prick.

Masimo is not new to the world of home-based health care. The company already has a few products in the market that includes a pulse oximeter, a sleep monitoring wearable, and a digital thermometer.

Some of the latest company’s patents provide a glimpse of the company’s thinking on approaching noninvasive blood glucose monitoring.

Multi-stream infrared spectroscopy for analyte (glucose) detection

The central thinking around Masimo’s research, according to this patent, is that blood analytes can be measures noninvasively based on multi-stream infrared and near-infrared spectroscopy.

Devices capable of spectroscopic analysis generally include a light source(s) transmitting optical radiation into or reflecting off a measurement site, such as body tissue carrying pulsing blood. 

After attenuation by tissue and fluids of the measurement site, a photodetection device(s) detects the attenuated light and outputs a detector signal(s) responsive to the detected attenuated light.

 A signal processing device(s) process the detector(s) signal(s) and outputs a measurement indicative of a blood constituent of interest, such as glucose, oxygen, methemoglobin, total hemoglobin, other physiological parameters, or other data or combinations of data useful in determining a state or trend of wellness of a patient. 

The Masimo handheld blood glucose monitor has an attachment that houses LEDs and super-luminescent LEDs.

These LEDs are designed to emit light with about 1610 nm, about 1640 nm, and about 1665 nm. The key is to have LEDs that can emit at wavelengths between 1600nm and 1700nm for successful measurement of blood analytes.

The Masimo form factor for non-invasive detection of blood glucose

Masimo finger based glucose monitoring
LED-based spectroscopy for noninvasive blood glucose detection

These light sources and sensors are adapted to position a finger proximate to the light source and light detector.

In this case, it is like a clothespin-shaped housing that includes a contoured bed conforming to the shape of a finger housing several photodetectors to aid in the measurement of blood glucose and other analytes.

Beyond measuring blood glucose levels, the device can also help with measuring other blood constituent or analyte, such as oxygen, carbon monoxide, methemoglobin, total hemoglobin, glucose, proteins, glucose, lipids, a percentage thereof (e.g., saturation) or for measuring many other physiologically relevant patient characteristics.  

The emitter located in the housing may be operated to allow for the measurement of an analyte like glucose. In embodiments, the emitter may comprise a plurality of LEDs that emit a sequence of optical radiation pulses across a spectrum of wavelengths. 

Also, to achieve the desired SNR for detecting analytes like glucose, the emitter may be driven using a low power progression to higher power. The emitter may also have its duty cycle modified to achieve the desired SNR. 

Apple continues its research on spectroscopy and related offerings

On Apple’s side of the fence, their research and patent filing around blood glucose monitoring continues.Comparing 2020 Apple Watch models

A prominent patent, “Terahertz Spectroscopy and Imaging in Dynamic Environments with Performance Enhancements Using Ambient Sensors,” was approved in February 2021, which showed the company’s thinking around using THz spectroscopy to detect analytes.

Apple Health Coaching
Apple health coaching patent for glucose monitoring

Other Apple work in the area focuses on how the company can design services around blood glucose monitoring. ( Potentially a Health+ subscription service on the way!)Apple medical device roles

The company has also been in hiring mode for several positions that deal with medical device regulation and operations.

When it comes to mobile health tech opportunities, it’s just not Apple looking into this massive opportunity. 

What about Google and wearOS?

Google has been busy researching and developing a series of features that users can use on their Pixel phones. Recently the company announced that users would track their heart rate and respiratory rate using the cameras on their Android phones.

The recently announced Google Nest Hub can apply convolutional neural networks to monitor sleep states and more.Sleep tracking on Google Nest Hub

When it comes to blood glucose level monitoring via a non-invasive method using mobile or smartwatch, Google has been exploring several paths.

The one that stood out for us was the use of “Fourier-transform Infrared Spectroscopy using a mobile device.” (Patent # 0200390372, filed on March 2019).

Unlike Apple’s patent, Google is pretty straightforward when it comes to declaring the purpose of this infrared spectroscopy.

According to their patent,  some of the most useful and important information about a person’s health and fitness is determined from solutes’ measurements in the person’s blood, such as blood glucose, total hemoglobin, lactate, or blood-alcohol.

Blood-glucose level measurements are used to determine the frequency and dosage of insulin for people with diabetes.

Similarly, total hemoglobin levels can be used to diagnose and monitor anemia.

In addition to disease monitoring and health indications, blood-solute measurements can be used for fitness training and to encourage responsible behavior.

For example, a measurement of lactate levels can help an athlete train to improve endurance, and measurement of blood-alcohol concentration can be used to determine whether a person should drive.

Their research document describes techniques and devices for Fourier-transform infrared (FT-IR) spectroscopy using a mobile device and, more specifically, a smartwatch.

Google wearOS Spectroscopy for noninvasive blood glucose monitoring

“The mobile devices include a light source that emits light toward an interferometer that uses mirrors to separate and recombine the light. The interferometer directs the recombined light toward a subject, particularly a living being, such as a person.

Based on the data from the photodetector, an interferogram is generated. Applying a mathematical technique such as a Fourier transform to the interferogram, a spectrum data set of the recombined light can be generated. Based on the spectrum data set, a concentration of solutes in the person’s blood can be calculated.”

Apple vs. Masimo, the road ahead for non-invasive blood glucose monitoring

This case continues as of this writing. The case is currently expected to hear the first arguments in April 2021.

Masimo is not the only company that has issues with Apple’s talent poaching type issues. Valencell, a North Carolina-based company, also had its patent issues with Apple.

Valencell makes cuffless blood pressure monitoring for wearables and is working on spectrometry-based glucose monitoring capabilities as well. In 2016, the company had sued Apple, alleging that Apple initially sought to partner with Valencell and then used its technology without licensing it. 

Either way, it is becoming evident that we are on the cusps of getting new devices based on infrared-spectroscopy to detect blood glucose in a non-invasive manner. 

Quantum Operation Inc., a Tokyo-based healthcare IoT startup, presented their noninvasive glucose monitor prototype at CES 2021, capable of measuring blood glucose in a continuous mode. 

The company’s patented spectrum sensing technology enables the monitoring sensor to accurately measure glucose in a person’s bloodstream through the skin while being worn around their wrist.

Either way, these novel products will need to go through FDA clearance and other regulatory approvals before they can be made available. 

Noninvasive blood glucose monitoring eliminates the need and pain of daily needle uses for diabetic patients.

CDC estimates 34.2 million Americans have diabetes and 88 million have prediabetes. Hence, this technology, whether as a standalone device or in the form of a smartwatch/fitness tracker, will definitely be a huge deal.

Previous articleGoogle Assistant Not Working on Fitbit Versa 3 or Sense? Let’s fix it
Next articleFitbit Ace 3 VS Garmin vivofit jr. 3: what’s the best activity tracker for your kids?
Sudz Niel Kar
I am a technologist with years of experience with Apple and wearOS products, have a BS in Computer Science and an MBA specializing in emerging tech, and owned the popular site AppleToolBox. In my day job, I advise Fortune 500 companies with their digital transformation strategies and also consult with numerous digital health startups in an advisory capacity. I'm VERY interested in exploring the digital health and fitness-tech evolution and keeping a close eye on patents, FDA approvals, strategic partnerships, and developments happening in the wearables and digital health sector. When I'm not writing or presenting, I run with my Apple Watch Ultra or Samsung Galaxy Watch and closely monitor my HRV and other recovery metrics.


  1. CGMs today only claim “accuracy” +/- 20%- the statistical average across tier range. Their makers describe them as insufficient for making insulin dose adjustments when the user doesn’t “feel” they are accurate.

    That’s a lot to expect from diabetics who can’t “feel” when their blood sugar is elevated or can’t “feel” they are low until they are low.

    When do they feel the CGM isn’t right?

    When one alarms that they are dangerously low but they feel fine, stops working, won’t pair, reports levels that are improbable.


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.