# US 11,076,781 B2 · Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis

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- Number: US 11,076,781 B2
- Document ID: US11076781B2
- Status: Granted
- Kind: B2
- Application number: 16/120,369
- Filed: 2018-09-03
- Published: 2019-01-17
- Granted: 2021-08-03
- Earliest claimed: 2008-05-22
- Assignees: St. Louis Medical Devices, Inc.
- Applicants: St. Louis Medical Devices, Inc.
- Inventors: Zhi Xu
- Web page: https://patentgrep.com/patent/US11076781B2

## CPC

- A61B 5/14532: {for measuring glucose, e.g. by tissue impedance measurement}
- A61B 5/1455: using optical sensors, e.g. spectral photometrical oximeters
- A61B 5/6826: {Finger}
- A61B 5/6838: {Clamps or clips}
- A61B 5/7225: {Details of analogue processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation (input circuits for detecting, measuring, or recording bioelectric or biomagnetic signals A61B5/30; specific diagnostic methods using bioelectric or biomagnetic signals A61B5/316)}
- G16Z 99/00: Subject matter not provided for in other main groups of this subclass
- A61B 2562/0238: Optical sensor arrangements for performing transmission measurements on body tissue
- A61B 2576/00: Medical imaging apparatus involving image processing or analysis (A61B1/00009, A61B6/52 and A61B8/52 take precedence)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G16Z: INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS, NOT OTHERWISE PROVIDED FOR

## Abstract

Systems and methods are disclosed for non-invasively measuring blood glucose levels in a biological sample based on spectral data. This includes utilizing at least one light source configured to strike a target area of a sample, utilizing at least one light filter positioned to receive light transmitted through the target area from the at least one light source, utilizing at least one light detector positioned to receive light from the at least one light source and filtered by the at least one light filter, and to generate an output signal, having a time dependent current, which is indicative of the power of light detected, receiving the output signal from the at least one light detector with a processor and based on the received output signal, calculating the attenuance attributable to blood in a sample with a signal-to-noise ratio of at least 20-to-1; and determining a blood glucose level.

## Claims

### Claim 1

A system for detecting glucose in a biological sample, comprising:
a processor programmed to calculate a change in a light absorption caused by blood in the biological sample and configured to receive an output photocurrent signal from at least one photocurrent signal generating light detector and calculate an attenuance attributable to blood in a sample present in the target area with a signal-to-noise ratio of at least 20-to-1 based on the received output photocurrent signal, and determine a blood glucose level associated with a sample present in the target area based on the calculated attenuance, wherein the processor is configured to calculate a peak-to-valley height of the change in light absorption due to blood in the sample in relationship to time, which is a function of a standard deviation of a logarithm of the time dependent output current divided by a proportionality constant:
Δ
⁢
⁢
A
=
σ
⁡
[
A
⁡
(
t
)
]
k
=
σ
⁡
[
log
⁢
⁢
I
D
⁡
(
t
)
]
k
,
where A(t) is the change in light absorption due to blood in the sample as a function of time, ΔA is the peak-to-valley height of A(t) plot during the time interval of one heartbeat, ID(t) is the time dependent detector current, log ID(t) is the logarithm of the time dependent detector current, k is the proportionality constant, σ[A(t)] is the standard deviation of A(t), and σ[log ID(t)] represents the standard deviation of log ID(t), wherein the processor is programmed to reduce noise without increase data acquisition time by using the σ[A(t)].

### Claim 2 (depends on 1)

The system for detecting glucose in a biological sample according to claim 1, wherein the time dependent output current is a function of a baseline current, a noise current and a time dependent cyclic current corresponding to a heartbeat.

### Claim 3 (depends on 2)

The system for detecting glucose in a biological sample according to claim 2, wherein the calculated attenuance is based at least in part on a standard deviation of a logarithm of the time dependent output current generated by the light power from a target area of the biological sample.

### Claim 4 (depends on 2)

The system for detecting glucose in a biological sample according to claim 2, wherein the calculated attenuance is based at least in part on an approximation of a standard deviation of a logarithm of the time dependent output current generated by the light power from a target area of the biological sample.

### Claim 5

A method for detecting glucose in a biological sample, comprising:
receiving an output photocurrent signal from the at least one photocurrent signal generating light detector;
programming a processor to calculate a change in a light absorption caused by blood in the biological sample based on the received output photocurrent signal;
calculating an attenuance attributable to blood in the biological sample present in the target area with a signal-to-noise ratio of at least 20-to-1;
determining a blood glucose level associated with the biological sample present in the target area based on the calculated attenuance with the processor, wherein the processor is configured to calculate a peak-to-valley height of the change in light absorption due to blood in the sample in relationship to time, which is a function of a standard deviation of a logarithm of the time dependent output current divided by a proportionality constant:
Δ
⁢
⁢
A
=
σ
⁡
[
A
⁡
(
t
)
]
k
=
σ
⁡
[
log
⁢
⁢
I
D
⁡
(
t
)
]
k
,
where A(t) is the change in light absorption due to blood in the sample as a function of time, ΔA is the peak-to-valley height of A(t) plot during the time interval of one heartbeat, ID(t) is the time dependent detector current, log ID(t) is the logarithm of the time dependent detector current, k is the proportionality constant, σ[A(t)] is the standard deviation of A(t), and σ[log ID(t)] represents the standard deviation of log ID(t); and
programming the processor to reduce noise without increase data acquisition time by using the σ[A(t)].

### Claim 6 (depends on 5)

The method for detecting glucose in a biological sample according to claim 5, wherein the step of calculating the attenuance attributable to blood in a sample present in the target area is based at least in part on a standard deviation of a logarithm of the time dependent output current.

### Claim 7 (depends on 1)

The system for detecting glucose in a biological sample according to claim 1 further comprising at least one light source configured to generate one or more light beams and to strike a target area of a biological sample.

### Claim 8 (depends on 1)

The system for detecting glucose in a biological sample according to claim 1 further comprising at least one light filter positioned to receive light transmitted through a target area of the sample from at least one light source.

### Claim 9 (depends on 1)

The system for detecting glucose in a biological sample according to claim 1 further comprising at least one photocurrent signal generating light detector positioned to receive light from a at least one light source and filtered by at least one light filter, and to generate an output photocurrent signal, having a time dependent output current, which is indicative of the power of light detected.

### Claim 10 (depends on 5)

The method for detecting glucose in a biological sample according to claim 5, comprising utilizing at least one light source configured to generate one or more light beams and to strike a target area of a biological sample.

### Claim 11 (depends on 5)

The method for detecting glucose in a biological sample according to claim 5, comprising utilizing at least one light filter positioned to receive light transmitted through the target area of the sample from the at least one light source.

### Claim 12 (depends on 5)

The method for detecting glucose in a biological sample according to claim 5, comprising utilizing at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and filtered by the at least one light filter, and to generate an output photocurrent signal, having a time dependent output current, which is indicative of the power of light detected.