The Spectros T-Stat™ 303 Microvascular The Tissue Oximeter is intended for use as an adjunct monitor of the localized hemoglobin oxygen saturation of blood in the microvascular tissue spaces (StO2%) in infants, children, or adults at risk for reduced-flow and no-flow ischemic states.

The prospective clinical value of measurements made with the T-Stat™ Oximeter has not been demonstrated in disease states. The T-Stat™ Oximeter should not be used as the sole basis for diagnosis or therapy.

Device Description

The Spectros T-Stat™ 303 Tissue Oximeter is a broadband, multiwavelength, Visible Light Spectroscopy (VLS) monitoring system for measuring the saturation of hemoglobin with oxygen in the microvascular tissue spaces (StQ2%).

The complete system consists of a disposable sensor probe connected to a software-driven electronic monitor. Data collection, analysis, and display functions are provided by the monitor. Illumination of the tissue is provided by a visible light source in the sensor probe placed near, on, or into the target tissue to be studied. Reflected light is captured and returned to the monitor via a detachable connection at the monitor end of the patient probe. StO2% is estimated using differential optical diffuse reflectance spectroscopy and fitting for background scattering over a range of reflected visible wavelengths.

AI/ML Overview

The Spectros T-Stat™ 303 Microvascular Tissue Oximeter's acceptance criteria are not explicitly stated in the provided text as numerical thresholds for performance metrics. Instead, the document describes the device's performance in comparison to predicate devices and previously published studies to establish substantial equivalence.

Here's an analysis of the provided information, structured around your request:

1. Table of Acceptance Criteria and Reported Device Performance

As specific acceptance criteria (e.g., "accuracy must be > 90%") are not detailed, this table will reflect the comparative performance statements provided in the submission.

Performance Aspect	Acceptance Criteria (Implied)	Reported Device Performance
Hemoglobin Spectra & Desaturation Binding Curves	Accurate measurement	Accurately measured in peer-reviewed in vitro studies.
Bias against NIRS Predicates (StO2%)	Unbiased	-1% ± 5% (p=N.S.) when compared to NIRS predicates.
Range of Normal (StO2%)	Tighter range than NIRS predicates	62-75% for VLS vs. 48-88% for NIRS (p<0.001).
Sensitivity to Reduced-flow & No-flow Ischemic States	Demonstrated sensitivity	Demonstrated sensitivity in peer-reviewed animal and human studies (p<0.001).

2. Sample Size Used for the Test Set and Data Provenance

The document does not explicitly state the sample sizes for human or animal studies that generated the performance data.

Test Set Sample Size: Not explicitly stated. The document refers to "peer-reviewed animal and human studies."
Data Provenance: The studies are described as "peer-reviewed animal and human studies." No specific country of origin is mentioned. The studies appear to be prospective, as the device is being tested for its functional performance.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

This information is not provided in the document. The studies are referred to as "peer-reviewed," which implies scientific scrutiny, but details on ground truth establishment are absent.

4. Adjudication Method for the Test Set

The adjudication method is not described in the provided text.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

An MRMC study was not conducted as described. The focus is on the device's standalone performance and its comparison to other measurement methods (NIRS, pulse oximetry) and general "predicate devices," rather than on how human readers improve with AI assistance.

6. Standalone (Algorithm Only) Performance

Yes, standalone performance was done. The document focuses exclusively on the performance of the T-Stat™ device (alcohol only) in making measurements.

"T-Stat™ accurately measured hemoglobin spectra and desaturation binding curves in peer-reviewed in vitro studies."
"T-Stat™ StO2% determined using VLS was unbiased in comparison to StO2% determined using NIRS predicates..."
"T-Stat™ VLS tissue oximetry was demonstrated sensitive to reduced-flow and no-flow ischemic states..."

These statements describe the direct output and accuracy of the device's measurements.

7. Type of Ground Truth Used

The type of ground truth appears to be based on:

Comparison to established methods/predicates: For StO2% bias, it was compared to "StO2% determined using NIRS predicates."
Physiological gold standards: For sensitivity to ischemic states, it was
demonstrated against "reduced-flow and no-flow ischemic states," which represent clear physiological conditions. For in vitro studies, it measured "hemoglobin spectra and desaturation binding curves," presumably against known chemical or spectroscopic standards.

8. Sample Size for the Training Set

The document does not provide information on a training set. The descriptions relate to evaluation studies rather than the development of a machine learning model with distinct training and test sets.

9. How the Ground Truth for the Training Set Was Established

As no training set is described, this information is not applicable.

Summary

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Spectros Corporation

NOV - 5 2004 4370 Alpine Road #108, Portola Valley CA 94028-7927 Phone 650.851.4040 Fax 650.851.4099

David A. Benaron, M.D. e-mail: dbenaron@spectros.com

Section 40 - 510(k) Summary

[This section supersedes and replaces Section 29 of the Application]

I. Applicant Information

A. Date of Summary:	October 28, 2004
B. Manufacturer	Spectros Corporation4370 Alpine Road, Suite 108Portola Valley CA 94028
C. Official Contact:	David A. Benaron, MDCEO and PresidentSpectros CorporationSuite 1084370 Alpine RoadPortola Valley CA 94028
D. Contact Info:	Phone: (650) 851-4040Fax: (650) 851-4099E-mail: dbenaron@spectros.com

II. Device Information

A. Proprietary Name: T-Stat™ 303 Microvascular Tissue Oximeter B. Common Name: Tissue Oximeter C. Classification Name: Oximeter, Tissue (870.2700) D. Product Code: MUD E. Regulatory Class: Class II F. Panel: Cardiovascular

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III. Predicate Devices

The following devices are cited as predicates:

Exhibit 40-1 Predicate Tissue Oximeter Devices Summaries

#	Predicate Feature	Manufacturer	Device	K-Number
1.	Tissue Oximeter	Hutchinson	InSpectra 325	K023938
2.	Tissue Oximeter	Somanetics	Invos 5100	K001842
3.	Relative Hemoglobin	Nellcor	N-395	K991823
4.	Site-Specific: Oral	Olympus	XENF-DP	K011869
5.	Site-Specific: Colon	Olympus	LF-DP	K002231
6.	Site-Specific: Endo	Olympus	Thoracoscope /Laparoscope	K915857

IV. General Description

V. Indications

The Spectros T-Stat™ 303 Microvascular Tissue Oximeter is intended for use as an adjunct monitor of the localized hemoglobin oxygen saturation of blood in the microvascular tissue spaces (StO2%) in infants, children, or adults at risk for reduced-flow and no-flow ischemic states.

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KO40684

6.315

VI. In Vitro and In Vivo Test Data

In studies of T-StatTM:

T-Stat™ accurately measured hemoglobin spectra and desaturation binding curves in peer-reviewed in vitro studies.
T-Stat™ StO2% determined using VLS was unbiased in comparison to StO2% determined using NIRS predicates (StO2% Bias = - 1% ± 5%, p=N.S.), but VLS demonstrated significantly tighter ranges of normal in peer-reviewed animal and human studies (VLS normal range 62-75% vs. NIRS reported at 48-88%, p<0.001).
T-Stat™ VLS tissue oximetry was demonstrated sensitive to reduced-flow and no-flow ischemic states in peer-reviewed animal and human studies (p<0.001).
T-Stat™ VLS tissue oximetry provides readings in low and no flow -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------ischemic states in human clinical studies.

VI. Comparison to Predicate Devices

A. Similarities

Both T-Stat™ and the predicate tissue oximeters:

Use the same fundamental optical operating principle, called diffuse । reflectance spectroscopy.
Use light from an LED to probe a cross-section of the microvasculature of tissue (arterioles, capillaries, and venuole).
-Analyze light returning from tissue, after having passed through the tissue, for hemoglobin in its oxygenated and deoxygenated forms in the optically sampled region.
-Calculate StO2%, a value reflecting the percentage saturation of hemoglobin with oxygen in the microvascular capillary spaces

Both T-Stat™ and the predicate pulse oximeters:

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Use the same fundamental optical operating principle, called diffuse reflectance spectroscopy.

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-Analyze light returning from tissue, after having passed through the tissue. for hemoglobin in its oxygenated and deoxygenated forms in the optically sampled region.
| Calculate and display a relative hemoglobin value used for assessment of device functionality, proper probe placement, and system operation.

Both the T-Stat™ and the endoscope predicates:

Emit visible light into the tissues and detect a portion of the light backscattered from tissues in the oral cavity, colon, endoscopic procedures.
। Use low power light that does not adversely influence the physiology of the target tissue.

B. Differences

—

T-Stat™ and the predicate Tissue Oximeters differ in the following nonsignificant ways:

2048 vs. 4 Wavelengths: T-Stat™ measures light at 2,048 wavelengths; the । predicate devices use 4 or fewer wavelengths. An increase in the number of wavelengths used increases the robustness of the matrix solutions by which StO2% is calculated. This is because the solution becomes statistically overdetermined at such large wavelength counts (number of measurements is very much greater than the number of unknowns in the equation).
VLS US NIRS: T-Stat™ uses only visible light (VLS); the predicates use ו both visible and near-infrared light (NIRS). Both methods involve diffuse reflectance spectroscopy; only the wavelength range has changed. Laboratory and clinical values are not changed by the adoption of VLS in favor of NIRS; In vivo, mean VLS StO2% was unbiased compared to NIRS.
-Laser us, Non-Laser LED: T-Stat™ uses a non-laser LED; the predicates use laser LED's. LED choice does not affect the underlying technology of the measurement. The energies emitted by the T-Stat™ non-laser LED and the predicate laser LED's are comparable.

T-Stat™ and the predicate pulse oximeter differ in the following non-significant ways:

Tissue Oximetry: Pulse oximeters estimate arterial saturation, rather than | tissue hemoglobin saturation; however, the predicate for tissue oximetry is

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other tissue oximeters, not pulse oximetry, and therefore this difference is not significant.

T-Stat™ and the predicate endoscopes differ in the following non-significant ways:

-Analysis: Endoscopes typically do not provide spectral analysis; however, the predicate for spectroscopic analysis for hemoglobin saturation is tissue and pulse oximetry, not endoscopy, and therefore this difference is not significant.
C. Result of Comparison

The Spectros T-Stat™ 303 Microvascular Tissue Oximeter is substantially equivalent to the predicate devices.

File Source and Version: T-Stat 510(k) Ch 40 -- Summary (Rev 04.10.28a).doc

[End of Section 40]

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Image /page/5/Picture/1 description: The image shows the seal of the Department of Health & Human Services (HHS) of the United States. The seal features a stylized eagle with three lines forming its body and wings, symbolizing health, hope, and well-being. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular pattern around the eagle.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

NOV - 5 2004

Spectros Corporation c/o David A. Benaron, M.D. CEO & President 4370 Alpine Road, Suite 108 Portola Valley, CA 94028

Re: K040684

K04064
Trade Name: Spectros T-Stat™ 303 Microvascular Tissue Oximeter Regulation Number: 21 CFR 870.2700 Regulation Name: Oximeter Regulatory Class: Class II (two) Product Code: MUD Dated: July 30, 2004 Received: August 9, 2004

Dear Dr. Benaron:

We have reviewed your Section 510(k) premarket notification of intent to market the indication We have reviewed your Section 510(x) prematic is substantially equivalent (for the indications
referenced above and have determined the device is substantially interstate referenced above and have determined the devices marketed in interstate for use stated in the enclosure) to legally manced product and Device Amendments, or to
commerce prior to May 28, 1976, the enactment date of the Federal Food. Drug commerce prior to May 28, 1970, the chactinence with the provisions of the Federal Food. Drug, devices that have been reclassified in accordance while approval application (PMA).
and Cosmetic Act (Act) that do not require approval as provisions of the Act The and Cosmetic Act (Act) that do not require upprovine spension provisions of the Act. The Act. The Act. The You may, therefore, market the device, subject to the genirents for annual registration, listing of
general controls provisions of the Act include required misbranding and general controls provisions of the 7tet merade requirements of the management misbranding and adulteration.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it If your device is classified (see above) mis class a control states on the news can a may be subject to such additional controlis. Existing may on 898. In addition, FDA may
be found in the Code of Federal Regulations, Title 21, Parts 800 to 898 In addition be lound in the Code of I ederal Regarders on the Federal Register.

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Page 2 - Dr. David Benaron

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050. This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Office of Compliance at (301) 594-4648. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html

Sincerely yours,

Bhimmar for

Bram D. Zuckerman, M.D. Director Division of Cardiovascular Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known): K 040684

Device Name: Spectros T-Stat™ 303 Microvascular Tissue Oximeter

Indications For Use: Spectros T-Stat™ 303 Microvascular The Tissue Oximeter is intended for use as an adjunct monitor of the localized hemoglobin oxygen saturation of blood in the microvascular tissue spaces (StO2%) in infants, children, or adults at risk for reduced-flow and no-flow ischemic states.

The prospective clinical value of measurements made with the T-Stat™ Oximeter has not been demonstrated in disease states. The T-Stat™ Oximeter should not be used as the sole basis for diagnosis or therapy.

Prescription Use XXX (Part 21 CFR 801 Subpart D) AND/OR

Over-The-Counter Use (21 CFR 807 Subpart C)

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

Bhimlame

(Division Sign-Off) Division of Cardiovascular Devices neloux 4 510(k) Number

Page 1 of 1

Regulation Number and Section

§ 870.2700 Oximeter.

(a)
Identification. An oximeter is a device used to transmit radiation at a known wavelength(s) through blood and to measure the blood oxygen saturation based on the amount of reflected or scattered radiation. It may be used alone or in conjunction with a fiberoptic oximeter catheter.(b)
Classification. Class II (performance standards).