Patient Monitoring Technical Library

SpO2 Monitoring

Pulse Oximeter Accuracy Study

0 614-902709A
Printed :2014/5/26

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Nihon Kohden commissioned 2 studies to evaluate Nihon Kohden pulse oximeter and probes atthe Hypoxia Research Laboratory, University of California, San Francisco in 2008 and 2010. The
following document is a summarized version of the report from those studies, created by NihonKohden Corporation. This document has been reviewed and approved by the investigators.
This document is owned and controlled by Nihon Kohden and is protected by copyright law.
Use of this document is permitted for personal, non-commercial purposes only.
Modification, reproduction, transmission or distribution of this document is prohibited without priorwritten authorization.
©NIHON KOHDEN CORPORATION. All rights reserved.
Information in this document is true accurate to the best of our knowledge at the time of publication.

SpO2 Accuracy Study ofNihon Kohden Pulse Oximeters

SpO2 Accuracy and Specifications
Pulse oximeters measure oxyhemoglobin saturation (SpO2) from the signals of the red and infrared
light transmitted through the tissue. The theoretical formula for calculating the SpO2 value fromtransmitted light signals is not completely established and each SpO2 manufacturer adopts theirempirically developed calculation method. Therefore, the SpO2 accuracy depends on two factors ofa) the validity of the calculating formula (the calibration curve) and b) deviations from the calculating
formula. For this reason, ISO 80601-2-61: 2011, the International Standard of pulse oximeterequipment, requires each manufacturer to conduct controlled desaturation studies on human subjects
and validate the SpO2 accuracy in comparison to “gold standard (SaO2 value)” which is intended
to include the validation of those two factors previously mentioned. In the ISO 80601-2-61: 2011,the SaO2 value determined by analyzing arterial blood samples with a Hemoximeter is described asreference, and SpO2 accuracy of the pulse oximeter equipment is stated in terms of the RMS (rootmean-square) difference between measured value (SpO2) and reference value (SaO2). This RMS
difference means that two-thirds of the SpO2 values measured by a pulse oximeter can be expected tofall within the range of RMS.
All pulse oximeters and patient monitors with Nihon Kohden SpO2 technology are designed andmanufactured to meet the same specifications for SpO2 measurement accuracy. Nihon Kohden SpO2accuracy is specified below. These specifications exceed the requirements of ISO 80601-2-61: 2011 asnoted.
Table 1. Accuracy criteria for SpO2 measurement
SaO2 range

SpO2 accuracy (RMS)

Nihon Kohden
Pulse Oximeters

80 – 100%2% or less70 – 80%

3% or lessISO 80601-2-61: 201170 – 100%4% or less

Summary of Invasive Controlled Desaturation Study on Healthy Volunteers
Hypoxia Research Laboratory (University of California, San Francisco) conducted 2 studies, one in2008 and another in 2010 using Nihon Kohden pulse oximeters, OLV-3100, as a third party andreported the result.

1SpO2 Monitoring Pulse Oximeter Accuracy Study

During these studies, each subject was induced hypoxia to different arterial oxyhemoglobin
saturation levels between 70% to 100% by controlling the inspired oxygen concentration, the SpO2
readings of pulse oximeters were recorded simultaneously with drawing arterial blood samples,and statistical analysis was performed between the SpO2 readings and SaO2 reference values
from the Hemoximeters. The SaO2 reference values are determined from the readings of the twoHemoximeters.
Exclusion criteria for this statistical analysis were predefined as follows:- Data which drifted 4% or more during the 10 second plateau reading.
- Data where the two Hemoximeter values disagreed to 2% or more.
A summary for the test result is shown below. The test results show that all tested probes meet theaccuracy specifications.
Table 2. SpO2 accuracy (RMS difference) studied byHypoxia Research Laboratory, University of California, San Francisco
SaO2 range

Probe type70 – 80%

80 – 100%

Finger Probe

TL-201T

1.62%

1.07%

Multi-site Y Probe

TL-260T

1.83%

1.56%

Multi-site Y Probe with clipadapter for ear lobe

TL-260T

2.14%

1.62%

Disposable SpO2 Probe

TL-271T

2.05%

1.39%

Finger Probe

TL-631T

2.79%

1.45%

Disposable SpO2 Probe

TL-051S

1.93%

1.59%

Disposable SpO2 Probe

TL-535U

2.01%

1.37%

SpO2 Monitoring Pulse Oximeter Accuracy Study2

Details are given on succeeding pages, “Accuracy Study Report of Nihon Kohden Palse Oximeter(excerpted version)” studied by Hypoxia Research Laboratory, University of California, San Francisco.

June 1, 2013

30614-902709A Nihon Kohden Pulse Oximeter Accuracy StudyNihon Kohden Corporation
Telemetry Technology CenterAccuracy Study Report ofNihon Kohden Pulse Oximeter Report

Hypoxia Research Laboratory
University of California, San Francisco

March 12-13 and April 16, 2008

October 20 and 21, 2010

John R. Feiner, M.D.

Phillip E. Bickler, Ph.D. M.D.

Phillip E. Bickler, Ph.D. M.D.

John R. Feiner, M.D.

John W. Severinghaus, M.D.

0614-902709A Nihon Kohden Pulse Oximeter Accuracy Study

4

Methods
The first study performed March 12-13 and April 16, 2008, included 18 subjects – 5 women and 13
men for four Nihon Kohden oximeter probes, TL-201T, TL-260T, TL-271T, and TL-631T. TL260T was also tested with a clip adapter for ear lobe in 14 subjects – 4 women and 10 men. And
the second study performed October 20 and 21, 2010, included 12 subjects – 7 women and 5 men
for 2 probes, TL-535U and TL-051S. All were on model OLV-3100 oximeters. A radial arterial
cannula was placed in either the left or right wrist of each subject. Blood gas analysis to determine
oxyhemoglobin saturation was performed on two OSM 3® multi-wavelength oximeters (Hemoximeter,Radiometer, Copenhagen). No subject was anemic (Hemoglobin < 10 gm・dl-1).
Each subject had control data taken at the beginning of each experiment, with two control blood
samples drawn while breathing room air. Hypoxia was induced to different levels of oxyhemoglobin
saturation (between 70 - 100%) by having subjects breathe mixtures of nitrogen, room air, and carbon
dioxide. Each plateau level of oxyhemoglobin saturation was maintained for at least 30 seconds
and until pulse oximeters readings had stabilized. Two arterial blood samples were then obtained,
approximately 30 seconds apart. A total of 24 and 20 samples were obtained per subject, respectively,in the first study and the second study. Data were recorded by Nihon Kohden and provided to UCSF
for analysis.

Figure 1. Probes and Pulse Oximeter OLV-3100 used for study

50614-902709A Nihon Kohden Pulse Oximeter Accuracy StudyData Analysis
Data analysis was performed on Excel. Data was excluded if Hemoximeter values disagreed to 2
points or more, or if there was failure to achieve stable pulse oximeter measurements. In the figures,a different marker is used for each study subject. Tables of mean, standard deviation, count and root
mean square are provided for each oximeter’s bias in the following ranges of SaO2 (Hemoximeter): 70- 80%, 80 - 100%. Root mean square error (RMS error) is calculated as follows:

RMSError =∑(SpO2 -SaO2)2
nTable 3 and Table 4 show subject data for the first study. Subject #7 in Table 3 was excluded becauseof an apparent upper respiratory infection. Subject #9 in Table 3 and Subject #6 in Table 5 wasexcluded because the subjects were unable to complete the study.
Table 5 shows subject data for the second study.
Table 3. Subject data for the study for TL-201T, TL-260T, TL-271T, and TL-631T
Subject

Ethnicity

GenderAge

Skin tone

Subject #1

CaucasianM

30

MediumSubject #2

African

M

23

Dark

Subject #3

Asian

M

25

Light

Subject #4

CaucasianF

29

MediumSubject #5

Caucasian

M

22

Light

Subject #6

Caucasian

M

24

Light

Subject #7

Caucasian

M

33

Light

Subject #8

Caucasian

F30

Light

Subject #9

Caucasian

F34

Light

Subject #10

Caucasian

M

28

Light

Subject #11

CaucasianM

22

Light

Subject #12

Indian

F

25

Dark

Subject #13

IndianM

25

MediumSubject #14

African

M

27

Dark

Subject #15

Hispanic/CaucasianF

23

MediumSubject #16

IndianM

21

Med/Dark

0614-902709A Nihon Kohden Pulse Oximeter Accuracy Study

6

Table 4. Subject data for the study for TL-260T with clip adapter for ear lobe
Subject

Ethnicity

GenderAge

Skin tone

Subject #1

CaucasianM

30

MediumSubject #2

IndianM

28

MediumSubject #3

Asian

M

25

Light

Subject #4

CaucasianF

29

MediumSubject #5

Caucasian

M

22

Light

Subject #6

Caucasian

M

24

Light

Subject #7

CaucasianM

33Light

Subject #8

Caucasian

F30

Light

Subject #9

Caucasian

F34

Light

Subject #10

Caucasian

M

28

Light

Subject #11

Caucasian

M

22

Light

Subject #12

Hispanic/CaucasianM

24

MediumSubject #13

IndianM

25

MediumSubject #14

Hispanic/CaucasianF

23

MediumTable 5. Subject data for the study for TL-535U and TL-051S

7

Subject

Ethnicity

GenderAge

Skin tone

Subject #1

HispanicM

28

MediumSubject #2

CaucasianF

28

Light/Medium

Subject #3

Indian

M

27

Dark

Subject #4

Indian

F

28

Dark

Subject #5

Asian

M

26

MediumSubject #6

HispanicM

28

MediumSubject #7

Asian

F

27

MediumSubject #8Caucasian

F23

Light/Medium

Subject #9

Haitian

F29

Dark

Subject #10

Caucasian

M24

Light

Subject #11

HispanicF

25

Light/Medium

Subject #12

Asian

F

24

Light/Medium

0614-902709A Nihon Kohden Pulse Oximeter Accuracy Study

TL-201T Finger Probe
SpO2 accuracy

Table 6. Result for TL-201T Bias (SpO2-SaO2) Analysis
Probe

TL-201T

Hemoximeter SaO2 Range

70 – 80%

80 – 100%

Count

158

464

Mean-0.47%-0.46%

Standard Deviation

1.56%

0.97%

Root Mean Square (RMS)

1.62%

1.07%

Figure 2. TL-201T Bias (SpO2-SaO2)

10Bias SpO2 ‐ SaO2 [%}8Subject 16

Subject 24Subject 4

Subject 3
Subject 52Subject 6Subject 80

Subject 10
Subject 11‐2Subject 12‐4Subject 13
Subject 14‐6Subject 15
Subject 16‐8‐106065707580859095100Hemoximeter SaO2 [%}Pulse Oximeter:OLV-3100
Hemoximeter:OSM 3 ®
Data supply: Hypoxia Research Laboratory, University of California, San Francisco

0614-902709A Nihon Kohden Pulse Oximeter Accuracy Study

8TL-260T Multi-site Y Probe
SpO2 accuracy

Table 7. Result for TL-260T Bias (SpO2-SaO2) Analysis
ProbeTL-260THemoximeter SaO2 Range

70 – 80%

80 – 100%

Count158464

Mean

0.08%

-1.01%

Standard Deviation

1.84%

1.18%

Root Mean Square (RMS)

1.83%

1.56%

Figure 3. TL-260T Bias (SpO2-SaO2)

10Bias SpO2 ‐ SaO2 [%]8Subject 16

Subject 24

Subject 4

Subject 3
Subject 52

Subject 60

Subject 8‐2

Subject 11

Subject 10
Subject 12‐4

Subject 13‐6

Subject 14‐8

Subject 16

Subject 15‐1060

65707580859095

100

Hemoximeter SaO2 [%]Pulse Oximeter:OLV-3100
Hemoximeter:OSM 3 ®
Data supply: Hypoxia Research Laboratory, University of California, San Francisco

90614-902709A Nihon Kohden Pulse Oximeter Accuracy Study

TL-260T Multi-site Y Probe with Clip Adapter for ear lobe
SpO2 accuracy

Table 8. Result for TL-260T with clip adapter for ear lobe Bias (SpO2-SaO2) Analysis
Probe

TL-260T

Hemoximeter SaO2 Range

70 – 80%

80 – 100%

Count136394

Mean

0.20%

0.65%

Standard Deviation

2.14%

1.48%

Root Mean Square (RMS)

2.14%

1.62%

Figure 4. TL-260T with clip adapter for ear lobe Bias (SpO2-SaO2)

108

Subject 1

6

Subject 2
Subject 3

Bias SpO2‐SaO2 〔%〕4Subject 42Subject 5
Subject 60

Subject 8‐2

Subject 10
Subject 11‐4

Subject 12‐6

Subject 13
Subject 14‐8‐106065707580859095100Hemoximeter SaO2 〔%〕Pulse Oximeter:OLV-3100
Hemoximeter:OSM 3 ®
Data supply: Hypoxia Research Laboratory, University of California, San Francisco

0614-902709A Nihon Kohden Pulse Oximeter Accuracy Study

10TL-271T Adult Disposable SpO2 Probe
SpO2 accuracy

Table 9. Result for TL-271T Bias (SpO2-SaO2) Analysis
Probe

TL-271THemoximeter SaO2 Range

70 – 80%80 – 100%Count158464

Mean

0.84%

0.53%Standard Deviation

1.88%

1.29%

Root Mean Square (RMS)

2.05%

1.39%

Figure 5. TL-271T Bias (SpO2-SaO2)

10Bias SpO2 ‐ SaO2 [%]8Subject 16

Subject 24

Subject 4

Subject 3
Subject 52

Subject 60

Subject 8‐2

Subject 11

Subject 10
Subject 12‐4

Subject 13‐6

Subject 14‐8

Subject 16

Subject 15‐106065707580859095

100

Hemoximeter SaO2 [%]Pulse Oximeter:OLV-3100
Hemoximeter:OSM 3 ®
Data supply: Hypoxia Research Laboratory, University of California, San Francisco

110614-902709A Nihon Kohden Pulse Oximeter Accuracy StudyTL-631T Finger Probe
SpO2 accuracy

Table 10. Result for TL-631T Bias (SpO2-SaO2) Analysis
Probe

TL-631T

Hemoximeter SaO2 Range

70 – 80%

80 – 100%Count

158464Mean-1.81%-0.76%

Standard Deviation

2.13%

1.24%

Root Mean Square (RMS)

2.79%

1.45%

Figure 6. TL-631T Bias (SpO2-SaO2)

108

Subject 1
Subject 26

Subject 3
Bias SpO2 ‐ SaO2 [%]4

Subject 4
Subject 52

Subject 6
Subject 80

Subject 10‐2

Subject 11
S bj 12
Subject2‐4

Subject 13
Subject 14‐6

Subject 15‐8

Subject 16‐106065707580859095100Hemoximeter SaO2 [%}Pulse Oximeter:OLV-3100
Hemoximeter:OSM 3 ®
Data supply: Hypoxia Research Laboratory, University of California, San Francisco

0614-902709A Nihon Kohden Pulse Oximeter Accuracy Study

12TL-051S Disposable SpO2 Probe
SpO2 accuracy

Table 11. Result for TL-051S Bias (SpO2-SaO2) Analysis
ProbeTL-051SHemoximeter SaO2 Range

70 – 80%

80 – 100%

Count81178

Mean

0.81%

0.09%

Standard Deviation

1.77%

1.59%

Root Mean Square (RMS)

1.93%

1.59%

Figure 7. TL-051S Bias (SpO2-SaO2)

1086Subject 1
Subject 2Bias SpO2 ‐ SaO2 [%]4Subject 32

Subject 4
Subject 50

Subject 7
Subject 8‐2Subjectj 9‐4Subject 10
Subject 11‐6Subject 12‐8‐106065707580859095100Hemoximeter SaO2 [%]Pulse Oximeter:OLV-3100
Hemoximeter:OSM 3 ®
Data supply: Hypoxia Research Laboratory, University of California, San Francisco

130614-902709A Nihon Kohden Pulse Oximeter Accuracy StudyTL-535U Disposable SpO2 Probe
SpO2 accuracy

Table 12. Result for TL-535U Bias (SpO2-SaO2) Analysis
ProbeTL-535UHemoximeter SaO2 Range70 – 80%80 – 100%

Count

162356

Mean0.72%

0.03%

Standard Deviation

1.88%

1.37%

Root Mean Square (RMS)

2.01%

1.37%

Figure 8. TL-535U Bias (SpO2-SaO2)

108Bias SpO2 ‐ SaO2 [%}6Subject 14

Subject 22

Subject 4

Subject 3
Subject 50

Subject 7‐2

Subject 8‐4Subject 10

Subject 9
Subject 11‐6Subjectj 12‐8‐106065

707580859095100

Hemoximeter SaO2 [%]Pulse Oximeter:OLV-3100
Hemoximeter:OSM 3 ®
Data supply: Hypoxia Research Laboratory, University of California, San Francisco

0614-902709A Nihon Kohden Pulse Oximeter Accuracy Study

14

First Edition:December 19th, 2008
Second Edition: April 1st, 2014

SpO2 Monitoring
Pulse Oximeter Accuracy Study
Patient Monitoring Technical Library

NIHON KOHDEN CORPORATION
1-31-4 Nishiochiai, Shinjuku-ku, Tokyo161-8560, Japan
Phone +81 (3) 5996-8036 Fax +81 (3) 5996-8100

SpO2 Monitoring

Pulse Oximeter Accuracy StudyNIHON KOHDEN CORPORATION

1-31-4 Nishiochiai, Shinjuku-ku, Tokyo 161-8560, Japan
Phone +81 (3) 5996-8036
Fax +81 (3) 5996-8100

http://www.nihonkohden.co.jp/