ISO 81060-2:2009

Non-invasive sphygmomanometers - Part 2: Clinical validation of automated measurement type

ISO 81060-2:2009 is applicable to all sphygmomanometers that sense or display pulsations, flow or sounds for the estimation, display or recording of blood pressure. These sphygmomanometers need not have automatic cuff inflation. ISO 81060-2:2009 covers sphygmomanometers intended for use in all patient populations (e.g. all age and weight ranges), and all conditions of use (e.g. ambulatory blood pressure monitoring, stress testing blood pressure monitoring and blood pressure monitors for the home healthcare environment or self-measurement). ISO 81060-2:2009 specifies additional disclosure requirements for the accompanying documents of sphygmomanometers validated according to this International Standard.

General Information

• Status: Published
• Publication Date: 07-May-2009
• ICS: 11.040.10 - Anaesthetic, respiratory and reanimation equipment
• Technical Committee: SC 62D - Particular medical equipment, software, and systems
• Drafting Committee: JWG 7 - TC 62/SC 62D/JWG 7
• Current Stage: DELPUB - Deleted Publication
• Start Date: 01-May-2013
• Completion Date: 26-Oct-2025

Relations

• Revised: ISO 81060-2:2013 - Non-invasive sphygmomanometers -- Part 2: Clinical investigation of automated measurement type
• Effective Date: 05-Sep-2023

Overview

ISO 81060-2:2009 - "Non‑invasive sphygmomanometers - Part 2: Clinical validation of automated measurement type" specifies how to clinically validate automated non‑invasive blood pressure monitors. It applies to sphygmomanometers that sense or display pulsations, flow or sounds for estimating, displaying or recording blood pressure (automatic cuff inflation is not required). The standard covers devices intended for all patient populations and use conditions (ambulatory monitoring, stress testing, home/self‑measurement) and requires specific disclosures in accompanying documents.

Key topics and technical requirements

• Validation methods: Clinical validation must use either an auscultatory (non‑invasive) reference sphygmomanometer or reference invasive blood pressure monitoring equipment for each device mode.
• Study size and data: An auscultatory validation study requires a minimum of 85 subjects and at least 255 valid paired determinations (typically ≥3 per subject).
• Demographics & distributions: Minimum 30% male and 30% female; age criteria (adults/adolescents >12 years); special provisions for children (3–12 years - 35 child subjects if device intended for children). Detailed blood pressure and limb size distribution requirements ensure coverage across low/high systolic and diastolic ranges and cuff ranges.
• Special populations: Devices intended for populations with potential accuracy issues (e.g., atrial fibrillation, premature ventricular beats, peripheral arterial disease, pregnancy) must be validated in those populations - typically an additional 35 special‑population subjects.
• Observer and measurement protocol: Simultaneous reference measurements by two observers using a double stethoscope; rules for Korotkoff phases (K5 vs K4) and exclusion criteria (e.g., large observer differences, irregular rhythms).
• Ethics and clinical practice: All studies must comply with ISO 14155 (clinical investigation of medical devices - good clinical practice). Validation using invasive reference equipment should not be performed solely for validation purposes.
• Documentation: The standard specifies additional disclosure requirements for the instructions for use and clinical investigation reports.

Practical applications - who uses this standard

• Medical device manufacturers: to design and run clinical validation studies for automated blood pressure monitors and to prepare compliant labeling and instructions for use.
• Clinical researchers and test laboratories: to conduct, audit and report validation studies that meet regulatory and international expectations.
• Regulatory reviewers and procurement teams: to assess device performance claims for approval and selection (home, ambulatory, ICU/OR, stress testing).
• Quality and compliance officers: to align device development and post‑market verification with internationally recognized methods.

Related standards and references

• ISO 81060‑1:2007 (non‑automated measurement requirements)
• IEC 80601‑2‑30:2009 (automated non‑invasive sphygmomanometers - particular safety/performance)
• ISO 14155 (clinical investigation - good clinical practice)
• IEC 60601 series (medical electrical equipment)

Keywords: ISO 81060-2:2009, clinical validation, non-invasive sphygmomanometers, automated blood pressure monitors, validation study, auscultatory reference, invasive reference, cuff size, special patient populations.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 81060-2
First edition
2009-05-01
Non-invasive sphygmomanometers —
Part 2:
Clinical validation of automated
measurement type
Sphygmomanomètres non invasifs —
Partie 2: Validation clinique pour type à mesurage automatique

Reference number
©
ISO 2009
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©  ISO 2009
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ii © ISO 2009 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 General requirements for validation studies .2
4.1 Validation methods. 2
4.2 Ethical requirements . 2
5 Validation with auscultatory reference sphygmomanometer . 2
5.1 Subject requirements . 2
5.2 Validation method with reference sphygmomanometer. 4
6 Validation with reference invasive blood pressure monitoring equipment. 14
6.1 Patient requirements . 14
6.2 Validation methods with reference invasive blood pressure monitoring equipment . 16
7 * Pregnant, including pre-eclamptic, patient populations. 19
Annex A (informative) Rationale . 20
Annex B (normative) Target heart rates for exercise stress testing. 29
Annex C (informative) Reference to the essential principles . 30
Annex D (informative) Terminology — Alphabetized index of defined terms. 32
Bibliography . 33

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 81060-2 was prepared by Technical Committee ISO/TC 121, Anaesthetic and respiratory equipment,
Subcommittee SC 3, Lung ventilators and related equipment and Technical Committee IEC/TC 62, Electrical
Equipment in Medical Practice, Subcommittee 62D, Electromedical Equipment.
ISO 81060 consists of the following parts, under the general title Non-invasive sphygmomanometers:
⎯ Part 1: Requirements and test methods for non-automated measurement type
⎯ Part 2: Clinical validation of automated measurement type
iv © ISO 2009 – All rights reserved

Introduction
Determination of blood pressure is an important procedure that is clinically used to assess the health of the
patient.
Frequent determination of blood pressure is routine during anaesthesia. Blood pressure serves to aid in
drug titration and fluid management and to provide warning of conditions that could affect patient morbidity
and mortality.
In this document, the following print types are used:
⎯ requirements, compliance with which can be verified, and definitions: roman type;
⎯ notes and examples: smaller roman type;
⎯ terms defined in this document: bold type.
Throughout this document, text for which a rationale is provided in Annex A is indicated by an asterisk (*).

INTERNATIONAL STANDARD ISO 81060-2:2009(E)

Non-invasive sphygmomanometers —
Part 2:
Clinical validation of automated measurement type
1 Scope
This part of ISO 81060 specifies the requirements and methods for the clinical validation of me equipment
used for the intermittent non-invasive automatic estimation of the arterial blood pressure by utilizing a cuff.
This part of ISO 81060 is applicable to all sphygmomanometers that sense or display pulsations, flow or
sounds for the estimation, display or recording of blood pressure. These sphygmomanometers need not
have automatic cuff inflation. This part of ISO 81060 covers sphygmomanometers intended for use in all
patient populations (e.g. all age and weight ranges), and all conditions of use (e.g. ambulatory blood
pressure monitoring, stress testing blood pressure monitoring and blood pressure monitors for the home
healthcare environment or self-measurement).
EXAMPLE Automated sphygmomanometer as given in IEC 80601-2-30 validated by this part of ISO 81060.
This part of ISO 81060 specifies additional disclosure requirements for the accompanying documents of
sphygmomanometers validated according to this part of ISO 81060.
This part of ISO 81060 is not applicable to the validation of non-automated sphygmomanometers as given
in ISO 81060-1 or invasive blood pressure monitoring equipment as given in IEC 60601-2-34.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
1)
ISO 14155:— , Clinical investigation of medical devices for human subjects — Good clinical practice
ISO 81060-1:2007, Non-invasive sphygmomanometers — Part 1: Requirements and test methods for non-
automated measurement type
IEC 80601-2-30:2009, Medical electrical equipment — Part 2-30: Particular requirements for basic safety and
essential performance of automated non-invasive sphygmomanometers
IEC 60601-1:2005, Medical electrical equipment — Part 1: General requirements for basic safety and
essential performance
IEC 60601-1-11, Medical electrical equipment — Part 1-11: General requirements for basic safety and
essential performance — Collateral standard: Requirements for medical electrical equipment and medical
electrical systems used in home care applications
IEC 60601-2-34:2000, Medical electrical equipment — Part 2-34: Particular requirements for the safety,
including essential performance, of invasive blood pressure monitoring equipment

1) To be published.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14155, IEC 80601-2-30,
IEC 60601-1, IEC 60601-1-11, IEC 60601-2-34 and the following apply. For convenience, an alphabetized list
of the sources of all defined terms used in this document is given in Annex D.
3.1
reference
established accuracy used for clinical evaluation of other instruments
3.2
sphygmomanometer
me equipment for non-invasive estimation of systemic arterial blood pressure
3.3
sphygmomanometer-under-test
sphygmomanometer being clinically evaluated
4 General requirements for validation studies
4.1 Validation methods
Sphygmomanometers other than non-automated sphygmomanometers shall be clinically validated either
by using a non-invasive (auscultatory) reference sphygmomanometer or by using reference invasive
blood pressure monitoring equipment according to this part of ISO 81060 in each mode of operation.
EXAMPLE 1 Adult and neonatal mode.
EXAMPLE 2 Slow and fast cuff deflation rate mode.
A clinical validation study shall be considered a type test.
Consider compliance with the requirements of this subclause to exist when the criteria of the relevant
inspections and tests in this part of ISO 81060 are met.
4.2 Ethical requirements
All clinical validation studies shall comply with the requirements of ISO 14155. Validation with reference
invasive blood pressure monitoring equipment should not be used for patients or subjects solely for the
purpose of validating sphygmomanometer performance.
NOTE Some authorities with jurisdiction have additional requirements.
Check compliance by application of the requirements of ISO 14155.
5 Validation with auscultatory reference sphygmomanometer
5.1 Subject requirements
5.1.1 * Number
An auscultatory reference sphygmomanometer validation study shall consist of a minimum of 85 subjects. If
not otherwise specified, at least three valid blood pressure determinations shall be taken for each subject.
There shall be a minimum of 255 valid paired blood pressure determinations.
Check compliance by inspection of the clinical investigation report.
2 © ISO 2009 – All rights reserved

5.1.2 * Gender distribution
At least 30 % of the subjects shall be male and at least 30 % of the subjects shall be female.
Check compliance by inspection of the clinical investigation report.
5.1.3 * Age distribution
For a sphygmomanometer intended for use on adults and/or adolescent patients, the ages of the subjects
included in the validation study shall be > 12 y.
NOTE 1 Minimum total of 85 subjects.
For a sphygmomanometer additionally intended for use in children, 35 child subjects aged between 3 y and
12 y shall be included in the validation study.
NOTE 2 Minimum total of 85 subjects.
If the sphygmomanometer has a special mode for children, in that mode, children shall be considered a
special patient population (see 5.1.6). In that mode, children are exempt from the blood pressure distribution
requirements of 5.1.5.
Children < 3 y shall not be included in an auscultatory reference sphygmomanometer validation study.
Check compliance by inspection of the accompanying document and the clinical investigation report.
5.1.4 * Limb size distribution
For a sphygmomanometer intended for use with a single cuff size, at least 40 % of the subjects shall have a
limb circumference which lies within the upper half of the specified range of use of the cuff and at least 40 %
shall have a limb circumference within the lower half. At least 20 % of the subjects should have a limb
circumference which lies within the upper quarter of the specified range of use of the cuff and at least 20 %
should have a limb circumference within the lower quarter.
For a sphygmomanometer intended for use with multiple cuff sizes, each cuff size shall be tested on at
least 1/(2 × n) of the subjects, where n is the number of cuff sizes.
Check compliance by inspection of the accompanying document and the clinical investigation report.
5.1.5 * Blood pressure distribution
At least 5 % of the readings shall have a systolic blood pressure u 100 mmHg.
At least 5 % of the readings shall have a systolic blood pressure W 160 mmHg.
At least 20 % of the readings shall have a systolic blood pressure W 140 mmHg.
At least 5 % of the readings shall have a diastolic blood pressure u 60 mmHg.
At least 5 % of the readings shall have a diastolic blood pressure W 100 mmHg.
At least 20 % of the readings shall have a diastolic blood pressure W 85 mmHg.
Check compliance by inspection of the clinical investigation report.
5.1.6 * Special patient populations
A sphygmomanometer that is intended for use in special patient populations where there is objective
evidence that the accuracy of the sphygmomanometer might be problematic in those patient populations,
shall be clinically evaluated in those patient populations. See also Clause 7.
EXAMPLES Use with patients who have atrial fibrillation (AF), premature ventricular beats and peripheral arterial
disease (PAD).
If the sphygmomanometer has been evaluated according to the requirements of 5.1.1, it shall then be
validated in at least an additional 35 special population subjects. Otherwise, the evaluation in accordance with
the requirements of 5.1.1 shall only consist of subjects from the special population.
The special population shall be defined in clear terms and address the following attributes: gender (see 5.1.2),
age (see 5.1.3), limb size (see 5.1.4) and blood pressure (see 5.1.5). A summary of this information shall be
disclosed in the instructions for use.
Check compliance by inspection of the instructions for use and the clinical investigation report.
5.2 Validation method with reference sphygmomanometer
5.2.1 * Subject preparation
See Reference [32].
Unless otherwise indicated by the instructions for use of the sphygmomanometer-under-test, position the
subject such that the subject:
⎯ is comfortable;
EXAMPLE Comfortably seated with legs uncrossed and feet flat on the floor.
⎯ has the back, elbow and forearm supported;
⎯ has the middle of cuff at the level of the right atrium of the heart.
Recommend that the subject be as relaxed as possible and that they avoid talking during the entire procedure.
Before the first reading is taken, 5 min should elapse.
5.2.2 * Observer preparation
Observers should be trained in using a proper methodology for performing a resting blood pressure
determination by utilizing an accepted clinical protocol for blood pressure measurement. See References [8],
[28], [29], [32] and [45]. They should have sufficient practice in performing blood pressure determinations.
Each observer's recording of observations of the reference sphygmomanometer shall not be visible to the
other observer. The readings of the sphygmomanometer-under-test shall not be visible to either of these
observers.
EXAMPLE 1 Utilizing a third observer for recording the readings of the sphygmomanometer-under-test.
EXAMPLE 2 Utilizing an electronic means for recording the readings of the sphygmomanometer-under-test.
Instruct the observers to determine diastolic blood pressure as the last audible Korotkoff sound (fifth phase
or K5), except in children between 3 y and 12 y, pregnant subjects, and subjects during exercise, where the
fourth phase (K4) is used.
4 © ISO 2009 – All rights reserved

Instruct the observers to use K4 for the determination of diastolic blood pressure when sounds are audible
with the cuff deflated.
Instruct the observers to record which Korotkoff sound has been used for the determination of diastolic blood
pressure.
The Korotkoff sound used for determination of diastolic blood pressure in the clinical validation study shall
be disclosed in the instructions for use of a sphygmomanometer.
EXAMPLE K5 was used on 65 subjects and K4 was used on 20 subjects.
5.2.3 * Reference determination
Two observers shall make simultaneous blood pressure determinations on each subject using a double
stethoscope.
Unless the sphygmomanometer-under-test is intended for use during significantly irregular heart rhythm
and if either observer detects significantly irregular heart rhythm, that determination shall be excluded.
EXAMPLES Bigeminy, trigeminy, isolated VPB, atrial fibrillation.
NOTE 1 Although evaluation of blood pressure in patients with atrial fibrillation is clinically important, there are
currently no generally-accepted guidelines for determining the blood pressure in such individuals.
Any pair of observers' determinations with a difference greater than 4 mmHg shall be excluded. The
observers' individual values of each determination shall be averaged to create the reference blood pressure
determination.
The observer-to-observer differences shall be reviewed after completing a set of pairs of test-reference
determinations. If any determinations are excluded, additional pair(s) of determinations shall be taken to
ensure that the needed number of valid test-reference pairs are available. A maximum of eight pairs of
determinations should be taken.
Use a reference sphygmomanometer that complies with the requirements of ISO 81060-1, except that the
maximum permissible error shall be ± 1 mmHg. Reading of the values on the reference
sphygmomanometer should be as accurate as possible. When reading the value on the reference
sphygmomanometer, the observers should avoid parallax errors. Rounding has a negative effect on the
results of the clinical validation.
NOTE 2 The cuff is considered part of the reference sphygmomanometer. A cuff that does not comply with
ISO 81060-1 cannot be used.
5.2.4 Validation methods
5.2.4.1 Same arm simultaneous method
5.2.4.1.1 * Procedure
This method shall only be used with a sphygmomanometer-under-test:
⎯ that is designed for use on the upper arm;
⎯ where:
⎯ the continuous linear deflation rate is 2 mmHg/s to 3 mmHg/s or
⎯ for a sphygmomanometer-under-test that controls the deflation as a function of the pulse rate, the
deflation rate is between 2 mmHg/pulse and 3 mmHg/pulse.
This method shall only be used when the sphygmomanometer-under-test cuff meets the requirements of
ISO 81060-1.
The sphygmomanometer-under-test shall not deflate prior to the detection of the reference diastolic blood
pressure. The sphygmomanometer-under-test may be modified to meet this criterion.
NOTE Valid same arm simultaneous determinations require the sphygmomanometer-under-test to inflate the cuff
to at least 20 mmHg higher than the actual systolic blood pressure, as determined by the reference
sphygmomanometer, and to at least 20 mmHg below the actual diastolic blood pressure, as determined by the
reference sphygmomanometer.
Perform the following:
a) Have the observers using the reference sphygmomanometer and the sphygmomanometer-under-
test simultaneously determine the subject's blood pressure utilizing the same cuff and inflation/deflation
cycle (see Figure 1).
Key
1 double stethoscope
2 reference sphygmomanometer display
3 sphygmomanometer-under-test
Figure 1 — Illustration of same arm simultaneous method
b) Clear the sphygmomanometer-under-test memory of the previous determination and then wait at least
60 s.
EXAMPLE Switching the power off and on, removing the blood pressure module or issuing a reset command as
methods to clear any memory of the previous determination.
c) These data points are not used in the determination of accuracy.
d) Have the observers using the reference sphygmomanometer and the sphygmomanometer-under-
test simultaneously determine the subject's blood pressure utilizing the same cuff and inflation/deflation
cycle.
e) Wait at least 60 s between determinations.
f) Repeat d) and e) until the needed number of determinations have been performed.
If an individual subject is unstable during the period of the test, two valid determination pairs may be used. In
this case, additional subjects may be used to complete the method. No more than 10 % of the subjects shall
have fewer than three valid determination pairs.
6 © ISO 2009 – All rights reserved

All data from a subject shall be excluded if any two reference systolic blood pressure determinations differ
by more than 12 mmHg or if any two reference diastolic blood pressure determinations differ by more than
8 mmHg.
5.2.4.1.2 * Data analysis
The sphygmomanometer-under-test shall meet the following two criteria.
a) Criterion 1
For systolic and diastolic blood pressures, the mean error of determination, x , of the n individual paired
n
determinations of the sphygmomanometer-under-test and the reference sphygmomanometer for all
subjects shall not be greater than 5,0 mmHg, with a standard deviation, s , no greater than 8,0 mmHg when
n
calculated according to Equation (1) and Equation (2):
n
xp=× −p (1)
()
n ∑ sut ref
ii
n
i=1
n
s=× (2)
xx−
n ∑()n
i
n−1
i=1
where
x
n
is the mean error;
x = p − p of a paired blood pressure determination (sphygmomanometer-under-test −
sut ref
i
ii
reference sphygmomanometer);
i is the index for the individual element;
n is the number of determinations.
and s shall be calculated and expressed to 0,1 mmHg.
x
n
n
EXAMPLE 1 n = 255 for a sphygmomanometer intended for use in adults and/or adolescent patients (an 85 subject
study).
EXAMPLE 2 n = 255 for a sphygmomanometer intended for use in adults and/or adolescents and children aged
between 3 y and12 y (an 85 subject study).
EXAMPLE 3 n = 105 for a sphygmomanometer intended for a special intended use (a 35 subject study). The
sphygmomanometer that has a separate 85 subject study.
b) Criterion 2
For the systolic and diastolic blood pressures for each of the m subjects, the standard deviation, s , of the
m
averaged paired determinations per subject of the sphygmomanometer-under-test and of the reference
sphygmomanometer shall meet the criteria listed in Table 1 when calculated according to Equation (3):
m
s=× (3)
xx−
m ∑ n
()
j
m−1
j=1
where
is the mean error over all subjects (see Equation 1);
x
n
m is the number of subjects;
j is the index for the individual element;
x is calculated from Equation (4).
j
d
xp=×()−p (4)
j ∑ sut ref
kk
d
k=1
where
d is the number of determinations per subject;
k is the index for the individual element.
Table 1 — Averaged subject data acceptance (criterion 2)
Maximum permissible standard deviation, s , as function of mean error,
x
m n
mmHg
x
n
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9
± 0, 6,95 6,95 6,95 6,95 6,93 6,92 6,91 6,90 6,89 6,88
± 1, 6,87 6,86 6,84 6,82 6,80 6,78 6,76 6,73 6,71 6,68
± 2, 6,65 6,62 6,58 6,55 6,51 6,47 6,43 6,39 6,34 6,30
± 3, 6,25 6,20 6,14 6,09 6,03 5,97 5,89 5,83 5,77 5,70
± 4, 5,64 5,56 5,49 5,41 5,33 5,25 5,16 5,08 5,01 4,90
± 5, 4,79 — — — — — — — — —
EXAMPLE For mean error of ± 4,2, the maximum permissible standard deviation is 5,49.
EXAMPLE 4 m = 85 for a sphygmomanometer intended for use in adults and/or adolescent patients (an 85 subject
study).
EXAMPLE 5 m = 85 for a sphygmomanometer intended for use in adults and/or adolescents and children aged
between 3 y and 12 y (an 85 subject study).
EXAMPLE 6 m = 35 for a sphygmomanometer intended for (an additional) special intended use (a 35 subject study).
The sphygmomanometer that has a separate 85 subject study.
EXAMPLE 7 m = 85 for a sphygmomanometer intended only for a special intended use (an 85 subject study).
8 © ISO 2009 – All rights reserved

5.2.4.2 * Same arm sequential method
5.2.4.2.1 Procedure
Perform the following method:
a) Have the observers using the reference sphygmomanometer determine the subject's blood pressure
(see Figure 2).
Key
1 double stethoscope
2 reference sphygmomanometer display
3 reference sphygmomanometer hand pump
4 sphygmomanometer-under-test
Figure 2 — Illustration of same arm sequential method
b) Wait at least 60 s.
c) Have the observers using the sphygmomanometer-under-test determine the subject's blood pressure.
d) Clear the sphygmomanometer-under-test memory of the previous determination and then wait at least
60 s.
EXAMPLE Switching the power off and on, removing the blood pressure module or issuing a reset command as
methods to clear any memory of the previous determination.
e) These data points shall not be used in the determination of accuracy.
f) The starting order [see g)] of sphygmomanometer-under-test and reference sphygmomanometer
determinations shall be alternated between subjects, or a randomizations procedure may be used to
determine the starting order.
g) Have the observers using the reference sphygmomanometer and the sphygmomanometer-under-
test determine the subject's blood pressure sequentially.
h) Wait at least 60 s between each determination.
i) Repeat g) and h) until the needed number of determinations has been performed.
All data from a subject shall be excluded if any two reference systolic blood pressure determinations differ
by more than 12 mmHg or if any two reference diastolic blood pressure determinations differ by more than
8 mmHg.
5.2.4.2.2 Data analysis
The sphygmomanometer-under-test shall meet the following two criteria.
a) Criterion 1
For systolic and diastolic blood pressures, the mean error of determination, x , of the n individual paired
n
determinations of the sphygmomanometer-under-test and the reference sphygmomanometer for all
subjects shall not be greater than 5,0 mmHg, with a standard deviation, s , no greater than 8,0 mmHg when
n
calculated according to Equation (5) and Equation (6):
n
xp=× −p (5)
()
n ∑ sut ref
ii
n
i=1
n
s=× (6)
xx−
n ∑()n
i
n−1
i=1
where
is the mean error;
x
n
x = p − p of a paired blood pressure determination (sphygmomanometer-under-test − reference
i sut ref
sphygmomanometer);
n is the number of determinations.
The p or reference sphygmomanometer determinations shall not be the average of the preceding and
ref
following reference blood pressures. x and s shall be calculated and expressed to 0,1 mmHg.
n n
EXAMPLE 1 n = 255 for a sphygmomanometer intended for use in adults and/or adolescent patients (an 85 subject
study).
EXAMPLE 2 n = 255 for a sphygmomanometer intended for use in adults and/or adolescents and children aged
between 3 y and 12 y (an 85 subject study).
EXAMPLE 3 n = 105 for a sphygmomanometer intended for a special intended use (a 35 subject study).
b) Criterion 2
For the systolic and diastolic blood pressures for each of the m subjects, the standard deviation, s , of the
m
averaged paired determinations per subject of the sphygmomanometer-under-test and of the reference
sphygmomanometer, shall meet the criteria listed in Table 1 when calculated according to Equation (7).
10 © ISO 2009 – All rights reserved

m
s=× (7)
xx−
m ∑()n
j
m−1
j=1
where
is the mean error over all subjects (see Equation 5);
x
n
m is the number of subjects;
x is calculated from Equation (8).
j
d
xp=×()−p (8)
j ∑ sut ref
kk
d
k=1
where d is the number of determinations per subject.
EXAMPLE 4 m = 85 for a sphygmomanometer intended for use in adults and/or adolescent patients (an 85 subject
study).
EXAMPLE 5 m = 85 for a sphygmomanometer intended for use in adults and/or adolescents and children aged
between 3 y and 12 y (an 85 subject study).
EXAMPLE 6 m = 35 for a sphygmomanometer intended for (an additional) special intended use (a 35 subject study).
EXAMPLE 7 m = 85 for a sphygmomanometer intended only for a special intended use (an 85 subject study).
5.2.4.3 Opposite arm simultaneous method
5.2.4.3.1 * Procedure
The starting limb side of the sphygmomanometer-under-test and the reference sphygmomanometer
determinations shall be alternated between subjects.
Perform the following:
a) Have the observers using the reference sphygmomanometer and the sphygmomanometer-under-
test simultaneously determine the subject's blood pressure in opposite arms (see Figure 3).
b) These data points are not used in the determination of accuracy.
c) Clear the sphygmomanometer-under-test memory of the previous determination and wait at least 60 s.
EXAMPLE Switching the power off and on, removing the blood pressure module or issuing a reset command as
methods to clear any memory of the previous determination.
d) Interchange arm sides of the reference sphygmomanometer and the sphygmomanometer-under-test.
e) Wait at least 60 s from the completion of the previous determination.
f) Repeat c) to e) until six paired determinations have been performed.
g) If the determination by the reference sphygmomanometer or the sphygmomanometer-under-test is
not successfully completed, repeat the determination on the same arm sides, i.e., without interchanging
limb sides.
Key
1 double stethoscope
2 reference sphygmomanometer display
3 reference sphygmomanometer hand pump
4 sphygmomanometer-under-test
Figure 3 — Illustration of opposite arm simultaneous method
All data from a subject shall be excluded if the lateral difference of the reference systolic blood pressure
determinations is more than 15 mmHg or the lateral difference of the reference diastolic blood pressure
determinations is more than 10 mmHg.
The lateral difference, LD, is calculated separately for systolic and diastolic blood pressures, according to
Equation (9).
⎛⎞33
⎜⎟
LD=× − (9)
∑∑
PP
ref_Rijref_L
3⎜⎟
ij==11
⎝⎠
where
P and P are reference blood pressure in right (R) limb and left (L) limb, respectively.
ref_Ri ref_Lj
5.2.4.3.2 * Data analysis
The sphygmomanometer-under-test error, x, is computed by taking the difference between the
sphygmomanometer-under-test blood pressure and reference sphygmomanometer blood pressure
and by adding the lateral difference, LD, according to Equation (10) if the sphygmomanometer-under-test
blood pressure was taken in the left arm or by subtracting the lateral difference, LD, according to Equation
(11) if the sphygmomanometer-under-test blood pressure was taken in the right arm.
x = P − P + LD (10)
sut_L ref_R
x = P − P − LD (11)
sut_R ref_L
12 © ISO 2009 – All rights reserved

where P and P are sphygmomanometer-under-test blood pressures in right (R) arm and left (L)
sut_R sut_L
arm, respectively.
The sphygmomanometer-under-test shall meet the following two criteria.
a) Criterion 1
For systolic and diastolic blood pressures, the mean error of determination, x , of the n individual paired
n
determinations of the sphygmomanometer-under-test and the reference sphygmomanometer for all
subjects shall not be greater than 5,0 mmHg, with a standard deviation, s , not greater than 8,0 mmHg when
n
calculated according to Equation (12) and Equation (13).
n
xx=× (12)
i
n ∑
n
i=1
n
s=× (13)
xx−
n ∑()n
i
n−1
i=1
Where n is the number of determinations.
EXAMPLE 1 n = 510 for a sphygmomanometer intended for use in adults and/or adolescent patients (an 85 subject
study).
EXAMPLE 2 n = 510 for a sphygmomanometer intended for use in adults and/or adolescents and children aged
between 3 y and 12 y (an 85 subject study).
EXAMPLE 3 n = 210 for a sphygmomanometer intended for (an additional) special intended use (a 35 subject study).
Criterion 2
For the average of the systolic and diastolic blood pressures for each subject, the standard deviation, s ,
m
of the m averaged paired determinations of the sphygmomanometer-under-test and the reference
sphygmomanometer, per subject, shall meet the criteria listed in Table 1 when calculated according to
Equation (14).
m
s=× (14)
x − x
m n
∑()
j
m−1
j=1
where
m is the number of subjects;
x is the mean error per subject calculated from Equation (15).
j
xx=× (15)
j ∑ k
k=1
EXAMPLE 4 m = 85 for a sphygmomanometer intended for use in adults and/or adolescent patients (an 85 subject
study).
EXAMPLE 5 m = 85 for a sphygmomanometer intended for use in adults and/or adolescents and children aged
between 3 y and 12 y (an 85 subject study).
EXAMPLE 6 m = 35 for a sphygmomanometer intended for (an additional) special intended use (a 35 subject study).
EXAMPLE 7 m = 85 for a sphygmomanometer intended only for a special intended use (an 85 subject study).
5.2.5 * Additional requirements for a sphygmomanometer intended for use in exercise stress testing
environments
For a sphygmomanometer intended for use in exercise stress testing, an additional clinical validation shall
be performed. During this evaluation, the subjects shall be stressed by dynamic (aerobic) exercise on a
bicycle ergometer so as to increase their heart rate from their resting heart rate to a target heart rate of 50 %
to 70 % of their average maximum heart rate (see Annex B). The physical load setting of the ergometer and
target heart rate shall be recorded. The arm used for a determination shall be supported at heart level during
the determination of blood pressure.
The same arm sequential method of 5.2.4.2 shall not be used. The validation study shall consist of a minimum
of 35 subjects. A stress testing study shall be exempt from the blood pressure distribution requirements of
5.1.5. At least 10 % of the subjects shall have a resting systolic blood pressure W 160 mmHg. At least 10 %
of the subjects shall have a resting diastolic blood pressure W 100 mmHg.
Check compliance by inspection of the clinical investigation report.
5.2.6 Additional requirements for a sphygmomanometer intended for use in ambulatory monitoring
For a sphygmomanometer intended for use in ambulatory monitoring, an additional clinical validation shall
be performed. During this evaluation, the subjects shall be stressed by dynamic (aerobic) exercise on a
bicycle ergometer or treadmill so as to increase their heart rate to 10 % to 20 % above their resting heart rate.
The physical load setting of the ergometer and heart rate shall be recorded. The arm used for a determination
shall be supported at heart level during the determination of blood pressure.
The same arm sequential method of 5.2.4.2 shall not be used. The validation study shall consist of a minimum
of 35 subjects. An ambulatory monitoring study shall be exempt from the blood pressure distribution
requirements of 5.1.5. At least 10 % of the subjects shall have a resting systolic blood pressure >
160 mmHg. At least 10 % of the subjects shall have a resting diastolic blood pressure > 100 mmHg.
Check compliance by inspection of the clinical investigation report.
6 Validation with reference invasive blood pressure monitoring equipment
6.1 Patient requirements
6.1.1 Number
A reference invasive blood pressure monitoring equipment validation study shall consist of a minimum of
15 patients. For each patient, no more than 10 valid blood pressure measurements shall be taken. There
shall be a minimum of 150 valid blood pressure measurements in the validation study.
Check compliance by inspection of the clinical investigation report.
6.1.2 * Gender distribution
At least 30 % of the measurements shall be from male patients and at least 30 % of the measurements shall
be from female patients.
Check compliance by inspection of the clinical investigation report.
14 © ISO 2009 – All rights reserved

6.1.3 * Age distribution
6.1.3.1 Sphygmomanometers intended for use in adults, adolescents or children
For a sphygmomanometer intended for use in adult and/or adolescent patients, the ages of the patients
included in the validation study shall be > 12 y.
NOTE 1 Minimum total of 15 subjects.
For a sphygmomanometer additionally intended for use in children, an additional 5 children aged between 3
y and 12 y shall be included in the validation study.
NOTE 2 Minimum total of 20 subjects.
For a sphygmomanometer additionally intended for use in children, the data analysis (see 6.1.1) of adults,
adolescents and children shall be pooled. Children are exempt from the blood pressure distribution
requirements of 6.1.5.
Check compliance by inspection of the accompanying document and the clinical investigation report.
6.1.3.2 Sphygmomanometer for neonatal or infant populations
A sphygmomanometer intended for use in neonates, infants and children of less than 3 years of age, shall
be validated in those patient populations.
The following age or weight ranges are required for a neonatal mode validation study:
⎯ At least 3 patients shall be < 1 000 g in weight.
⎯ At least 3 patients shall be 1 000 g to 2 000 g in weight.
⎯ At least 3 patients shall be > 2 000 g in weight.
⎯ At least 3 patients shall be W to 29 days and < 1 year of age.
⎯ At least 3 patients shall be W 1 year and < 3 years of age.
⎯ The remaining patients may be from any of the above age or weight groups in order to complete the
sample size of 18.
NOTE Minimum total of 18 patients. A patient can be in more than one category simultaneously.
Neonates, infants and children of less than 3 years of age are exempt from the blood pressure distribution
requirements of 6.1.5, the gender distribution requirements of 6.1.2 and the limb size distribution requirements
of 6.1.4.
Check compliance by inspection of the accompanying document and the clinical investigation report.
6.1.4 * Limb size distribution
For a sphygmomanometer intended for use with a single cuff size, at least 40 % of the subjects shall have a
limb circumference that lies within the upper half of the specified range of use of the cuff and at least 40 %
shall have a limb circumference within the lower half.
For a sphygmomanometer intended for use with multiple cuff sizes, at least 1/(2 × n) of the subjects shall be
tested with each cuff size, where n is the number of cuff sizes.
Check compliance by inspection of the accompanying document and the clinical investigation report.
6.1.5 * Blood pressure distribution
At least 10 % of the subjects shall have a systolic blood pressure u 100 mmHg.
At least 10 % of the subjects shall have a systolic blood pressure W 160 mmHg.
diastolic blood pressure u 70 mmHg.
At least 10 % of the subjects shall have a
At least 10 % of the subjects shall have a diastolic blood pressure W 85 mmHg.
These requirements shall be met by calculating the mean of the reference systolic and diastolic blood
pressure measurements taken during the study. Additional reference measurements may be taken prior to
the study to aid in determining inclusion criteria.
Check compliance by inspection of the clinical investigation report.
6.1.6 Special patient populations
A sphygmomanometer that is intended for use in special patient populations where there is objective
evidence that the accuracy of the sphygmomanometer might be problematic in those patient populations
shall be clinically evaluated in those patient populations. See also Clause 7.
EXAMPLES Use with patients who have atrial fibrillation (AF), premature ventricular beats, arteriosclerosis obliterans
(ASO), arterial calcification at the cuff site.
If the sphygmomanometer has been evaluated according to the requirements of 6.1.1, then only seven
additional special population patients shall be included in the validation study. Otherwise, the evaluation in
accordance with the requirements of 6.1.1 shall consist only of patients from the special population.
Check compliance by inspection of the accompanying document and the clinical investigation report.
6.2 Validation methods with reference invasive blood pressure monitoring equipment
6.2.1 * Reference measurement
Use reference invasive blood pressure monitoring equipment that complies with the requirements of
IEC 60601-2-34, except that the maximum allowable error shall be ± 1 mmHg. The resonant frequency and
damping coefficient of the reference invasive blood pressure monitoring equipment shall be characterized.
See References [16] and [42]. The intra-arterial (IA) transducer and the sphygmomanometer-under-test
should both be kept at the level of the right atrium of the heart.
cuff
Unless the sphygmomanometer-under-test is intended for use during a clinically significantly irregular heart
rhythm or if the reference intra-arterial recording indicates the presence of a significantly irregular heart
rhythm, that intra-arterial blood pressure recording and its associated sphygmomanometer-under-test
blood pressure determination shall be excluded. The records of the invasive pressure values shall be
checked for the occurrence of dysrhythmias against the manufacturer's exclusion criteria. The instructions for
use shall indicate that the effectiveness of this sphygmomanometer has not been established in the
presence of any dysrhythmias included in the exclusion criteria. The effect of isolated premature ventricular
beats (VPBs) may be addressed by removing the pressure pulse associated with the VPB and the following
compensatory beat.
EXAMPLES Bigemeny, trigemeny, isolated VPB, atrial fibrillation.
NOTE Although evaluation of blood pressure in patients with atrial fibrillation is clinically important, there are currently
no generally-accepted guidelines for determining the blood pressure in such indivi
...