prEN ISO 8637-2

SLOVENSKI STANDARD
01-september-2025
Zunajtelesni pretočni sistemi za čiščenje krvi - 2. del: Zunajtelesni krvni in
tekočinski obtok za hemodializatorje, hemodiafiltre, hemofiltre in
hemokoncentratorje (ISO/DIS 8637-2:2025)
Extracorporeal systems for blood purification - Part 2: Extracorporeal blood and fluid
circuits for haemodialysers, haemodiafilters, haemofilters and haemoconcentrators
(ISO/DIS 8637-2:2025)
Extrakorporale Systeme zur Blutreinigung - Teil 2: Extrakorporaler Blut- und
Flüssigkeitskreislauf bei Hämodialysatoren, Hämodiafiltern, Hämofiltern und
Hämokonzentratoren (ISO/DIS 8637-2:2025)
Systèmes extracorporels pour la purification du sang - Partie 2: Circuits sanguins
extracorporels et liquidiens pour les hémodialyseurs, les hémodiafiltres, les hémofiltres
et les hémoconcentrateurs (ISO/DIS 8637-2:2025)
Ta slovenski standard je istoveten z: prEN ISO 8637-2
ICS:
11.040.20 Transfuzijska, infuzijska in Transfusion, infusion and
injekcijska oprema injection equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 8637-2
ISO/TC 150/SC 2
Extracorporeal systems for blood
Secretariat: ANSI
purification —
Voting begins on:
Part 2: 2025-07-07
Extracorporeal blood and fluid
Voting terminates on:
2025-09-29
circuits for haemodialysers,
haemodiafilters, haemofilters and
haemoconcentrators
Systèmes extracorporels pour la purification du sang —
Partie 2: Circuits sanguins extracorporels et liquidiens pour
les hémodialyseurs, les hémodiafiltres, les hémofiltres et les
hémoconcentrateurs
ICS: 11.040.20
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
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NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
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NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 8637-2:2025(en)
DRAFT
ISO/DIS 8637-2:2025(en)
International
Standard
ISO/DIS 8637-2
ISO/TC 150/SC 2
Extracorporeal systems for blood
Secretariat: ANSI
purification —
Voting begins on:
Part 2:
2025-07-07
Extracorporeal blood and fluid
Voting terminates on:
2025-09-29
circuits for haemodialysers,
haemodiafilters, haemofilters and
haemoconcentrators
Systèmes extracorporels pour la purification du sang —
Partie 2: Circuits sanguins extracorporels et liquidiens pour
les hémodialyseurs, les hémodiafiltres, les hémofiltres et les
hémoconcentrateurs
ICS: 11.040.20
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
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TO SUBMIT, WITH THEIR COMMENTS,
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Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 8637-2:2025(en)
ii
ISO/DIS 8637-2:2025(en)
Contents  Page
Foreword .v
Introduction .vi
1 Scope . 1
2  Normative references . 1
3  Terms and definitions . 2
4  Requirements . 6
4.1 General .6
4.2 Biological safety and haemocompatibility .7
4.3 Sterility .7
4.4 Non-pyrogenicity .7
4.5 Mechanical characteristics .7
4.5.1 Structural integrity.7
4.5.2 Connectors to haemodialyser, haemodiafilter or haemofilter.7
4.5.3 Connectors to vascular access device.10
4.5.4 Connectors to ancillary components .10
4.5.5 Colour coding .10
4.5.6 Access ports .10
4.5.7 Blood pathway volume .11
4.5.8 Air capture chamber fill level .11
4.5.9 Transducer protectors .11
4.6 Functional characteristics .11
4.6.1 General .11
4.6.2 Blood pump system performance .11
4.6.3 Dialysis fluid pump performance . 12
4.6.4 Net fluid removal . 12
4.6.5 Substitution fluid flow rate . 12
4.6.6 Dialysis fluid composition . . 12
4.6.7 Dialysis fluid temperature . 12
4.6.8 Substitution fluid temperature . 12
4.6.9 Fluid path occlusion. 12
4.6.10 Prevention of air infusion . 13
4.6.11 Pressure monitoring . 13
4.6.12 Blood leak detection . 13
4.7 Expiry date . 13
5 Test methods .13
5.1 General . 13
5.2 Biological safety and haemocompatibility .14
5.3 Sterility .14
5.4 Non-pyrogenicity .14
5.5 Mechanical characteristics .14
5.5.1 Structural integrity.14
5.5.2 Connectors to haemodialyser, haemodiafilter or haemofilter. 15
5.5.3 Connectors to vascular access device. 20
5.5.4 Connectors to ancillary components . 20
5.5.5 Colour coding .21
5.5.6 Access ports .21
5.5.7 Blood pathway volume .21
5.5.8 Air capture chamber fill level .21
5.5.9 Transducer protectors . 22
5.6 Functional characteristics . 22
5.6.1 General . 22
5.6.2 Blood pump system performance . 22
5.6.3 Dialysis fluid pump performance . 22

iii
ISO/DIS 8637-2:2025(en)
5.6.4 Net fluid removal . 22
5.6.5 Substitution fluid flow rate . 22
5.6.6 Dialysis fluid composition . . 23
5.6.7 Dialysis fluid temperature . 23
5.6.8 Substitution fluid temperature . 23
5.6.9 Fluid path occlusion. 23
5.6.10 Prevention of air infusion . 23
5.6.11 Pressure monitoring . 23
5.6.12 Blood leak detection . 23
5.7 Expiry date . 23
6  Labelling .24
6.1 Labelling on the device.24
6.2 Labelling on unit protective packaging .24
6.3 Labelling on the outer shipping container .24
6.4 Information to be given in the accompanying documentation . 25
7  Packaging.26
Annex A (informative)  Rationale for the introduction of changes in Mechanical Characteristics
(structural integrity ) .27
Bibliography .28

iv
ISO/DIS 8637-2:2025(en)
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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical committee ISO/TC 150, Implants for surgery, Subcommittee SC 2,
Cardiovascular implants and extracorporeal systems, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 205, Non-active medical devices, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 8637-2:2024), which has been technically
revised.
The main changes are:
— introduction of the link to the ISO 14971 standard;
— added definition of recommended pressure and foreseeable misuse;
— detailing the requirements for the resistance of transducer protectors;
— detailing of the requirements for the procedure to demonstrate the properties required by the standard
for the specified expiration date;
— access ports shall be tested with the largest hypodermic needle, as stated by the manufacturer;
— introduction of an Annex A to explain the changes and describe the further development of the standard
in the context of regulatory requirements;
— editorial adaptions;
A list of all the parts in the ISO 8637 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
ISO/DIS 8637-2:2025(en)
Introduction
This document is concerned with the extracorporeal blood and fluid circuits manufactured for single use
and intended for use in conjunction with haemodialysers, haemodiafilters, haemofilters and heamodialysis
equipment. The requirements specified in this document for the extracorporeal blood and fluid circuits will
help to ensure safety and satisfactory function.
It was not found practicable to specify materials of construction. This document therefore requires only that
materials which have been tested and that the methods and results are made available upon request. There
is no intention to specify, or to set limits on, the performance characteristics of the devices because such
restrictions are unnecessary for the qualified user and would limit the alternatives available when choosing
a device for a specific application. This document therefore requires only that materials have been tested
and that the methods and results are made available upon request.
The dimensions of the connectors intended for connecting the extracorporeal blood and fluid circuits to
a haemodialyser, haemodiafilter or haemofilter have been reviewed to ensure compatibility with these
devices, as specified in ISO 8637-1. The design and dimensions selected are intended to minimize the risk of
leakage of blood and ingress of air. Connectors with either fixed or loose locking shells are permitted.
This document reflects the consensus of physicians, manufacturers and other interested parties for devices
that are approved for clinical use.

vi
DRAFT International Standard ISO/DIS 8637-2:2025(en)
Extracorporeal systems for blood purification —
Part 2:
Extracorporeal blood and fluid circuits for haemodialysers,
haemodiafilters, haemofilters and haemoconcentrators
1 Scope
This document specifies requirements for disposable extracorporeal blood and fluid circuits and accessories
used in combination with haemodialysis equipment intended for extracorporeal blood treatment therapies
such as, but not limited to, haemodialysis, haemodiafiltration, haemofiltration.
This document does not apply to:
— haemodialysers, haemodiafilters or haemofilters;
— plasmafilters;
— haemoperfusion devices;
— vascular access devices.
NOTE 1 Requirements for haemodialysers, haemodiafilters, haemofilters and haemoconcentrators are specified in
ISO 8637-1.
NOTE 2 Requirements for plasmafilters are specified in ISO 8637-3.
2  Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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.
ISO 80369-20, Small-bore connectors for liquids and gases in healthcare applications — Part 20: Common
test methods
EN ISO 11607-1, Packaging for terminally sterilized medical devices - Part 1: Requirements for materials, sterile
barrier systems and packaging systems (ISO 11607-1:2006, including Amd 1:2014)
EN ISO 11607-2, Packaging for terminally sterilized medical devices - Part 2: Validation requirements for
forming, sealing and assembly processes (ISO 11607-2:2006, including Amd 1:2014)
EN ISO 14971, Medical devices - Application of risk management to medical devices (ISO 14971:2000)
EN IEC 60601-2-16:2025, Medical electrical equipment - Part 2-16: Particular requirements for the basic safety
and essential performance of haemodialysis, haemodiafiltration and haemofiltration equipment
IEC 60601-2-16:2018, Medical electrical equipment – Part 2-16: Particular requirements for basic safety and
essential performance of haemodialysis, haemodiafiltration and haemofiltration equipment
ISO 7864, Sterile hypodermic needles for single use — Requirements and test methods
ISO 10993-1, Biological evaluation of medical devices — Part 1: Evaluation and testing within a risk
management process
ISO/DIS 8637-2:2025(en)
ISO 10993-4, Biological evaluation of medical devices — Part 4: Selection of tests for interactions with blood
ISO 10993-11, Biological evaluation of medical devices — Part 11: Tests for systemic toxicity
ISO 11607-1, Packaging for terminally sterilized medical devices — Part 1: Requirements for materials, sterile
barrier systems and packaging systems
ISO 11607-2, Packaging for terminally sterilized medical devices — Part 2: Validation requirements for forming,
sealing and assembly processes
ISO 11737-2, Sterilization of health care products — Microbiological methods — Part 2: Tests of sterility
performed in the definition, validation and maintenance of a sterilization process
ISO 20417, Medical devices — Information to be supplied by the manufacturer
ISO 80369-7, Small-bore connectors for liquids and gases in healthcare applications — Part 7: Connectors for
intravascular or hypodermic applications
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
active medical device
medical device that relies on a source of energy other than that generated by the human body for that
purpose, or by gravity, and which acts by changing the density of that energy or converting that energy
Note 1 to entry: Devices intended to transmit energy, substances or other elements between an active device and the
patient, without any significant change, shall not be deemed to be active devices. Software shall also be deemed to be
an active device.
3.2
air capture chamber
drip chamber
bubble trap
venous and arterial blood chamber
component intended to capture air, and which can also provide compliance to the blood circuit or allow
pressure to be monitored
Note 1 to entry: Air capture chambers can be equipped with a filter that captures blood thrombi.
3.3
arterial pressure
pressure measured in the blood withdrawal segment or line of the extracorporeal blood circuit between the
patient connection and dialyzer connection
Note 1 to entry: The withdrawal segment of the extracorporeal circuit can be referred to as the arterial or blood
access side.
Note 2 to entry: Pressure in the segment of the extracorporeal circuit taking the blood from the patient can be further
differentiated as the pre-pump pressure, which relates to the extracorporeal circuit before the blood pump, and post-
pump pressure, which relates to the segment of the extracorporeal blood circuit between the blood pump and the inlet
to the dialyser.
ISO/DIS 8637-2:2025(en)
3.4
basic safety
freedom from unacceptable risk caused directly by physical hazards when haemodialysis system (3.16) is
used under normal condition and single fault condition
[SOURCE: IEC 60601-1:2020, 3.10]
3.5
blood leak
movement of blood from the blood compartment to the dialysis (3.7) fluid compartment of the dialyzer or
movement from the blood compartment to the environment
[SOURCE: IEC 60601-2-16:2025, 201.3.202]
3.6
blood pathway
internal surfaces of the blood circuit
3.7
dialysis fluid
dialysing fluid
DEPRECATED: dialysate
DEPRECATED: dialysis solution
aqueous fluid made from dialysis water (3.9) containing electrolytes and, usually, buffer and glucose,
which is intended to exchange solutes with blood during haemodialysis (3.14) or haemodiafiltration (3.17)
haemodiafiltration
Note 1 to entry: The term “dialysis fluid” is used throughout this document to mean the fluid [made from dialysis water
(3.9) and concentrates] which is delivered to the haemodialyser or haemodiafilter by a dialysis fluid delivery system.
Note 2 to entry: The dialysis fluid entering the haemodialyser or haemodiafilter is referred to as “fresh dialysis fluid”,
while the fluid leaving the haemodialyser or haemodiafilter is referred to as “spent dialysis fluid”.
Note 3 to entry: Dialysis fluid does not include pre-packaged parenteral fluids used in some renal replacement
therapies, such as haemodiafiltration and haemofiltration (3.9).
[SOURCE: ISO 23500-1:2024, 3.15,]
3.8
dialysis fluid concentrate
mixture of chemicals and water or chemicals in a highly concentrated media which are mixed with dialysis
water (3.9) to produce dialysis fluid (3.7)
Note 1 to entry: Chemicals can also be in the form of a dry powder.
3.9
dialysis water
water that has been treated to meet the requirements of ISO 23500-3 and which is suitable for use in
haemodialysis (3.14) applications, including the preparation of dialysis fluid (3.7) , reprocessing of dialyzers,
preparation of concentrates and preparation of substitution fluid (3.29) for online convective therapies
Note 1 to entry: Ultrapure dialysis water is highly purified dialysis water (<0,1 CFU/ml and < 0,03 EU/ml) that is
produced by some integrated validated systems, such as two stage RO systems with endotoxin filters. Other alternative
design systems can also produce such water prior to mixing with concentrates to produce ultrapure dialysis fluid.
[SOURCE: ISO 23500-1:2019, 3.17]

ISO/DIS 8637-2:2025(en)
3.10
essential performance
performance of a clinical function, other than that related to basic safety (3.4) , where loss or degradation
beyond the limits specified by the manufacturer (3.20) results in an unacceptable risk
Note 1 to entry: Essential performance is most easily understood by considering whether its absence or degradation
would result in an unacceptable risk.
[SOURCE: IEC 60601-1:2020, 3.27]
3.11
extracorporeal blood circuit
disposable circuit with direct contact to blood or blood components, used to perform haemodialysis (3.14) ,
heamodiafiltration and/or haemofiltration (3.18)
Note 1 to entry: The extracorporeal blood circuit can also contain accessory tubing for attaching the extracorporeal
blood circuit to monitors forming part of the haemodialysis system (3.16)
Note 2 to entry: Extracorporeal blood circuits can also be used for other extracorporeal therapies such as
plasmafiltration and plasma adsorption.
3.12
fluid circuit
disposable circuit with indirect or no contact to the blood or blood components, used to perform
haemodialysis (3.14) , haemodiafiltration and/or haemofiltration (3.18)
Note 1 to entry: Fluid circuits can also be used for other extracorporeal therapies such as plasmafiltration and plasma
adsorption.
Note 2 to entry: System components regarding fluid circuit can include dialysis fluid (3.7), dialysis water (3.9) and
concentrates and are covered by the ISO 23500 series.
Note 3 to entry: Dialysis water is defined as water that has been treated to meet the requirements of ISO 23500-3 and
which is suitable for use in haemodialysis applications, including the preparation of dialysis fluid, reprocessing of
dialysers, preparation of concentrates and preparation of substitution fluid (3.29) for online convective therapies (see
ISO 23500-1:2019, 3.17) .
3.13
fluid pathway
internal surfaces of the fluid circuit (3.12)
3.14
haemodialysis
process whereby concentrations of water-soluble substances in a patient's blood and an excess of fluid of
a patient are corrected by bidirectional diffusive transport and ultrafiltration across a semi-permeable
membrane separating the blood from the dialysis fluid (3.7)
Note 1 to entry: This process typically includes fluid removal by filtration. This process is usually also accompanied by
diffusion of substances from the dialysis fluid into the blood.
3.15
haemodialysis equipment
active medical device (3.1) used to perform haemodialysis (3.14) , haemodiafiltration (3.17) and/or
haemofiltration (3.18)
[SOURCE: EN IEC 60601-2-16:2025]
3.16
haemodialysis system
extracorporeal blood and fluid circuits (3.12), in combination with itshaemodialysis equipment (3.15),
haemodialysers, haemodiafilters or haemofilters, and other additional accessory
Note 1 to entry: Haemodialysers, haemodiafilters or haemofilters are covered in ISO 8637-1.

ISO/DIS 8637-2:2025(en)
3.17
haemodiafiltration
process whereby concentrations of water-soluble substances in a patient’s blood and an excess of fluid of a
patient are corrected by a simultaneous combination of haemodialysis and haemofiltration
Note 1 to entry: Diffusive solute removal is achieved using a dialysis fluid (3.7) stream as in haemodialysis (3.14).
Enhanced convective solute removal is achieved by adding ultrafiltration in excess of that needed to achieve the
desired weight loss ; fluid balance is maintained by the infusion of a replacement solution into the blood circuit either
before (pre-dilution haemodiafiltration) or after (post-dilution haemodiafiltration) or a combination of the two (mixed
dilution haemodiafiltration).
[SOURCE: IEC 60601-2-16:2018, 201.3.208] , modified — Note 1 to entry has been added.]
3.18
haemofiltration
process whereby concentrations of water-soluble substances in a patient’s blood and an excess of fluid of a
patient are corrected by convective transport via ultrafiltration and partial replacement by a substitution
fluid (3.29) resulting in the required net fluid removal (3.22)
Note 1 to entry: Convective transport is achieved by ultrafiltration across a high flux membrane. Fluid balance
is maintained by the infusion of a replacement solution into the blood either before the haemofilter (pre-dilution
haemofiltration) or after the haemofilter (post-dilution haemofiltration) or a combination of the two (mixed dilution
haemofiltration).
Note 2 to entry: In haemofiltration, there is no dialysis fluid stream.
[SOURCE: IEC 60601-2-16:2018, 201.3.211, modified — Notes 1 and 2 to entry have been added.]
3.19
labelling
written, printed, graphic or electronic matter that is affixed to the extracorporeal blood and/or fluid circuit
(3.12) packaging and container which is related to identification, technical description and use of the circuit
but excluding shipping documents
3.20
manufacturer
natural or legal person responsible for the design, manufacture, packaging or labelling (3.19) of the
extracorporeal circuit or the fluid circuit , assembling an extracorporeal circuit or a fluid circuit, or adapting
an extracorporeal circuit or a fluid circuit, regardless of whether these operations are performed by that
person or on that person's behalf by a third party
Note 1 to entry: In some jurisdictions, the responsible organization can be considered as a manufacturer when
involved in the activities described.
3.21
maximum recommended pressure
pressure that the disposable can withstand without damage or functional impairment
3.22
net fluid removal
DEPRECATED: weight loss
fluid loss from the patient
[SOURCE: IEC 60601-2-16:2018, 201.3.212]
3.23
non-active medical device
medical device without an integral power source
EXAMPLE A non-active medical device can be a disposable extracorporeal blood and fluid circuits (3.5).

ISO/DIS 8637-2:2025(en)
3.24
protective measure
constructional feature, specifically designed to protect the patient or user against hazardous situations
3.25
pump system
portion of the extracorporeal blood circuit (3.4) and/or the fluid circuit (3.5) that is acted upon by the pumping
mechanisms forming part of the haemodialysis (3.8) machine
3.26
reasonably foreseeable misuse
use of a product or system in a way not intended by the manufacturer (3.20), but which can result from
readily predictable human behaviour
[1]
[SOURCE: EN ISO 14971; ISO/IEC Guide 63:2019 ]
Note 1 to entry: Readily predictable human behaviour includes the behaviour of all types of users, e.g. lay and
professional users.
Note 2 to entry: Reasonably foreseeable misuse can be intentional or unintentional
3.27
rigid material
material with a modulus of elasticity either in flexure or in tension greater than 3 433 MPa e.g. metal, glass,
some fibre-reinforced polymers and high-performance polymers
3.28
semi-rigid material
material with a modulus of elasticity either in flexure or in tension between 700 and 3 433 MPa e.g.
thermoplastics
3.29
substitution fluid
fluid used in haemofiltration and haemodiafiltration treatments which is directly infused into the
extracorporeal circuit as a replacement for the fluid that is removed from the blood by filtration
[2]
[SOURCE: ISO 23500-1:2024 ]
3.30
transducer protector
pressure-transmitting sterile barrier
component of the extracorporeal blood circuit (3.11) and/or the fluid circuit (3.12) that is intended to provide
a sterile interconnection between the extracorporeal circuits and haemodialysis equipment (3.15) while
allowing the pressure within the extracorporeal circuits to be measured by the haemodialysis equipment
3.31
venous pressure
pressure measured in the blood return segment or line of the extracorporeal blood circuit between the
dialyzer connection and patient connection
Note 1 to entry: The return segment of the extracorporeal blood circuit between the dialyser connection and the
patient connection can be referred to as the venous or blood return side.
4  Requirements
4.1  General
Clause 4 gives the requirements for an extracorporeal circuit.
The evaluation of requirements of Clause 4 shall form part of a structured evaluation plan within a risk
management process in accordance with ISO 14971.

ISO/DIS 8637-2:2025(en)
4.2  Biological safety and haemocompatibility
Parts of the disposable circuit that are intended to come into direct or indirect contact with blood shall be
evaluated for freedom from biological hazards in accordance with 5.2. Attention is drawn to the need to
establish whether national standards governing toxicology and biocompatibility testing exist in the country
in which the circuit is produced or to be marketed.
4.3 Sterility
The blood and fluid pathways of the circuit and the internal mating surfaces of all connectors in contact
(directly or indirectly) with blood during use shall be sterile. Conformity shall be verified in accordance with
5.3. Elements of the blood and fluid circuits can have sections that are never in direct or indirect contact to
the blood. Such elements do not require to be sterile.
4.4  Non-pyrogenicity
The blood and fluid pathways of the circuit and the internal mating surfaces of all connectors in contact
with blood during use shall be non-pyrogenic. Conformity shall be verified in accordance with 5.4.
NOTE 1 Pyrogenicity in this context refers to endotoxin mediated pyrogenicity. Material mediated pyrogenicty is
addressed under 4.2.
NOTE 2 Elements of the blood and fluid circuits can have sections that are never in direct or indirect contact to the
blood. Such elements do not require to be non-pyrogenic.
4.5  Mechanical characteristics
4.5.1  Structural integrity
The device shall be capable of withstanding the maximum positive pressure above atmospheric pressure and
the maximum negative sub-atmospheric pressure that can occur in the haemodialysis system in accordance
with the outputs of the manufacturer’s risk management process. Considerations include, but are not limited
to, the type of application, duration of treatment, pressures and temperatures encountered, and foreseeable
misuse. For basic safety, single failure must also be considered in the assessment. Alternatively use the
maximum pressure recommended by the manufacturer to verify structural integrity.
Conformity shall be verified in accordance with 5.5.1.
4.5.2  Connectors to haemodialyser, haemodiafilter or haemofilter
4.5.2.1  General
All connectors that connect haemodialysers, haemodiafilters haemofilters or haemoconcentrators to the
extracorporeal blood circuit shall provide a safe connection. To ensure a safe connection, leakage of air
from the outside or loss of blood to the environment shall be avoided. The degree of acceptable leakage
rate, minimum separation force, minimum separation torque and maximum connection torque at this
position in the haemodialysis system shall be defined in accordance with the outputs of the manufacturer’s
risk management process. Boundary parameters used in tests such as torques, connection forces and
disconnection forces, holding times, and ambient temperatures, shall be considered and defined as part of
the manufacturer's assessment on the use of the product. The selected forces and torques used in tests shall
be representative of the typical physical conditions of users. If necessary, occupational health and safety
guidelines for maximum permissible torques and forces should be taken into account.
4.5.2.2  Dimensional requirements
Except where the haemodialysers, haemodiafilters haemofilters or haemoconcentrators and the
extracorporeal blood circuit are designed as an integral system, the dimensions, and tolerances of the

ISO/DIS 8637-2:2025(en)
connectors to the haemodialysers, haemodiafilters or haemofilter shall conform to the dimensions and
tolerances given in Figure 1 and Table 1. Conformity shall be verified in accordance with 5.5.2.2.
Key
α angle of thread
β angle of thread
γ dimension t
...