EN ISO 10993-10:2009

SLOVENSKI STANDARD
01-julij-2009
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SIST EN ISO 10993-10:2003
SIST EN ISO 10993-10:2003/A1:2006
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Biological evaluation of medical devices - Part 10: Tests for irritation and delayed-type
hypersensitivity (ISO 10993-10:2002, including Amd 1:2006)
Biologische Beurteilung von Medizinprodukten - Teil 10: Prüfung auf Irritation und
Allergien vom verzögerten Typ (ISO 10993-10:2002, einschließlich Änderung 1:2006)
Evaluation biologique des dispositifs médicaux - Partie 10 : Essais d'irritation et
d'hypersensibilité retardée (ISO 10993-10:2002, Amd 1:2006 inclus)
Ta slovenski standard je istoveten z: EN ISO 10993-10:2009
ICS:
11.100.20 %LRORãNRRYUHGQRWHQMH Biological evaluation of
PHGLFLQVNLKSULSRPRþNRY medical devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 10993-10
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2009
ICS 11.100.20 Supersedes EN ISO 10993-10:2002
English Version
Biological evaluation of medical devices - Part 10: Tests for
irritation and delayed-type hypersensitivity (ISO 10993-10:2002,
including Amd 1:2006)
Evaluation biologique des dispositifs médicaux - Partie 10 : Biologische Beurteilung von Medizinprodukten - Teil 10:
Essais d'irritation et d'hypersensibilité retardée (ISO 10993- Prüfung auf Irritation und Allergien vom verzögerten Typ
10:2002, Amd 1:2006 inclus) (ISO 10993-10:2002, einschließlich Änderung 1:2006)
This European Standard was approved by CEN on 12 April 2009.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10993-10:2009: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 93/42/EEC on Medical Devices .4
Annex ZB (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 90/385/EEC on Active Implantable Medical Devices .5

Foreword
The text of ISO 10993-10:2002, including Amd 1:2006 has been prepared by Technical Committee
ISO/TC 194 “Biological evaluation of medical devices” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 10993-10:2009 by Technical Committee CEN/TC 206 “Biological
evaluation of medical devices” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by October 2009, and conflicting national standards shall be withdrawn at
the latest by March 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 10993-10:2002.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directives 93/42/EEC on
Medical Devices and 90/385/EEC on Active Implantable Medical Devices.
For relationship with EU Directives, see informative Annex ZA and ZB, which is an integral part of this
document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 10993-10:2002, including Amd 1:2006 has been approved by CEN as a EN ISO 10993-
10:2009 without any modification.
Annex ZA
(informative)
Relationship between this European Standard and the Essential Requirements of
EU Directive 93/42/EEC on Medical Devices

This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide a means of conforming to Essential Requirements of the
New Approach Directive 93/42/EEC on medical devices.
Once this standard is cited in the Official Journal of the European Communities under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the clauses of this
standard given in table ZA confers, within the limits of the scope of this standard, a presumption of conformity
with the corresponding Essential Requirements of that Directive and associated EFTA regulations.
Table ZA — Correspondence between this European Standard and Directive 93/42/EEC on medical
devices
Clause(s)/sub-clause(s) of this Essential Requirements (ERs) of Qualifying remarks/Notes
EN Directive 93/42/EEC
4, 5, 6, 7, 8 and annex A and B Annex I:
7.1, 7.2, 7.5
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within
the scope of this standard.
Annex ZB
(informative)
Relationship between this European Standard and the Essential Requirements of
EU Directive 90/385/EEC on Active Implantable Medical Devices
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide a means of conforming to Essential Requirements of the
New Approach Directive 90/385/EEC on active implantable medical devices.
Once this standard is cited in the Official Journal of the European Communities under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the clauses of this
standard given in table ZB confers, within the limits of the scope of this standard, a presumption of conformity
with the corresponding Essential Requirements of that Directive and associated EFTA regulations.

Table ZB — Correspondence between this European Standard and Directive 90/385/EEC on active
implantable medical devices
Clause(s)/sub-clause(s) of this Essential Requirements (ERs) of Qualifying remarks/Notes
EN Directive 90/385/EEC
4, 5, 6, 7, 8 and annex A and B
Annex I :
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within
the scope of this standard.
INTERNATIONAL ISO
STANDARD 10993-10
Second edition
2002-09-01
Biological evaluation of medical devices —
Part 10:
Tests for irritation and delayed-type
hypersensitivity
Évaluation biologique des dispositifs médicaux —
Partie 10: Essais d'irritation et d'hypersensibilité retardée

Reference number
ISO 10993-10:2002(E)
©
ISO 2002
ISO 10993-10:2002(E)
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ii © ISO 2002 – All rights reserved

ISO 10993-10:2002(E)
Contents Page
Foreword . iv
Introduction. vi
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 2
4 General principles — Step-wise approach . 3
5 Pretest considerations. 4
5.1 General . 4
5.2 Types of material. 4
5.3 Information on chemical composition . 4
5.4 Material characterization . 5
6 Irritation tests . 5
6.1 In vitro irritation tests . 5
6.2 Factors to be considered in design and selection of in vivo tests . 5
6.3 Animal skin irritation test . 6
6.4 Human skin irritation test. 10
7 Delayed hypersensitivity tests. 14
7.1 Choice of test. 14
7.2 Choice of test sample concentrations . 14
7.3 Other important factors affecting the outcome of the test . 14
7.4 Maximization test for delayed hypersensitivity . 15
7.5 Closed-patch test for delayed hypersensitivity . 18
8 Key factors in interpretation of test results. 20
Annex A (normative) Preparation of materials for irritation/sensitization testing. 21
Annex B (informative) Additional irritation tests.23
Annex C (informative) Background information. 41
Bibliography. 45

ISO 10993-10:2002(E)
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 3.
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 part of ISO 10993 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 10993-10 was prepared by Technical Committee ISO/TC 194, Biological evaluation of medical devices.
This second edition cancels and replaces the first edition (ISO 10993-10:1995), which has been technically revised.
ISO 10993 consists of the following parts, under the general title Biological evaluation of medical devices:
 Part 1: Evaluation and testing
 Part 2: Animal welfare requirements
 Part 3: Tests for genotoxicity, carcinogenicity and reproductive toxicity
 Part 4: Selection of tests for interactions with blood
 Part 5: Tests for in vitro cytotoxicity
 Part 6: Tests for local effects after implantation
 Part 7: Ethylene oxide sterilization residuals
 Part 8: Selection and qualification of reference materials for biological tests
 Part 9: Framework for identification and quantification of potential degradation products
 Part 10: Tests for irritation and delayed-type hypersensitivity
 Part 11: Tests for systemic toxicity
 Part 12: Sample preparation and reference materials
 Part 13: Identification and quantification of degradation products from polymeric medical devices
 Part 14: Identification and quantification of degradation products from ceramics
 Part 15: Identification and quantification of degradation products from metals and alloys
iv © ISO 2002 – All rights reserved

ISO 10993-10:2002(E)
 Part 16: Toxicokinetic study design for degradation products and leachables
 Part 17: Establishment of allowable limits for leachable substances
 Part 18: Chemical characterization of materials
Future parts will deal with other relevant aspects of biological testing.
This part of ISO 10993 is a harmonization of numerous standards and guidelines, including BS 5736, OECD
Guidelines, U.S. Pharmacopoeia and the European Pharmacopoeia. It is intended to be the basic document for the
selection and conduct of tests enabling evaluation of irritation and dermal sensitization responses relevant to safety
of medical materials and devices.
Annex A forms a normative part of this part of ISO 10993. Annexes B and C are for information only.

ISO 10993-10:2002(E)
Introduction
This part of ISO 10993 assesses possible contact hazards from chemicals released from medical devices that may
produce skin and mucosal irritation, eye irritation and delayed contact hypersensitivity
Some materials that are included in medical devices have been tested, and their skin or mucosal irritation or
sensitization potential has been documented. Other materials and their chemical components have not been tested
and may induce adverse effects when in contact with biological tissues. The manufacturer is thus obliged to
evaluate each device for potential adverse effects prior to marketing.
Traditionally, small animal tests are performed prior to testing on humans to help predict human response. More
recently, in vitro tests as well as human tests have been added as alternatives. Despite progress and considerable
effort in this direction, a review of findings suggests that currently no satisfactory in vitro test has been devised to
eliminate the requirement for in vivo testing. Where appropriate, the preliminary use of in vitro methods is
encouraged for screening purposes prior to animal testing. In order to reduce the number of animals used, this part
of ISO 10993 presents a step-wise approach, with review and analysis of test results at each stage. An animal test
is usually required prior to human testing.
It is intended that these studies be conducted using Good Laboratory Practice and comply with regulations related
to animal welfare. Statistical analysis of data is recommended and should be used whenever appropriate.
The tests included in this part of ISO 10993 are important tools for the development of safe products, provided that
these are executed and interpreted by trained personnel.

vi © ISO 2002 – All rights reserved

INTERNATIONAL STANDARD ISO 10993-10:2002(E)

Biological evaluation of medical devices —
Part 10:
Tests for irritation and delayed-type hypersensitivity
1 Scope
This part of ISO 10993 describes the procedure for the assessment of medical devices and their constituent
materials with regard to their potential to produce irritation and delayed-type hypersensitivity.
This part of ISO 10993 includes
a) pretest considerations,
b) details of the test procedures, and
c) key factors for the interpretation of the results.
Instructions are given in annex A for the preparation of materials specifically in relation to the above tests.
Supplementary tests which are required specifically for devices used intradermally in the ocular, oral, rectal, penile
and vaginal areas are given in annex B.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 10993. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 10993 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 10993-1:1997, Biological evaluation of medical devices — Part 1: Evaluation and testing
ISO 10993-2, Biological evaluation of medical devices — Part 2: Animal welfare requirements
ISO 10993-9, Biological evaluation of medical devices — Part 9: Framework for identification and quantification of
potential degradation products
ISO 10993-12, Biological evaluation of medical devices — Part 12: Sample preparation and reference materials
ISO 10993-13, Biological evaluation of medical devices — Part 13: Identification and quantification of degradation
products from polymeric medical devices
ISO 10993-14 Biological evaluation of medical devices — Part 14: Identification and quantification of degradation
products from ceramics
ISO 10993-15, Biological evaluation of medical devices — Part 15: Identification and quantification of degradation
products from metals and alloys
ISO 10993-18, Biological evaluation of medical devices — Part 18: Chemical characterization of materials
ISO 10993-10:2002(E)
ISO 14155-1, Clinical investigation of medical devices for human subjects — Part 1: General requirements
ISO 14155-2, Clinical investigation of medical devices for human subjects — Part 2: Clinical investigation plans
3 Terms and definitions
For the purposes of this part of ISO 10993, the terms and definitions given in ISO 10993-1 and the following apply.
3.1
allergen
sensitizer
substance/material which is capable of inducing specific hypersensitivity such that, on subsequent exposure to the
same substance/material characteristic, allergic effects are produced
3.2
blank liquid
solvent portion treated in the same manner as the identical solvent used for the preparation of test samples but
without test material, and which is intended for the determination of a background response of the solvent
3.3
challenge
elicitation
process following the induction phase in which the immunological effects of subsequent exposures in an individual
to the inducing material are examined
3.4
corrosion
slow destruction of the texture or material of a tissue
EXAMPLE The action of a strong irritant.
3.5
delayed-type hypersensitization
induction of specific T-cell mediated immunological memory for an allergen to which an individual is exposed,
resulting in a delayed-type hypersensitivity reaction after secondary contact with the allergen
3.6
dose
quantity to be administered to the test system at one time
3.7
erythema
reddening of the skin or mucous membrane
3.8
eschar
scab or discoloured slough of skin
3.9
induction
process that leads to the de novo generation of an altered state of immunological reactivity in an individual to a
specific material
3.10
irritant
agent that produces irritation
2 © ISO 2002 – All rights reserved

ISO 10993-10:2002(E)
3.11
irritation
localized non-specific inflammatory response to single, repeated or continuous application of a substance/material
3.12
necrosis
death of one or more cells, or portion of tissue or organ, resulting in irreversible damage
3.13
negative control
material or substance which, when tested by the procedure described, demonstrates the suitability of the procedure
to yield a reproducible, appropriate negative, nonreactive or background response in the test system
3.14
oedema
swelling due to abnormal infiltration of fluid into the tissues
3.15
positive control
material or substance which, when tested by the procedure described, demonstrates the suitability of the procedure
to yield a reproducible, appropriate positive or reactive response in the test system
3.16
solvent
material or substance used to moisten, dilute, suspend, extract or dissolve the test substance material
EXAMPLES Chemical, vehicle, medium, etc.
3.17
test material
material, device, device portion or component thereof that is sampled for biological or chemical testing
3.18
test sample
extract or portion of the test material that is subjected to biological or chemical testing
3.19
ulceration
open sore representing loss of superficial tissue
4 General principles — Step-wise approach
The available methods for testing irritation and sensitization were developed specifically to detect skin irritation and
sensitization potential. Other types of adverse affect are generally not predicted by these tests.
This part of ISO 10993 requires a step-wise approach, which shall include one or more of the following:
a) characterization of test material, involving chemical characterization and analysis of the test sample according
to the general principles described in ISO 10993-9, ISO 10993-13, ISO 10993-14, ISO 10993-15 and
ISO 10993-18;
b) literature review, including an evaluation of chemical and physical properties, and information on the irritation
and sensitization potential of any product constituent as well as structurally related chemicals and materials;
c) consideration of in vitro tests in preference to in vivo tests, and replacement of the latter as new in vitro
methods become available and validated. At the present time there are no validated in vitro tests (other than
simple screens) to detect irritants or sensitizers.
d) in vivo animal tests;
ISO 10993-10:2002(E)
NOTE Acute in vivo animal studies are undertaken to test for materials not already classified as severe irritants or
strong sensitizers by step a) or b). Materials that do not demonstrate an acute dermal irritation at single exposure may then
be further evaluated following repeated exposure.
A test of a positive-control substance for skin sensitization [7] shall be run at least every six months by the
testing laboratory to validate the test system and demonstrate a positive response.
e) non-invasive human tests/clinical trials.
If the material has been demonstrated not to be an irritant, a sensitizer or toxic in animals, studies on skin
irritation may then be considered in humans.
5 Pretest considerations
5.1 General
It is important to emphasise that pretest considerations may result in the conclusion that testing for irritation and/or
sensitization is not necessary.
The requirements given in clause 5 of 10993-1:1997 and in the subclauses below apply.
5.2 Types of material
5.2.1 Initial considerations
It shall be taken into consideration that, during manufacture and assembly of medical devices, additional chemical
components may be used as processing aids, e.g. lubricants or mould-release agents. In addition to the chemical
components of the starting material and manufacturing process aids, adhesive/solvent residues from assembly and
also sterilant residues or reaction products resulting from the sterilization process may be present in a finished
product. Whether these compounds pose a health hazard/risk depends on the leakage or degradation
characteristics of the finished products.
5.2.2 Ceramics, metals and alloys
These materials are normally less complex than polymers and biologically derived materials in terms of the number
of chemical constituents.
5.2.3 Polymers
These materials are normally chemically more complex than those in 5.2.1 in terms of composition. A number of
additives may be present and the completeness of polymerization may vary.
5.2.4 Biologically derived materials
These materials are inherently complex in their composition. They often also contain process residues, e.g.cross-
linkers and anti-microbial agents. Biological materials may not be consistent from sample to sample.
The methods in this part of ISO 10993 have not been designed for testing of biologically derived materials and may
therefore be less adequate. For example, the tests in this part of ISO 10993 do not consider cross-species
sensitization.
5.3 Information on chemical composition
5.3.1 General
Full qualitative data on the chemical constituents of the material shall be established. Where relevant to biological
safety, quantitative data shall also be obtained. If quantitative data are not obtained, the rationale shall be
documented and justified.
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ISO 10993-10:2002(E)
5.3.2 Existing data sources
Qualitative and quantitative information on the composition shall be obtained where possible from the supplier of
the starting material.
For polymers this often requires access to proprietary information; provision should be made for the transfer and
use of such confidential information.
Qualitative information about any additional processing additives (for example, mould-release agents) shall also be
obtained from appropriate members of the manufacturing chain, including converters and component
manufacturers.
In the absence of any data on composition, a literature study to establish the likely nature of the starting material
and any additives is recommended to assist in the selection of the most appropriate methods of analysis for the
material concerned.
NOTE The composition of ceramics, metals and alloys may be in accordance with ISO or American Society of Testing
Materials (ASTM) standards and/or may be specified by the user. However, in order to obtain full qualitative and quantitative
details on composition, it may be necessary to request these from the supplier or manufacturer of the starting material and also
from component manufacturers to ensure processing aids are also identified. Material master files held by regulatory authorities
are another source of data, where they are accessible.
5.4 Material characterization
When details of composition are unavailable, or only qualitative information is available, or new or unknown
substances may be expected to develop during the manufacturing process, it may be necessary to undertake
analysis of a material.
Analytical methods appropriate for the material under investigation shall be used. All analytical techniques shall be
justified, validated and reported and, if not already known, the pH of the material (chemical solutions) shall be
measured prior to any in vivo or in vitro testing when possible. Chemical analysis (qualitative as well as
quantitative) of extracts may give useful information. In this context it should also be emphasised that chemical
analysis of the extract may give results that makes testing for irritation and sensitization unnecessary, as
information on irritation and sensitization potential of the compounds present in the extract solution may already be
available.
6 Irritation tests
6.1 In vitro irritation tests
Two in vitro methods, the rat skin Transcutaneous Electrical Resistance (TER) test and the EPISKIN test, have
been internationally validated as alternative tests to assess the skin corrosivity of chemicals. However, no validated
methods to assess skin irritancy yet exist.
National and international organizations continue work to develop and validate in vitro tests for skin irritancy in
parallel with the search for alternative methods; others have been developing methods to quantify the responses of
animals and humans in order to better define endpoints using non-invasive techniques. See C.1.
6.2 Factors to be considered in design and selection of in vivo tests
Irritation testing of medical devices can be performed with the finished product and/or extracts thereof.
Factors affecting the results of irritation studies include the following:
a) the nature of the device used in a patch test;
b) the dose of the test material;
c) the method of application of the test material;
ISO 10993-10:2002(E)
d) the degree of occlusion;
e) the application site;
f) the duration and number of exposures;
g) the techniques used in evaluating the test.
Additional background information is provided in annex C.
While increased flexibility allows the investigator to enhance the sensitivity of the test to suit conditions of use and
population exposure, consistency in procedure contributes to comparability of test results with different materials
and from different laboratories.
Provisions have been included in the test procedures for evaluation of devices and materials that will have
repeated and/or prolonged exposure. The study shall be designed to exaggerate the anticipated contact (time
and/or concentration) in the clinical situation. This shall be borne in mind during interpretation of the result.
If the pH of the test sample is less than or equal to 2 or equal to or greater than 11,5, the material shall be declared
an irritant and no further testing is required. However, experimental evidence suggests that acidity and alkalinity of
the test material are not the only factors to be considered in relation to the capacity of a material to produce severe
injury. The concentration of the test material, its period of contact, and many other physical and chemical properties
are also important.
NOTE For products intended to be used extensively on normal and compromised skin, no substantial risk is normally
accepted; however, many products, in spite of a potential to irritate, are fully acceptable because of their inherent benefit or
intended biological activity.
6.3 Animal skin irritation test
6.3.1 Principle
An assessment is made of the potential of the material under test to produce dermal irritation in a relevant animal
model.
The rabbit is the preferred test animal.
6.3.2 Test material
If the test material is a solid or a liquid, it shall be prepared as specified in annex A.
In order to demonstrate the sensitivity of the assay it is advisable to include, in addition to the negative control, a
positive control on each animal. As there are two test sites and two control sites on each animal, a maximum of two
test materials may be applied together with the control materials, provided that the same vehicle is used.
6.3.3 Animals and husbandry
Healthy young adult albino rabbits of either sex from a single strain, weighing not less than 2 kg, shall be used.
The animals shall be acclimatized and cared for as specified in ISO 10993-2.
If irritation is anticipated, consideration shall be given to testing in one animal first. Unless a well-defined positive
response [score greater than 2 for either erythema or oedema (see Table 1)] is observed, a minimum of two further
animals shall be used. If no response is expected, initial testing may be conducted using three animals. If the
response in the test using the minimum of three animals is equivocal, further testing shall be considered.
6 © ISO 2002 – All rights reserved

ISO 10993-10:2002(E)
6.3.4 Test procedure
6.3.4.1 Preparation of animals
The condition of the skin is a critical factor. Use only animals with healthy intact skin. Fur is generally clipped within
24 h to 4 h of testing on the backs of the animals a sufficient distance on both sides of the spine for application and
observation of all test sites (approximately 10 cm × 15 cm). Fur may be re-clipped to facilitate observation and/or to
accommodate repeated exposures. Depilatories may be used by trained technicians, if the process has been
validated at the testing facility. If repeated exposure is required, follow the procedures in 6.3.4.2, 6.3.4.3 or 6.3.4.4,
repeated for a maximum of 21 days.

Key
1 Cranial end 5 Control site
2 Test site 6 Test site
3 Control site 7 Caudal end
4 Clipped dorsal region
Figure 1 — Location of skin application sites
6.3.4.2 Application of powder or liquid sample
Apply 0,5 g or 0,5 ml of the test material directly to each test skin site as shown in Figure 1. For solid and
hydrophobic materials, there is no need for moistening. If the material is a powder, it should be slightly moistened
with water or other suitable solvent before application (see annex A).
Cover the application sites with a 2,5 cm × 2,5 cm non-occlusive dressing (such as an absorbent gauze patch) and
then wrap the application site with a bandage (semi-occlusive or occlusive) for a minimum of 4 h. At the end of the
contact time, remove the dressings and mark the positions of the sites with permanent ink. Remove residual test
material by appropriate means, such as washing with lukewarm water or other suitable non-irritating solvent, and
careful drying.
6.3.4.3 Application of extracts and extract vehicle
Apply the appropriate extract(s) to the 2,5 cm × 2,5 cm absorbent gauze patches. Use a volume of extract sufficient
to saturate the gauze; generally 0,5 ml per patch. Apply one patch on each side of the animal as shown in Figure 1.
Apply a control patch of gauze moistened with the extract vehicle as indicated in Figure 1.
Cover the application sites with a bandage (semi-occlusive or occlusive) for a minimum of 4 h. At the end of the
contact time, remove the dressings and mark the positions of the sites with permanent ink. Remove residual test
material by appropriate means, such as washing with lukewarm water or other suitable non-irritating solvent and
careful drying.
ISO 10993-10:2002(E)
6.3.4.4 Application of solid sample
Apply the samples of the test material directly to the skin on each side of each rabbit as shown in Figure 1.
Similarly, apply the control samples to each rabbit. When testing solids (which may be pulverised if considered
necessary), the test material shall be moistened sufficiently with water or, where necessary, an alternative solvent,
to ensure good contact with the skin (see annex A). When solvents are used, the influence of the solvent on
irritation of skin by the test material shall be taken into account
Cover the application sites with 2,5 cm × 2,5 cm non-occlusive dressings (such as a gauze patch) and then wrap
the application sites with a bandage (semi-occlusive or occlusive) for a minimum of 4 h. At the end of the contact
time, remove the dressings and mark the positions of the sites with permanent ink. Remove residual test material
by appropriate means, such as washing with lukewarm water or other suitable non-irritating solvent and careful
drying.
6.3.5 Observation of animals
6.3.5.1 General
Use of natural or full-spectrum lighting is highly recommended to visualize the skin reactions. Describe and score
the skin reactions for erythema and oedema according to the scoring system given in Table 1 for each application
site at each time interval, and record the results for the test report.
NOTE Histological or non-invasive techniques of evaluating the skin reaction(s) may assist in certain cases.
6.3.5.2 Single-exposure tests
For single-exposure tests, record the appearance of each application site at 1 h, 24 h, 48 h and 72 h following
removal of the patches. Extended observation may be necessary if there are persistent lesions, in order to evaluate
the reversibility or irreversibility of the lesions. This need not exceed 14 days.
Table 1 — Scoring system for skin reaction
Primary Irritation
Reaction
Score
Erythema and eschar formation
No erythema
Very slight erythema (barely perceptible)
Well-defined erythema
Moderate erythema
Severe erythema (beet-redness) to eschar formation preventing grading
of erythema
Oedema formation
No oedema
Very slight oedema (barely perceptible)
Well-defined oedema (edges of area well-defined by definite raising)
Moderate oedema (raised approximately 1 mm)
Severe oedema (raised more than 1 mm and extending beyond
exposure area)
Total possible score for irritation 8
Other adverse changes at the skin sites shall be recorded and reported.

8 © ISO 2002 – All rights reserved

ISO 10993-10:2002(E)
6.3.5.3 Repeated-exposure tests
Repeated exposure shall only be carried out after completion of an acute single-exposure test (after at least 72 h of
observation).
For repeated-exposure tests, record the appearances of the application site at 1 h after removal of the patches and
immediately prior to the next application. The number of exposures may vary.
After the last exposure, note the appearance of each application site at 1 h, 24 h, 48 h and 72 h following removal
of the patches. Extended observation may be necessary if there are persistent lesions, in order to evaluate the
reversibility or irreversibility of the lesions. This need not exceed 14 days.
6.3.6 Evaluation of results
For single exposure tests, determine the Primary Irritation Index (PII) as follows.
Use only 24 h, 48 h and 72 h observations for calculations. Observations made prior to dosing or after 72 h to
monitor recovery are not used in the determination.
For each animal, add together the Primary Irritation Scores for the test material for both erythema and oedema at
each time point and divide the sum by the total number of observations. (One observation in this context includes
both erythema and oedema at each test site.) When blank liquid or negative control is used, calculate the Primary
Irritation Score for the controls and subtract that score from the score using the test material to obtain the Primary
Irritation Score. Add the scores for each animal and divide the total by the number of animals. This value is the
Primary Irritation Index.
For repeated exposure, determine the Cumulative Irritation Index as follows.
For each animal, add together the Primary Irritation Scores for both erythema and oedema at each time specified.
Divide this total by the total figure of observations to obtain the Irritation Score per animal.
Add together the Irritation Scores of all animals and divide by the total number of animals. This value is the
Cumulative Irritation Index.
The Cumulative Irritation Index is compared to the categories of Irritation Response defined in Table 2 and the
appropriate Response category is recorded for the report.
NOTE The categories of Cumulative Irritation Index are based on the data relating the Primary Irritation Index (PII) for
chemicals in rabbits to the primary irritation response in humans for a number of chemicals that have been tested in both
specie
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