SIST EN ISO 21243:2025

SLOVENSKI STANDARD
01-december-2025
Radiološka zaščita - Merila za delovanje laboratorijev, ki izvajajo začetno
citogenetsko oceno prejete doze pri množičnih žrtvah v radioloških ali jedrskih
nesrečah - Splošna načela in uporaba dicentričnega testa (ISO 21243:2022)
Radiation protection - Performance criteria for laboratories performing initial cytogenetic
dose assessment of mass casualties in radiological or nuclear emergencies - General
principles and application to dicentric assay (ISO 21243:2022)
Strahlenschutz - Leistungskriterien für Laboratorien, die zytogenetische Triage zur
Beurteilung von Massenunfällen in radiologischen oder nuklearen Notfällen - Allgemeine
Grundsätze und Anwendung für dizentrisches Prüfverfahren (ISO 21243:2022)
Radioprotection - Critères de performance pour les laboratoires pratiquant l’estimation
dosimétrique préliminaire par cytogénétique en cas d’accident radiologique ou nucléaire
affectant un grand nombre de personnes - Principes généraux et application au test
dicentrique (ISO 21243:2022)
Ta slovenski standard je istoveten z: EN ISO 21243:2025
ICS:
13.280 Varstvo pred sevanjem Radiation protection
27.120.20 Jedrske elektrarne. Varnost Nuclear power plants. Safety
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21243
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2025
EUROPÄISCHE NORM
ICS 13.280; 27.120.20
English Version
Radiation protection - Performance criteria for
laboratories performing initial cytogenetic dose
assessment of mass casualties in radiological or nuclear
emergencies - General principles and application to
dicentric assay (ISO 21243:2022)
Radioprotection - Critères de performance pour les Strahlenschutz - Leistungskriterien für Laboratorien,
laboratoires pratiquant l'estimation dosimétrique die zytogenetische Triage zur Beurteilung von
préliminaire par cytogénétique en cas d'accident Massenunfällen in radiologischen oder nuklearen
radiologique ou nucléaire affectant un grand nombre Notfällen - Allgemeine Grundsätze und Anwendung für
de personnes - Principes généraux et application au dizentrisches Prüfverfahren (ISO 21243:2022)
test dicentrique (ISO 21243:2022)
This European Standard was approved by CEN on 22 September 2025.

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-CENELEC 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-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21243:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 21243:2022 has been prepared by Technical Committee ISO/TC 85 "Nuclear energy,
nuclear technologies, and radiological protection” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 21243:2025 by Technical Committee CEN/TC 430 “Nuclear
energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.
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 March 2026, and conflicting national standards shall
be withdrawn at the latest by March 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
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,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 21243:2022 has been approved by CEN as EN ISO 21243:2025 without any modification.

INTERNATIONAL ISO
STANDARD 21243
Second edition
2022-11
Radiation protection — Performance
criteria for laboratories performing
initial cytogenetic dose assessment
of mass casualties in radiological
or nuclear emergencies — General
principles and application to dicentric
assay
Radioprotection — Critères de performance pour les laboratoires
pratiquant l’estimation dosimétrique préliminaire par cytogénétique
en cas d’accident radiologique ou nucléaire affectant un grand
nombre de personnes — Principes généraux et application au test
dicentrique
Reference number
ISO 21243:2022(E)
ISO 21243:2022(E)
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 21243:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Responsibility of the laboratory . 3
4.1 Awareness of this document . 3
4.2 Biological dosimetry request and confidentiality . 3
4.3 Pre-planning . 4
4.4 Responsibility during service . 4
5 Biological dosimetry process in radiological or nuclear mass-casualty incidents .5
6 Emergency response of the lead laboratory . 5
7 Design of a laboratory network .5
7.1 Overview . 5
7.2 Preparedness of the laboratory network . 6
7.3 Laboratory network operation . 6
7.3.1 General . 6
7.3.2 Lead laboratory responsibilities . 7
7.3.3 Associate laboratory responsibilities . 7
8 Expected results . 8
8.1 General . 8
8.2 Whole-body exposure . 8
8.3 Inhomogeneous exposure . 9
9 Quality assurance and quality control . 9
9.1 Overview . 9
9.2 Quality control . 10
9.2.1 General . 10
9.2.2 Quality control procedures . 10
9.2.3 Performance checks of sample transport integrity . 10
9.2.4 Performance checks of sample integrity by the laboratory . 10
9.2.5 Performance checks of instrumentation . 10
9.2.6 Performance checks of sample protocol . 11
9.2.7 Performance checks of exposure categorization . 11
9.2.8 Performance checks of sample scoring . 11
9.2.9 Performance checks of dose and confidence intervals estimation . 11
9.2.10 Performance checks of the generation of reports results . 11
9.2.11 Performance checks of a data security plan . 11
9.2.12 Performance of the network .12
Annex A (informative) Interactions between requestors and biological dosimetry
laboratories .13
Annex B (informative) Guidance for threshold of detection when the dicentric assay is
analysed using manual scoring procedures .15
Annex C (informative) Example group sample report .16
Bibliography .18
iii
ISO 21243:2022(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.
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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 2,
Radiological protection.
This second edition cancels and replaces the first edition (ISO 21243:2008), which has been technically
revised.
The main changes are as follows:
— Annex D (Estimates of dose and 95 % confidence limits for selected observations of numbers of
dicentrics and cells) has been removed;
— in 8.1, General: the number of cells to be scored has been moved to Annex B;
— in 8.2, Whole body exposure: addition of a description of when not to assume an acute exposure by
looking at the variance/mean and a phrase stating that for low LET radiation doses below ~0.3Gy,
linearity can be assumed (as with high LET).
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.
iv
ISO 21243:2022(E)
Introduction
The potential for nuclear and radiological emergencies involving mass casualties from accidental or
malicious acts recommends generic procedures for initial dose assessment to help the development of
medical response capabilities. A mass-casualty incident is defined here as an event that exceeds the
local medical resources. Biological dosimetry, based on cytogenetic analysis using the dicentric assay,
typically applied for accidental dose assessment, has been defined in ISO 19238. Initial assessment refers
to an expedited version of the dicentric assay that evaluates chromosome damage in a small number of
cells and would be used in an emergency situation where rapid analysis is needed. This results in an
estimated dose with high uncertainty but allows for exposure categorization. This document focuses
on the use of the dicentric assay for initial cytogenetic analysis in the case of mass-casualty incidents.
Many of the concepts discussed here can be applied to other biological dosimetry methods. The initial
dose evaluation/categorization performed according to this document can be complemented by a more
detailed analysis to reduce uncertainties according to ISO 19238 recommendations.
After a large-scale radiation emergency or malevolent act involving radioactive materials, physicians
are primarily concerned with preserving life and evaluating medical signs and symptoms for early
treatment decisions. It is expected that patients have already been assessed clinically and triaged on
the basis of any prodromal signs and symptoms of overexposure plus available information concerning
their involvement in the incident. In this early-response phase of a radiological or nuclear emergency,
the purpose of cytogenetic assessment is to quickly estimate the absorbed radiation dose for each
referred patient to supplement such early clinical assessment.
The role of this cytogenetic assessment is to confirm whether displayed symptoms can be attributed
to radiation exposure or due to an unrelated cause. It is expected that the cytogenetic report be
sufficiently informative to provide guidance to medical staff as they proceed with clinical management
of the patients. This management can potentially include expedited identification of: (1) concerned,
but not radiation-exposed public, through provision of advice and reassurance; (2) low/moderately
irradiated patients, who do not need out-patient observation or clinical intervention; and (3) highly
irradiated patients requiring active treatment for potentially life-threatening injury through optimized
use of limited medical resources.
Several clinical triage systems have been developed in which irradiated patients are allocated to dose
ranges (or acute-radiation-sickness response categories) based on the severity of prodromal symptoms
that correspond with mild to very severe injuries. Enough experience in using clinical triage schemes
(e.g. from Chernobyl) has been gained to show that the early sorting of persons into these dose or
response category cohorts was adequate for the emergency planning of the patients’ management.
However, as time progresses clinicians are looking for more accurate estimations of doses both in the
low-dose range, where irradiated persons require counselling on risks of late stochastic effects, and
also for higher doses, for anticipating the shorter-term sequelae of severe tissue reactions.
It should be noted that the initial clinical triage interprets the symptoms in terms of the early phase
response to partial or whole-body exposure. Protracted and fractionated exposures need higher doses
in order to produce the same severity of responses.
It is expected that the cytogenetic methods achieve an initial estimate of dose or response category that
is quantitatively more precise than the clinically derived categories, and take into account any evidence
that the exposure might not have been received acutely or to the whole body. It is expected that the
need for precision be set against the competing requirement for expedited results and it is necessary
that this judgement be made at the time of the event. This will depend on the anticipated number of
patients, the surge capacity of the laboratory and the rate at which the blood samples are received by
the laboratory.
Expert cytogenetic biological dosimetry laboratories typically function to support national radiation
protection programmes and emergency response schemes. Several of these national cytogenetic
biological dosimetry laboratories have independently and successfully performed initial dose
assessment in actual and simulated mass-casualty incidents. Their approaches included pre-planning,
reagent stockpiling, simplified sample processing, automation, as well as modifying some of the
ISO 19238 scoring criteria. Several of these national cytogenetic biological dosimetry laboratories
v
ISO 21243:2022(E)
have established networks of supplementary, satellite cytogenetic laboratories, both nationally as
well as internationally. Building upon their experience, this document is intended to define criteria for
performing quality-assured initial assessment of radiation dose using cytogenetic methods.
The primary purpose of this document is to provide a guideline to all biological dosimetry laboratories
for performing the dicentric assay for initial dose assessment using documented and validated
procedures. Secondly, it can facilitate the involvement of cytogenetic biological dosimetry networks
to increase analysis capacity while ensuring dose estimates provided by the network laboratories
are valid. Finally, it is expected that laboratories that are newly commissioned to carry out the initial
cytogenetic analysis conform to this document in order to ensure reproducible and accurate dose
assessments.
This document is written outlining the procedures for the dicentric assay specific to initial biological
dosimetry assessments for potential overexposures involving mass radiological/nuclear casualties.
These procedures can also be applied to other biological dosimetry methods such as the cytokinesis
blocked micronucleus (CBMN) assay as described in ISO 17099. If appropriate, semi-/automation
procedures can be included in the process as long as they have been well validated and described by
the laboratory applying them. The criteria for selecting the level of scoring usually depends on the
application of the results (e.g. medical management, radiation-protection management, record keeping
and medical/legal requirements). For example, selected cases can have more cells analysed to produce
a more accurate evaluation of high partial-body exposure; secondly, doses can be estimated for persons
exposed to doses below the threshold for acute tissue reactions, by using the ISO 19238 criteria. These
latter data also assist in counselling for the risk of late stochastic disease.
Part of the information presented in this document can be found in other international guidelines
and scientific publications, primarily in ISO 19238 and the 2011 of International Atomic Energy
[1]
Agency’s EPR-Biodosimetry publication . However, this document details and standardizes the
quality assurance and quality control of performance criteria for cytogenetic assessment of individual
exposures in radiological or nuclear mass casualty events. This document is generally compliant with
[2]
ISO/IEC 17025 , with particular consideration given to the specific needs of initial biodosimetry.
The expression of uncertainties in dose estimations given in this document conforms with the
[3] [4]
ISO Guide 98 and ISO 5725 (all parts) .
vi
INTERNATIONAL STANDARD ISO 21243:2022(E)
Radiation protection — Performance criteria for
laboratories performing initial cytogenetic dose
assessment of mass casualties in radiological or nuclear
emergencies — General principles and application to
dicentric assay
1 Scope
The purpose of this document is to give an overview of the minimum requirements for performing the
dicentric assay with quality control measures using mitogen stimulated peripheral blood lymphocytes
for initial assessment of individuals involved in a mass casualty scenario. The dicentric assay is the
use of chromosome damage to quickly estimate approximate radiation doses received by individuals in
order to supplement the early clinical categorization of casualties.
This document focuses on the organizational and operational aspects of applying the dicentric assay in
an initial assessment mode. The technical aspects of the dicentric assay can be found in ISO 19238.
This document is applicable either to an experienced biological dosimetry laboratory working alone or
to a network of collaborating laboratories (as defined in Clause 7).
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 for 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 19238, Radiological protection — Performance criteria for service laboratories performing biological
dosimetry by cytogenetics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19238 and the following 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
absorbed dose
D
differential quotient of ε with respect to m, where ε is the mean energy imparted by ionizing radiation
to matter of mass m:
dε
D=
dm
Note 1 to entry: The gray is a special name for joule per kilogram and is to be used as the coherent SI unit for
absorbed dose.
[SOURCE: ISO/IEC 80000-10, 10.81.1]
ISO 21243:2022(E)
3.2
associate laboratory
laboratory that has previously been validated through proficiency testing (3.13) and is prepared to be
contacted for assistance when the capacity of the lead laboratory is exceeded
3.3
biological dosimetry
assessment of the absorbed dose of ionizing radiation using indicators found in biological material,
particularly peripheral blood
3.4
calibration curve
graphical or mathematical description of the dose-effect relationship derived by the in vitro (3.10)
irradiation of blood samples to known physically delivered doses, and the uncertainties associated
with these
Note 1 to entry: The curve is used to determine, by interpolation, the absorbed dose to a potentially exposed
individual.
3.5
chromosome aberration
change in the normal structure of a chromosome involving both chromatids of a single chromosome at
the same locus as observed in metaphase
3.6
cytogenetics
study of the structure of chromosomes
3.7
deterministic effect
biological (health) effect of radiation for which a threshold level of dose exists above which the severity
of the effect is greater for a higher dose
[SOURCE: IAEA. IAEA Safety Glossary: 2018 edition. Vienna: IAEA, 2019]
3.8
fractionated exposure
exposure to ionizing radiation that has been divided into smaller exposures separated in time
3.9
inhomogeneous exposure
exposure that is not received uniformly over the whole body or is received only by part of the body
3.10
in vitro
technique performed in a controlled environment outside of a living organism
3.11
lead laboratory
designated laboratory primarily responsible to lead the coordination of the biodosimetric response in
an emergency
Note 1 to entry: Previously referred to as a reference laboratory.
3.12
network
group of lead and associate cytogenetic laboratories trained and prepared to jointly respond to a
large-scale radiological or nuclear emergency requiring biological dosimetry (3.3)
ISO 21243:2022(E)
3.13
proficiency test
evaluation of participant performance against pre-established criteria by means of inter-laboratory
comparisons
3.14
prodromal
early signs and symptoms indicative of the imminent development of the full manifestation of a disease
or illness, in this case related to radiation exposure
EXAMPLE Diarrhea, nausea, vomiting.
3.15
protracted
dose received over a long period of time
3.16
ring
aberrant circular chromosome resulting from the joining of two breaks within one chromosome
Note 1 to entry: Rings can be centric or acentric.
3.17
stochastic effect
radiation induced health effect, the probability of occurrence of which is greater for a higher radiation
dose and which severity, if it occurs, is independent of dose
Note 1 to entry: Stochastic effects may be somatic effects or hereditary effects, and generally occur without a
threshold level of dose. Examples include solid cancers and haematologic cancers (leukaemia and lymphoma).
[SOURCE: IAEA. IAEA Safety Glossary: 2018 edition. Vienna: IAEA, 2019. 278]
4 Responsibility of the laboratory
4.1 Awareness of this document
It is necessary that local, state, and federal governments’ health care providers and facilities be aware
of the existence of the cytogenetic biological dosimetry programme for individual dose assessment
in radiological or nuclear mass casualty events as established in this document. This is critical for
the laboratory to be able to receive blood samples promptly and thereby provide an initial biological
dosimetry response within the time frame that is clinically useful in order to mitigate the acute health
effects. Qualified laboratories and health care facilities should ensure their organizations, roles and
responsibilities are well defined within radiation emergency concepts of operations at local and
national levels.
4.2 Biological dosimetry request and confidentiality
Biological dosimetry investigations made by lead or associate laboratories shall be undertaken
in accordance with the national regulations regarding confidentiality. This normally includes the
maintenance of confidentiality of the patient’s identity and medical data.
This requirement extends to
a) all written, electronic or verbal communications between the laboratory(ies) and the person or
organization requesting the analysis and receiving the report,
b) protection of confidential information held within the organization where the laboratory is located,
and
c) electronic record management.
ISO 21243:2022(E)
Users with different access restrictions should have different privileges within the system as
appropriate. The laboratory head assigns rights and access restrictions to the rest of the laboratory.
4.3 Pre-planning
Qualified laboratories shall be organized and operate in such a way that, upon receiving a request from
the state/health care facility/hospital for biological dosimetry response, they can quickly and efficiently
provide initial individual dose estimates. The laboratory’s organization shall be clearly predefined and
documented.
Each laboratory shall be responsible for
a) maintaining documentation, which includes the following:
1) an instruction sheet to be sent to the local, regional, national health-care facilities describing
blood drawing requirements and shipping procedures (see ISO 19238:2014, Annex A);
2) a questionnaire that shall elicit patient consent (if required) and information on whole or
partial body exposure, source and quality of the radiation, circumstances of the exposure,
exposure location (country, city, company, etc.), date and time of exposure, previous
occupational or medical exposures to radiation, intake of pharmaceuticals, infection, smoking
habits, and significant exposures to any other DNA damaging agents (such as organic solvents
or heavy metals) (see ISO 19238:2014, Annex B) or any other relevant information regarding
the suspected or confirmed exposure;
b) maintaining a stockpile of its own reagents or having immediate access to reagents and supplies
from a local, state or national stockpile or commercial entity for receiving blood samples, culturing
lymphocytes, preparing metaphase spreads and analysing samples for cytogenetic biological
dosimetry; these include general laboratory supplies as well as reagents and supplies specific to
cytogenetic protocols;
c) maintaining the anonymity of samples. To avoid the identification of the patient while guaranteeing
the traceability of the analysis, the blood samples should be coded upon arrival in the laboratory.
The coding is performed in an unambiguous way according to a standard procedure. The same
code shall be used for all the stages of the analysis. The code is assigned by a designated person.
The decoding, interpretation of results and compiling of the report shall also be performed by a
designated person. If it is required to share a sample, the same code shall be used by all associate
laboratories and for communication between them.
[6]
d) considering to join a network for assistance in case of a large scale emergency situation .
4.4 Responsibility during service
Qualified laboratories shall be responsible for
a) providing the following to local, regional, national health-care facilities:
1) guidance on the appropriateness of the biological dosimetry assay,
2) information on the laboratory’s capabilities in order to select an appropriate cohort of
individuals whose treatment can benefit from cytogenetic biological dosimetry,
3) information to help determine the medical consequences for individuals exposed to radiation;
b) maintaining established communication links with the local/state/federal health care facilities;
c) requesting or recommending activation of a biological dosimetry network when necessary;
d) specifying and documenting the responsibilities, roles and interrelations of all personnel whose
laboratory functions affect the quality of initial biological dosimetry response;
ISO 21243:2022(E)
e) receiving appropriate samples, preparing and analysing samples, providing initial dose assessment
or exposure categorization, and archiving samples or slides;
f) tracking, prioritizing (based upon rapid screening or input from requestors), determining the
appropriate tests and reprioritizing as the tests progress or as additional information is received;
g) reporting results in a timely manner according to the needs of the incident (e.g. faster reporting
of results related to samples from individuals indicating a requirement for urgent clinical
intervention);
h) retaining the responsibility for safety and quality assurance (see Clause 9).
5 Biological dosimetry process in radiological or nuclear mass-casualty
incidents
See Annex A for an example of a flow diagram indicating the interactions between requestors and
biological dosimetry laboratories for different numbers of samples.
6 Emergency response of the lead laboratory
The head of the laboratory shall have an emergency response plan in place, so that all members of the
staff know their role.
By default or without additional information, the dicentric assay is the method-of-choice for radiation
dose estimation. Other methods can be used where appropriate, based on available information about
the accident. The decision to use another method should be documented and made based on a discussion
between the head of the laboratory and other qualified emergency response management personnel.
Where possible, blood samples from the most seriously irradiated persons based on clinical symptoms
or physical dosimetry (when such information is available) are prioritized for processing and analysis.
In the absence of such information, the laboratory processes the blood samples in the order of their
arrival.
The biological dose estimate(s) is(are) obtained from appropriate, robust calibration curve previously
established by the individual network members. An exposure categorization is determined from the
appropriate predefined procedures.
Organization of the workflow should be such that the results of biological dosimetry analyses are
available as soon as possible.
According to the country and the emergency, blood samples should either
— arrive directly at the laboratory where all the processing for cytogenetic analysis occurs; or
alternatively,
— be initially processed in a specialized associate laboratory in, for example, a hospital or research
institute that is already linked through the network to the lead laboratory.
7 Design of a laboratory network
7.1 Overview
A cytogenetic biological dosimetry laboratory network is comprised of a lead laboratory and associate
laboratories that serve as network partners to assist with the response.
In the case of an emergency incident, the lead laboratory (the laboratory that takes primary
responsibility for the response) shall be a selected, qualified and validated laboratory, preferably from
the country where the radiological emergency occurred. When the biological dosimetry capacity of
ISO 21243:2022(E)
the lead laboratory reaches a threshold, activation of the network laboratories might be required to
increase the capacity in order to assess the dose of all potentially exposed individuals.
Laboratories should be prepared to assist in cases where the event takes place in a country that lacks
a biological dosimetry laboratory to lead the efforts. In this case, emergency officials may contact a
biological dosimetry laboratory that is prepared and willing to assist. This laboratory would then
become the lead laboratory for that event, coordinating the response and activating a network if
necessary.
The number of laboratories in a network depends on both the needs specific to the emergency scenario
and the availability of associate laboratories. The associate laboratories are called upon for assistance
by the lead laboratory. The formation of the laboratory network is based on a voluntary and consensual
participation of laboratories qualified in the selected cytogenetic techniques as determined by training
and intra- or inter-laboratory comparisons. The associate laboratories can be from within or outside
the country where the emergency has taken place.
[6]
To be operational, a network shall be prepared in advance as outlined in 4.4 . However, beyond the
requirements of the laboratories acting either as the lead laboratory or an associate laboratory within
the network, the formation and operability of a network is beyond the scope of this document.
7.2 Preparedness of the laboratory network
To be fully operational, the established laboratories willing to be part of a network should have the
following documents ready and available to all network members:
— full contact details (addresses, phones, telefax, e-mail) of the laboratory staff who are involved in
the network together with a mutually agreed process to rapidly activate the network;
— documentation as described in 4.3;
— a description of the technique(s) used, together with details of established radiation calibration
curves and dose and uncertainty assessment procedures;
— the results of proficiency tests.
Laboratory networks should perform on regular basis:
a) standardization of techniques involved including, for example, formatting of data reporting to
enable pooling of data in a combined response;
b) organization of regular training activities among network staff in support of validation,
standardization and maintenance of expertise, to include periodic inter-laboratory comparisons
with network partners to ensure the consistency of their analytical procedures and dose estimates.
This also can include developing a panel of reference microscope slides that can be used for
evaluating individual scorers when there are staff changes and when other laboratories join the
network;
c) regular exchange in respect of all scientific, technical and administrative questions related to the
network tasks;
7.3 Laboratory network operation
7.3.1 General
This subclause describes the requirements once a lead laboratory has decided to request assistance
from associate laboratories leading to the activation of the network.
ISO 21243:2022(E)
7.3.2 Lead laboratory responsibilities
In an emergency, when the decision to activate the network is taken, the lead laboratory (ideally
the laboratory based in the country where the radiation incident occurs) becomes the nucleus for
communication between the network and other organizations involved in the emergency response.
The lead laboratory informs the associate laboratories of the necessary details of the incident, taking
into consideration required levels of confidentiality and privacy, and together they establish the extent
of cooperation needed. Depending on the situation, the lead laboratory can decide to set up a decision
board involving members of the network. However, in all cases, the lead laboratory and the associate
laboratories should maintain an open dialogue regarding all aspects of the response.
When the network is activated, the following items shall be clearly defined by the lead laboratory/
decision board:
a) the technical details of the response of the network to the emergency in terms of techniques used,
countries/laboratories activated and data interpretation. The lead laboratory maintains records
pertaining to which laboratories are validated and thus can be relied upon to assist, on the basis of
the results of proficiency testing as well as shared information regarding capacity;
b) logistical organization and planning
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