oSIST prEN ISO 25379-1:2026

• Abstract:

  This document specifies requirements and gives recommendations for next generation sequencing (NGS) workflows. This document covers the pre-examination processes, human DNA (somatic and germline) isolation, sequencing library preparation, sequencing, sequence analysis and reporting of the examination of sequences for diagnostic purposes from isolated DNA from, e.g. formalin-fixed and paraffin embedded tissues, fresh frozen tissues, fine needle aspirates (FNA), whole blood, circulating tumour cells (CTCs), exosomes and other extracellular vesicles, circulating cell free DNA from plasma, and DNA from saliva. NOTE 1 Typical applications include, but are not limited to, NGS for oncology, pharmacogenomics and clinical genetics; approaches include panels (e.g. disease panels, exome panels, target gene panels and in silico panels), exome and whole genome sequencing, as well as certain epigenetics and certain single-cell analyses. This document is addressing in vitro diagnostic examinations including laboratory developed tests and is applicable to medical laboratories, molecular pathology laboratories and molecular genetic laboratories, in vitro diagnostic developers and manufacturers, biobanks as well as institutions and organizations performing biomedical research or sequencing services. This document is not applicable for in situ sequencing, DNA-mediated protein sequencing, forensic sequencing, sequencing of pathogens or microorganisms and microbiome analysis. NOTE 2 International, national or regional regulations or requirements or multiples of them can also apply to specific topics covered in this document.

• Status: Not Published
• Public Enquiry End Date: 29-Nov-2026
• ICS: 11.100.10 - In vitro diagnostic test systems
• Technical Committee: VAZ - Healthcare
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 24-Sep-2026
• Due Date: 11-Feb-2027
• Ref Project: prEN ISO 25379-1 - In vitro diagnostic Next Generation Sequencing (NGS) workflows -- Part 1: Part 1: Human DNA examination (ISO/DIS 25379-1:2026)

• Revises: SIST-TS CEN/TS 17981-1:2024 - In vitro diagnostic Next Generation Sequencing (NGS) workflows - Part 1: Human DNA examination
• Effective Date: 19-Feb-2025

oSIST prEN ISO 25379-1:2026 is the Slovenian draft adoption of ISO/DIS 25379-1:2026, published by SIST and developed in ISO/TC 212. It specifies requirements and recommendations for in vitro diagnostic next generation sequencing (NGS) workflows for human DNA examination, from pre-examination through sequencing, sequence analysis and reporting for diagnostic purposes. It is written for medical laboratories, molecular pathology and molecular genetic laboratories, in vitro diagnostic developers and manufacturers, biobanks, and organizations that perform biomedical research or sequencing services.

What does oSIST prEN ISO 25379-1:2026 specify?

oSIST prEN ISO 25379-1:2026 covers NGS workflows for in vitro diagnostics and biomedical research, focused on human DNA, including somatic and germline DNA. It applies to diagnostic examinations from isolated DNA taken from sources such as FFPE tissue, fresh frozen tissue, FNA, whole blood, CTCs, exosomes and other EVs, circulating cell free DNA from plasma, and saliva.

The standard also frames typical use cases such as oncology, pharmacogenomics and clinical genetics. It covers panels, exome sequencing, whole genome sequencing, and some epigenetics and single-cell analyses.

It does not apply to in situ sequencing, DNA-mediated protein sequencing, forensic sequencing, sequencing of pathogens or microorganisms, or microbiome analysis.

The document is organized into Clauses 1 to 10, with Annex A and Annex B.

Annex	What it covers
A	Normative requirements for an in vitro diagnostic NGS workflow for single-cell analyses
B	Informative NGS workflow scheme for the examination of DNA

What are the key requirements of oSIST prEN ISO 25379-1:2026?

oSIST prEN ISO 25379-1:2026 treats the whole NGS workflow as one controlled process. The main practical message is that design, validation, reporting and routine use must all fit the intended use and the specimen type.

• Clause 4.1 links the workflow to a quality system. Medical laboratories are directed to follow ISO 15189 or an equivalent such as ISO/IEC 17020 or ISO/IEC 17025, while IVD manufacturers should follow ISO 13485. In practice, this means the NGS workflow is not only a technical method - it has to sit inside a documented quality management system.

• Clause 4.2 requires defined design inputs. The examination manufacturer shall document scientific validity, customer and stakeholder needs, intended use, and design input specifications. This matters because the reportable claims, specimen types, controls and performance targets all depend on those decisions.

• Clause 4.3 focuses development on risk and optimization. The document points to risk assessment, Design of Experiments (DoE), and guard band studies for critical input parameters. In practice, the manufacturer should identify what most affects the result, test it systematically, and define the tolerance limits before routine use.

• Clause 4.4 requires verification and validation of the whole workflow. The manufacturer shall document verification and validation plans and confirm the intended use on the basis of the planned workflow. If products are supplied for use in the workflow, the performance requirements must still be demonstrated. This is what turns a promising assay design into one that is ready for use.

• Clause 4.5 requires technical performance characteristics to be established. The document highlights analytical accuracy, analytical sensitivity or positive percentage agreement (PPA) when no reference method is available, analytical specificity or negative percentage agreement (NPA) when no reference method is available, precision, limits of detection (LOD) and where applicable LODP, reportable range, reference range, interferences, sequence base quality, clinically relevant performance characteristics, and the performance of each reported variant class such as SNVs, indels, CNAs and SVs. For the user, this is the evidence base for deciding what the assay can and cannot reliably report.

• Clauses 5 and 6 define the technical workflow. The standard covers specimen collection, transport, storage, DNA isolation, DNA quality and quantity evaluation, sequencing library preparation, equipment requirements, sequencing quality control, data analysis, and QC. It explicitly includes material-specific routes such as FFPE, fresh frozen tissue, FNA, whole blood, CTCs, EVs, plasma ccfDNA, saliva and other body fluids. In practice, the lab must choose and document the right path for the specimen actually received.

• Clauses 7 to 10 control reporting, implementation and ongoing QA. The report has to be accurate, clear and unambiguous, with defined attributes and content, and with reporting that supports clinical interpretation. Clause 9 prefers qualitative wording such as “Detected” or “Not detected” rather than “Positive” or “Negative”. Clause 10 requires ongoing monitoring, internal and external controls, documentation of performance data, and participation in proficiency testing where appropriate.

Annex A adds single-cell specific requirements, including the need to address cell capture, amplification bias, sequencing depth, data analysis and the special challenges of CTCs and single cells from tissue. Annex B gives the overall workflow view for DNA examination.

What terms does oSIST prEN ISO 25379-1:2026 define?

• Next generation sequencing (NGS) - advanced sequencing technologies developed after DNA sequencing by the dideoxy termination method.
• Massively parallel sequencing (MPS) - nucleic acid sequencing techniques that detect millions or billions of sequences in parallel.
• Sequencing library - DNA, cDNA or RNA prepared for NGS within a specific size range and carrying adaptors for the sequencing platform.
• Pre-examination processes - the steps from request and specimen collection through transport, storage and isolation of analytes.
• Circulating cell free DNA (ccfDNA) - extracellular human DNA present in blood and plasma, including DNA in vesicles such as exosomes.
• Laboratory developed examination - an examination made or modified and used by a health institution or medical laboratory only in its own facility for specific needs.
• Bioinformatics pipeline - the suite of bioinformatics tools that process NGS data.

Who uses oSIST prEN ISO 25379-1:2026?

oSIST prEN ISO 25379-1:2026 is used by medical laboratories, molecular pathology laboratories and molecular genetic laboratories that design, validate and run NGS assays. It is also relevant to IVD developers and manufacturers, biobanks, and institutions or organizations providing biomedical research or sequencing services.

In practice, these users apply it to specimen handling, DNA isolation, library preparation, sequencing, data analysis, reporting, QC, validation, implementation into routine work, and ongoing performance monitoring.

Which standards are used with oSIST prEN ISO 25379-1:2026?

• ISO 7552-2 - pre-examination for CTCs in venous whole blood, for isolated DNA.
• ISO 18702 - pre-examination for exosomes and other extracellular vesicles in venous whole blood.
• ISO 18704 - pre-examination for urine and other body fluids, for isolated cell-free DNA.
• ISO 4307 - pre-examination for saliva, for isolated human DNA.
• ISO 20166-3 - pre-examination for FFPE tissue, isolated DNA.
• ISO 20184-3 - pre-examination for frozen tissue, isolated DNA.
• ISO 20186-2 - pre-examination for venous whole blood, isolated genomic DNA.
• ISO 20186-3 - pre-examination for venous whole blood, isolated circulating cell free DNA from plasma.
• ISO 20397-1 - library preparation and nucleic acid preparation for massively parallel sequencing.
• ISO 20397-2 - quality evaluation of sequencing data and QC requirements for sequencing data analysis.
• ISO 13485 - quality management system requirements for IVD manufacturers.
• ISO 15189:2022 - laboratory quality and competence requirements used throughout the workflow.
• ISO/IEC 17020:2012 and ISO/IEC 17025:2017 - alternative competence and quality frameworks named for relevant laboratory functions.

The document also points to ISO 15190 for laboratory safety, ISO 8601-1 for date and time formatting in reports, and ISO 5649:2024 for concepts and specifications for laboratory-developed tests.

What does the oSIST prEN ISO 25379-1:2026 document contain?

The document contains the workflow structure for human DNA NGS examinations, from scope and terms to general requirements, technical development, reporting and quality assurance. It also includes specimen-specific pre-examination topics, library preparation steps, sequencing quality control, bioinformatics and reporting rules, and the routine-practice requirements for implementation.

It includes an informative workflow scheme in Annex B and a normative single-cell workflow in Annex A. The body of the standard also refers to tables for pre-examination documents and for performance characteristics, and to report content that includes result interpretation, limitations, report identification and review authorization.

SLOVENSKI STANDARD
01-november-2026
In vitro diagnostični delovni postopki z uporabo sekvenciranja naslednje
generacije (NGS) - 1. del: Preiskava človeškega DNK (ISO/DIS 25379-1:2026)
In vitro diagnostic Next Generation Sequencing (NGS) workflows - Part 1: Human DNA
examination (ISO/DIS 25379-1:2026)
Next-Generation-Sequencing(NGS)-Arbeitsabläufe für die In-vitro-Diagnostik - Teil 1:
Untersuchung von menschlicher DNA (ISO/DIS 25379-1:2026)
Flux de travaux pour le diagnostic in vitro par séquençage de nouvelle génération (NGS)
- Partie 1: Examen de l'ADN humain (ISO/DIS 25379-1:2026)
Ta slovenski standard je istoveten z: prEN ISO 25379-1
ICS:
11.100.10 Diagnostični preskusni In vitro diagnostic test
sistemi in vitro systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 25379-1
ISO/TC 212
In vitro diagnostic Next Generation
Secretariat: ANSI
Sequencing (NGS) workflows —
Voting begins on:
Part 1: 2026-09-16
Human DNA examination
Voting terminates on:
2026-12-09
Flux de travaux pour le diagnostic in vitro par séquençage de
nouvelle génération (NGS) —
Partie 1: Examen de l'ADN humain
ICS: 11.100.10
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 has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
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NOTIFICATION OF ANY RELEVANT PATENT
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PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 25379-1:2026(en)
DRAFT
ISO/DIS 25379-1:2026(en)
International
Standard
ISO/DIS 25379-1
ISO/TC 212
In vitro diagnostic Next Generation
Secretariat: ANSI
Sequencing (NGS) workflows —
Voting begins on:
Part 1:
2026-09-16
Human DNA examination
Voting terminates on:
2026-12-09
Flux de travaux pour le diagnostic in vitro par séquençage de
nouvelle génération (NGS) —
Partie 1: Examen de l'ADN humain
ICS: 11.100.10
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 has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
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
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Published in Switzerland Reference number
ISO/DIS 25379-1:2026(en)
ii
ISO/DIS 25379-1:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 14
4.1 General .14
4.2 Examination design. 15
4.3 Examination development .19
4.4 Examination performance verification and validation . 20
4.5 Technical examination performance characteristics . 25
5 Pre-examination processes for examination development .26
5.1 General . 26
5.2 Human DNA isolation .27
5.2.1 General .27
5.2.2 Isolation from formalin fixed and paraffin embedded (FFPE) tissue .27
5.2.3 Isolation from fresh frozen tissue .27
5.2.4 Isolation from fine needle aspirates (FNA) .27
5.2.5 Isolation from whole blood .27
5.2.6 Isolation of circulating cell free DNA from plasma . 28
5.2.7 Isolation of DNA from saliva . 28
5.2.8 Isolation of cfDNA from other body fluids . 28
5.3 DNA sample quality and quantity evaluation . 28
6 Examination processes for examination development .29
6.1 Sequencing library preparation for examination development . 29
6.1.1 General . 29
6.1.2 Sequencing library preparation steps . 30
6.1.3 Panels, exomes and whole genome sequencing .32
6.2 NGS equipment requirements and recommendations for examination development . 34
6.2.1 General . 34
6.2.2 Techniques . 34
6.2.3 Sequencing quality control . 35
6.3 Data analysis requirements for examination development . 36
6.4 Quality control (QC) requirements for examination development .37
7 Requirements for the development of the examination reporting tool .37
7.1 General .37
7.2 Report attributes . 38
7.3 Report content . 38
8 Implementation of the in vitro diagnostic NGS workflow into routine practice .39
9 Reporting and interpretation of results .40
10 Quality assurance procedures . 41
10.1 General .41
10.2 Performance monitoring, optimization of the examination and interlaboratory
comparison .41
Annex A (normative) in vitro diagnostic NGS workflow for single-cell analyses .42
Annex B (informative) NGS workflow scheme for the examination of DNA .49
Bibliography .51

iii
ISO/DIS 25379-1:2026(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 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).
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 212, Medical laboratories and in vitro diagnostic
systems, in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 140, In vitro diagnostic medical devices, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 25379 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.

iv
ISO/DIS 25379-1:2026(en)
Introduction
Molecular in vitro diagnostics has enabled significant progress in medicine. Further progress is expected by
new technologies analysing profiles of nucleic acids, proteins, and metabolites in human tissues and body
fluids. Next Generation Sequencing (NGS) takes a prominent place in the series of molecular techniques used
for diagnostics. It facilitates sequence analysis of nucleic acids that can result in precise information for
diagnosis and progression of diseases.
The NGS technique, however, has a very complex workflow that contains many steps. The target nucleic acids
can originate from different sources (e.g. tissues, blood, and body fluids). The profiles of the isolated DNA or
methylated DNA can change during specimen collection, transport, storage and processing (e.g. formalin
fixation), making the outcome from diagnostics or research unreliable or even impossible because the
subsequent analytical assay will not determine the situation in the patient, but an artificial profile generated
during the pre-examination process. The available material can be small, the cells in a tissue can be dispersed
heterogeneously (e.g. ratio of tumour to normal), the target nucleic acids can be circulating in blood or body
fluids free of cells or in circulating cells (e.g. circulating tumour cells (CTCs)). For a successful and reliable
sequencing result, a suitable strategy needs to be chosen for every case depending on the available material
and disease conditions. Therefore, the NGS workflow can differ from case to case, and the NGS workflow
steps need to be carefully considered and chosen to get a sound and reliable result to determine the best
available treatment for the patient. In addition, sequencing platforms can differ in their technique (e.g.
detection of a change in a current or fluorescence) and approach (e.g. panels, short-read sequencing, long-
read sequencing) for sequence assessment. The bioinformatics analysis can differ in approach and ability
to detect non-conformities and unreliable sequencing results. To enable such capabilities, NGS metadata
needs to be collected during all workflow steps from the patient to the reporting. In addition, controls and
added controls need to be analysed properly. In this way, non-conformities or detected unreliabilities can
be reported to the patient and the treating physician. The reporting of diagnostic NGS results can differ in
clarity and depth, which can lead to different interpretations.
Standardization of the entire NGS workflow from specimen collection to the reporting of the results to the
patient and the treating physician is needed for the development of reliable NGS examinations.
This document draws upon previous work to standardize the steps for NGS examinations from tissues, blood
and body fluids in what is referred to as the pre-examination phase (sample collection), the examination
phase (library preparation, sequencing), and the post-examination phase (analysis and reporting).
In this document, the following verbal forms are used:
— “shall” indicates a requirement;
— “should” indicates a recommendation;
— “may” indicates a permission;
— “can” indicates a possibility or a capability.

v
DRAFT International Standard ISO/DIS 25379-1:2026(en)
In vitro diagnostic Next Generation Sequencing (NGS)
workflows —
Part 1:
Human DNA examination
1 Scope
This document specifies requirements and gives recommendations for next generation sequencing (NGS)
workflows for in vitro diagnostics and biomedical research. This document covers the pre-examination
processes including human DNA (somatic and germline) isolation, sequencing library preparation,
sequencing, sequence analysis and reporting of the examined sequences for diagnostic purposes from
isolated DNA from, e.g. formalin-fixed and paraffin embedded tissues, fresh frozen tissues, fine needle
aspirates (FNA), whole blood, circulating tumour cells (CTCs), exosomes and other extracellular vesicles,
circulating cell free DNA from plasma, and DNA from saliva.
NOTE 1 Typical applications include, but are not limited to, NGS for oncology, pharmacogenomics and clinical
genetics; approaches include panels (e.g. disease panels, exome panels, target gene panels and in silico panels), exome
and whole genome sequencing, as well as certain epigenetic and certain single-cell analyses.
This document addresses in vitro diagnostic examinations including laboratory developed examinations and
is applicable to medical laboratories, molecular pathology laboratories and molecular genetic laboratories,
in vitro diagnostic developers and manufacturers, biobanks and institutions and organizations performing
biomedical research or sequencing services.
This document is not applicable for in situ sequencing, DNA-mediated protein sequencing, forensic
sequencing, sequencing of pathogens or microorganisms and microbiome analysis.
NOTE 2 International, national or regional regulations or requirements or multiples of them can also apply to
specific topics covered in this document.
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 7552-2, Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for
circulating tumor cells (CTCs) in venous whole blood — Part 2: Isolated DNA
ISO 18702, Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for
exosomes and other extracellular vesicles in venous whole blood — DNA, RNA and proteins
ISO 18704, Molecular in vitro diagnostic examinations — Requirements and recommendations for pre-
examination processes for urine and other body fluids — Isolated cell-free DNA
ISO 4307, Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for saliva
— Isolated human DNA
ISO 13485, Medical devices — Quality management systems — Requirements for regulatory purposes
ISO 15189:2022, Medical laboratories — Requirements for quality and competence

ISO/DIS 25379-1:2026(en)
ISO/IEC 17020:2012, Conformity assessment — Requirements for the operation of various types of bodies
performing inspection
ISO/IEC 17025:2017, General requirements for the competence of testing and calibration laboratories
ISO 20166-3, Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for
formalin-fixed and paraffin-embedded (FFPE) tissue — Part 3: Isolated DNA
ISO 20184-3, Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for
frozen tissue — Part 3: Isolated DNA
ISO 20186-2, Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for
venous whole blood — Part 2: Isolated genomic DNA
ISO 20186-3, Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for
venous whole blood — Part 3: Isolated circulating cell free DNA from plasma
ISO 20397-1:2022, Biotechnology — Massively parallel sequencing — Part 1: Nucleic acid and library preparation
ISO 20397-2, Biotechnology — Massively parallel sequencing — Part 2: Quality evaluation of sequencing data
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15189 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
aliquot
portion of a larger amount of homogenous material, assumed to be taken with negligible sampling error
Note 1 to entry: The term is usually applied to fluids. Tissues are heterogeneous and therefore cannot be aliquoted.
[1][2][3]
Note 2 to entry: The definition is derived from .
[SOURCE: ISO 20184-3:2021, 3.1, modified ─ Note 2 to entry was added.]
3.2
amplicon
specific DNA fragment produced by a DNA-amplification technology, such as the polymerase chain reaction
(PCR)
[SOURCE: ISO 13495:2013, 3.3.1]
3.3
analyte
component represented in the name of a measurable quantity
Note 1 to entry: The term “analyte”, or the name of a substance or compound, is not to be confused with the term
“measurand”, because analytes are not quantities.
EXAMPLE Amount of substance of glucose in plasma is a measurand (3.39), while glucose is the analyte.
[SOURCE: ISO 17511:2021, 3.1, modified — Note 1 and example were added]

ISO/DIS 25379-1:2026(en)
3.4
analytical accuracy
closeness of the agreement between the result of an examination (3.23) and a true property value
Note 1 to entry: For NGS-based examinations, accuracy represents the degree of concordance (or agreement) of results
between a sequence obtained from the examination and the same sequence determined by a valid comparator method,
or between a reference sample run on an NGS-based examination and the high confidence sequence of the reference.
[SOURCE: ISO/IEC Guide 99:2007, 2.13, modified – Original notes were deleted, Note 1 to entry was added;
"analytical accuracy" replaces all old terms, "a measured quantity value" was replaced by "the result of an
examination" and "quantity value of a measurand" was replaced by "property value".]
3.5
analytical sensitivity
sensitivity of a measurement procedure
quotient of the change in a measurement (3.40) indication and the corresponding change in a value of a
quantity being measured
Note 1 to entry: The sensitivity of a measurement procedure (3.41) can depend on the value of the quantity being
measured.
Note 2 to entry: The change considered in the value of the quantity being measured only becomes useful when large
compared with the resolution.
Note 3 to entry: The analytical sensitivity of a measuring system is the slope of the calibration curve.
Note 4 to entry: Analytical sensitivity is often confused with positive percentage agreement (PPA), because similar
calculations are used for both the analytical sensitivity and the PPA. However, the term PPA instead of analytical
sensitivity is only used, if a reference method is not available or not used. The PPA represents merely an estimation of
the analytical sensitivity. PPA is applicable only to measurements of quantities that have the nature of a count.
[SOURCE: ISO/IEC Guide 99:2007, 4.12, modified — terms changed from "sensitivity of a measuring system
/sensitivity" changed to "analytical sensitivity/sensitivity of a measurement procedure"; "an indication of a
measuring system" replaced by "a measurement indication", "measuring system" replaced by "measurement
procedure" in Note 1; new Note 3 and Note 4 were added.]
3.6
analytical specificity
selectivity of a measurement procedure
capability of a measuring system, using a specified measurement procedure (3.41), to provide measurement
(3.40) results for one or more measurands (3.39) which do not depend on each other nor on any other
quantity in the system undergoing measurement
Note 1 to entry: Lack of analytical specificity is called analytical interference (see ISO 18113-1:2022, 3.2.2).
Note 2 to entry: Specificity of a measurement procedure (3.41) should not be confused with diagnostic specificity (3.14)
(see ISO 18113-1:2022, 3.2.18).
Note 3 to entry: ISO/IEC Guide 99:2007 uses the term selectivity for this concept instead of specificity.
Note 4 to entry: Adapted from ISO/IEC Guide 99:2007, 4.13.
Note 5 to entry: Selectivity as used in metrology is a concept close to specificity as it is sometimes used in chemistry.
“Specificity” of measurements has some risk of ambiguity with “clinical/diagnostic specificity”.
Note 6 to entry: Analytical specificity is often confused with negative percentage agreement (NPA), because the same
calculations are used for both the analytical specificity and the NPA. However, the term NPA instead of analytical
specificity is only used, if a reference method (3.54) is not available or is not used. The NPA represents merely an
estimation of the analytical specificity.
[SOURCE: ISO 18113-1:2022, 3.2.5, modified — Note 2 was deleted and Note 5 and 67 were added.]

ISO/DIS 25379-1:2026(en)
3.7
bioinformatics pipeline
suite of different bioinformatics tools that process the next generation sequencing (3.43) data
3.8
biomarker
molecular marker
detectable and/or quantifiable molecule or group of molecules used to indicate a biological condition, state,
identity or characteristic or an organism
[SOURCE: ISO 16577:2022, 3.4.28]
3.9
circulating cell free DNA
ccfDNA
extracellular human DNA present in blood and plasma
Note 1 to entry: ccfDNA includes DNA present in vesicles such as exosomes.
[SOURCE: EN ISO 20186-3:2019, 3.5]
3.10
cell free DNA
cfDNA
extracellular human DNA present in body liquids such as urine and plasma
Note 1 to entry: cfDNA can include DNA present in vesicles such as exosomes.
[SOURCE: ISO/DIS 18704, 3.8]
3.11
clinical accuracy
diagnostic accuracy
extent of agreement between the outcome of the examination (3.23) and the target clinical condition
3.12
clinical performance
ability of an examination (3.23) to yield results that are correlated with a particular clinical condition,
physiological or pathological state in accordance with the target population and intended use(r)
Note 1 to entry: Although sometimes referred to as diagnostic performance or clinical validity (3.16); clinical
performance is the harmonized term endorsed by the Global Harmonization Task Force (GHTF) and its successor, the
International Medical Devices Regulators Forum (IMDRF).
Note 2 to entry: Evaluation of clinical performance often relies on the outcome of other types of clinical examinations
(3.23) to define “true positive or true negative” results.
3.13
clinical sensitivity
diagnostic sensitivity
ability of an in vitro diagnostic examination (3.23) procedure to have positive results associated with a
particular disease or condition
Note 1 to entry: Also defined as percent positivity in samples where the target marker is known to be present.
Note 2 to entry: Diagnostic sensitivity is expressed as a percentage (number fraction multiplied by 100), calculated as
100 × the number of true positive values (TP) divided by the sum of the number of true positive values (TP) plus the
number of false negative values (FP), or 100 × TP/(TP + FN). This calculation is based on a study design where only
one sample is taken from each subject.
Note 3 to entry: The target condition is defined by criteria independent of the examination procedure under
consideration.
ISO/DIS 25379-1:2026(en)
Note 4 to entry: Clinical sensitivity is often confused with positive percentage agreement (PPA), because the same
calculations are used for both the clinical sensitivity and the PPA. However, the term PPA instead of clinical sensitivity
is only used, if a reference method is not available or is not used. The PPA represents merely an estimation of the
clinical sensitivity.
[SOURCE: ISO 18113-1:2022, 3.2.17, modified — The term "clinical sensitivity" was added; second sentence
in Note 1 was deleted; Note 4 was added.]
3.14
clinical specificity
diagnostic specificity
ability of an in vitro diagnostic examination (3.23) procedure to have negative results associated with an
absence of particular disease or condition
Note 1 to entry: Also defined as percent negativity in samples where the target marker is known to be absent. For
information regarding description of the diagnostic performance characteristics of an IVD medical device, see
Reference [4].
Note 2 to entry: Clinical specificity is expressed as a percentage (number fraction multiplied by 100), calculated as
100 × the number of true negative values (TN) divided by the sum of the number of true negative plus the number of
false positive values (FP), or 100 × TN/(TN + FP). This calculation is based on a study design where only one sample is
taken from each subject.
Note 3 to entry: The target condition is defined by criteria independent of the examination (3.23) procedure under
consideration.
Note 4 to entry: Clinical specificity is often confused with negative percentage agreement (NPA), because the same
calculations are used for both the clinical specificity and the NPA. However, the term NPA instead of clinical specificity
is only used, if a reference method (3.54) is not available or is not used. The NPA represents merely an estimation of the
clinical specificity.
[SOURCE: ISO 18113-1:2022, 3.2.18, modified — The term "clinical specificity" was added; Note 4 was
added.]
3.15
clinical utility
ability of a screening or diagnostic examination (3.23) to prevent or ameliorate adverse health outcomes
such as mortality, morbidity, or disability through the adoption of efficacious treatments conditioned on
examination results
[5][6]
Note 1 to entry: Clinical utility can be part of scientific validity and clinical performance (3.12) .
[6]
[SOURCE: ]
3.16
clinical validity
predictive value of an examination (3.23) for a given clinical outcome
Note 1 to entry: Clinical validity is primarily determined by the clinical sensitivity (3.13) and clinical specificity (3.14)
with which an examination identifies individuals with a defined clinical condition within a given population. The
clinical validity (3.16) of a genetic examination is the likelihood that, e.g. cancer will develop in someone with a positive
examination result.
3.17
closed system
non-modifiable system (by the user) provided by the vendor including all necessary components for the
examination (3.23)
Note 1 to entry: Necessary components are hardware, software, procedures and reagents.

ISO/DIS 25379-1:2026(en)
3.18
Design of Experiments
DoE
structured, statistical approach for planning sequencing runs and experimental conditions in order
to systematically evaluate the effects of key variables (e.g. library preparation methods, input nucleic acid
quantity, sequencing depth, and indexing strategies) on sequencing quality, coverage, and downstream data
interpretation
3.19
diagnosis
identification of a disease from its signs and symptoms, where the diagnostic process can involve
examinations (3.23) and tests for classification of an individual's condition into separate and distinct
categories or subclasses that allow medical decisions about treatment and prognosis to be made
3.20
deoxyribonucleic acid
DNA
polymer of deoxyribonucleotides occurring in a double-stranded (dsDNA) or single-stranded (ssDNA) form
3.21
DNA sequencing
determining the order of nucleotide bases (e.g. adenine, guanine, cytosine and thymine) in a molecule of DNA
(3.20)
Note 1 to entry: Sequence is generally described from the 5’ end.
[SOURCE: ISO 17822:2020, 3.19, modified — Added e.g.]
3.22
epigenetics
study of changes of genome usage without alterations in the underlying DNA sequence
[7]
[SOURCE: ]
3.23
examination
analytical test
set of operations having the objective of determining the numerical value or characteristics of a property
Note 1 to entry: An examination can be the total of a number of activities, observations or measurements required to
determine a value or characteristic.
Note 2 to entry: Laboratory examinations that determine a numerical value of a property are called "quantitative
examinations"; those that determine the characteristics of a property are called "qualitative examinations".
Note 3 to entry: Laboratory examinations are also called "assays" or "tests".
Note 4 to entry: A “measurement procedure” or “measurement system” becomes an “examination” (also in complex
terms like “examination procedure”), where nominal properties (e.g. DNA bases like G, A, T, C, or a set of terms for the
types of leukocytes found in human blood) or ordinal quantities (e.g. a 5-value scale (0, 1, 2, 3, 4) for dip-stick reading
(assessed using 1 = not elevated, 2 = doubtfully elevated, 3 = slightly elevated, 4 = elevated, 5 = strongly elevated)) are
the results of a “detection” instead of a “measurement” (derived from ISO/DIS 15193).
[SOURCE: ISO 15189:2022, 3.8, modified —A new note 4 to entry was added. “analytical test” has been added
as an alternative term.]
3.24
examination manufacturer
analytical test manufacturer
entity that manufactures and/or produces measurement or detection systems, instruments, and reagents
for a specific examination (3.23)

ISO/DIS 25379-1:2026(en)
3.25
examination performance
analytical test performance
analytical performance
ability of an examination (3.23) procedure to measure or detect a particular analyte (3.3)
Note 1 to entry: Analytical performance is determined from analytical performance studies used to assess the ability
of an in vitro diagnostic examination procedure to measure or detect a particular analyte.
Note 2 to entry: Analytical performance includes such characteristics as analytical sensitivity, detection limit,
analytical specificity (interference and cross-reactivity), trueness, precision and linearity.
[SOURCE: ISO 20186-3:2019, 3.11]
3.26
extracellular vesicle
EV
particle naturally released from the cell that is delimited by a lipid bilayer and cannot replicate, i.e. does not
contain a functional nucleus
EXAMPLE Exosomes, endosomes, oncosomes, apoptotic bodies.
[8]
[SOURCE: ]
3.27
fine needle aspirate
FNA
specimen (3.67) withdrawn by a non-operative procedure that uses a thin, hollow-bore needle
[49]
[SOURCE: CEN/TS 17688-1:2021, 3.18 ]
3.28
formalin
saturated aqueous formaldehyde solution which at 100 % contains 37 % formaldehyde by mass
(corresponding to 40 % by volume)
[SOURCE: ISO 20166-1:2018, 3.11]
3.29
guard band
interval between a tolerance limit and a corresponding acceptance limit
Note 1 to entry: The guard band includes the limits.
[SOURCE: ISO/IEC Guide 98-4:2012, 3.3.11]
3.30
in vitro diagnostic NGS workflow
all activities required to generate the NGS examination result including the pre-examination processes (3.50),
examination (3.23) and post-examination processes (3.49)
3.31
intended use
intended purpose
objective regarding the application of a product, process or service as reflected in the specifications,
instructions and information provided by the examination manufacturer (3.24)
Note 1 to entry: Intended use statements for IVD labelling can include two components: a description of the
functionality of the IVD medical device (e.g. an immunochemical measurement procedure for the detection of analyte
(3.1.4) “x” in serum or plasma), and a statement of the intended medical use of the examination results.
Note 2 to entry: The intended use can include the indications for use.

ISO/DIS 25379-1:2026(en)
Note 3 to entry: The intended purpose indicates the object to be detected/measured, the examination’s function
(screening, monitoring, diagnosis, prognosis, companion diagnostic), if the examination is automated, specific
information to be provided as a component of the device (to determine physiological/pathological state, clinical
condition or predisposition, prediction to treatment response/reaction or monitoring of a therapy or non-proprietary
name of the medicinal product for companion test; safety to recipients), if the examination results are qualitative or
quantitative, the type of specimen required, and the intended population.
Note 4 to entry: The intended purpose directly drives the level of the performance evaluation, the examination
methodology, the hardware and software, the examination limitations, positive controls, risk to health (e.g. diagnostic
use or screening; consequences of false negatives (FN) or false positives (FP)), the number of samples, and the types
of samples.
[SOURCE: ISO 18113-1:2022(en), 3.1.37, modified ― Eliminated circularity and repetition in the definition;
two notes added; “the IVD manufacturer” is replaced with “examination manufacturer”; “supplied” is
replaced with “provided”.]
3.32
intermediate precision
intermediate measurement precision
measurement precision under a set of intermediate precision conditions of measurement (3.33)
Note 1 to entry: Relevant statistical terms are given in ISO 5725-3:1994.
[SOURCE: ISO/IEC Guide 99:2007, 2.23]
3.33
intermediate precision condition of measurement
intermediate precision condition
condition of measurement (3.40), out of a set of conditions that includes the same measurement procedure
(3.41), same location, and replicate measurements on the same or similar objects over an extended period of
time, but can include other conditions involving changes
Note 1 to entry: The changes can include new calibrations, calibrators, operators, and measuring systems.
Note 2 to entry: A specification for the conditions should contain the conditions changed and unchanged, to the extent
practical.
Note 3 to entry: In chemistry, the term “inter-serial precision condition of measurement” is sometimes used to
designate this concept.
[SOURCE: ISO/IEC Guide 99:2007, 2.22, modified – "may" replaced by "can"]
3.34
laboratory developed examination
in-house examination
laboratory developed test
examination (3.23) manufactured or modified and used by health institutions or medical laboratories
intended to be used only in their facility, to fulfil specific needs of target patient groups which cannot be met
by an equivalent IVD examination available on the market at the appropriate level of performance
3.35
limit of detection
detection limit
LOD
measured quantity value, obtained by a given measurement procedure, for which the probability of falsely
claiming the absence of a component in a material is β, given a probability α of falsely claiming its presence
Note 1 to entry: IUPAC recommends default values for α and β equal to 0,05.
Note 2 to entry: The term “sensitivity” is discouraged for this concept.Note 3 to entry: Where the target sequence is
a mixture of detectable and non-detectable sequences, the parameter LODP (3.36) (ISO 16578), which indicates the
lower limit of detection for the platform, should be considered for use instead of LOD.

ISO/DIS 25379-1:2026(en)
[SOURCE: ISO/IEC Guide 99:2007, 4.18, modified — Note 2 was deleted; Note 3 was added.]
3.36
limit of detection for platforms
platform limit of detection
LODP
lowest relative quantity of the external measurement standard or reference material (3.53) for which a
positive identification can be achieved with reasonable or previously determined confidence or both in a
defined matrix using a specific analytical method
Note 1 to entry: In qualitative testing, an estimate of the LOD (3.35) is measured at the chosen probability of detection
(POD).
[SOURCE: ISO 16578:2022(en), 3.1]
3.37
long-read sequencing
subset of massively parallel sequencing (MPS) (3.38) methods capable of measuring nucleic acid sequences of
≥2 kb, that can directly detect DNA bases, RNA bases and nucleic base modifications
Note 1 to entry: Long-read sequencing can be achieved by two approaches at the moment (enzymatic processing or
direct reading).
3.38
massively parallel sequencing
MPS
nucleic acid sequencing techniques that detect millions or billions of sequences from individual input nucleic
acid molecules in parallel
Note 1 to entry: For DNA sequencing, alleles are analysed separately. Combining allele sequences is required to
determine a genotype of a donor/patient at any tested position of the genome. For RNA sequencing, locus-specific
sequences from coding and non-coding RNAs are analysed by counting and/or by determining exon coverage or exon
usage to determine splicing.
Note 2 to entry: Massively parallel sequencing technol
...