ISO 27368:2008

Analysis of blood for asphyxiant toxicants — Carbon monoxide and hydrogen cyanide

ISO 27368:2008 details analytical methods suitable for analysing the two primary toxic combustion gases, carbon monoxide (CO) and hydrogen cyanide (HCN), in blood samples collected from fire casualties. In blood, CO is measured as carboxyhaemoglobin (COHb) and HCN as cyanide ion (CN-). Although numerous methods are reported in the literature for performing blood COHb and CN- analyses, the analytical methods included herein are based upon their suitability for performing the analysis on ante-mortem and post-mortem blood samples from fire casualties. The analytical principle, analysis time, repeatability, reproducibility, robustness, effectiveness and instruments used are considered for those methods. Some of the methods described in ISO 27368:2008 might not be suitable for analysing putrid or clotted blood. Burned (solid) blood can be analysed after homogenization.

Analyse du sang pour substances toxiques asphyxiantes — Monoxyde de carbone et acide cyanhydrique

General Information

• Status: Published
• Publication Date: 10-Aug-2008
• ICS: 13.220.99 - Other standards related to protection against fire
• Technical Committee: ISO/TC 92/SC 3 - Fire threat to people and environment
• Drafting Committee: ISO/TC 92/SC 3 - Fire threat to people and environment
• Current Stage: 9093 - International Standard confirmed
• Start Date: 24-Oct-2022
• Completion Date: 19-Apr-2025

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 27368
First edition
2008-08-15
Analysis of blood for asphyxiant
toxicants — Carbon monoxide and
hydrogen cyanide
Analyse du sang pour substances toxiques asphyxiantes — Monoxyde
de carbone et acide cyanhydrique

Reference number
©
ISO 2008
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©  ISO 2008
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ii © ISO 2008 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols and abbreviated terms . 5
5 Blood samples . 6
5.1 General. 6
5.2 Sample condition. 6
5.3 Sample collection . 6
5.4 Sample storage . 7
5.5 Sample analysis. 7
6 Materials . 7
7 Common quality analytical elements. 7
7.1 General. 7
7.2 Qualitative, quantitative and confirmatory analyses . 7
7.3 Replicate analyses. 7
7.4 Analytical batch . 8
7.5 Open controls. 8
7.6 Calibrators . 8
8 Measurement of CO in blood as COHb. 8
8.1 COHb by whole-blood oximeters . 8
8.2 COHb by palladium chloride reduction .10
8.3 COHb by visible spectrophotometry (using calibration curve) . 12
8.4 COHb by visible spectrophotometry (with CO saturation). 14
8.5 COHb by visible spectrophotometry (without CO saturation) . 16
8.6 COHb by headspace gas chromatography — Nickel-hydrogen reduction and flame
ionization detection . 19
8.7 COHb by headspace gas chromatography — Thermal conductivity detection. 22
−
9 Measurement of HCN in blood as CN . 23
−
9.1 CN by colourimetric method (p-nitrobenzaldehyde and o-dinitrobenzene). 23
−
9.2 CN by visible spectrophotometry. 25
−
9.3 CN as HCN by headspace gas chromatography — Nitrogen phosphorous detection. 29
−
9.4 CN by headspace gas chromatography — Electron capture detection . 31
−
9.5 CN by spectrophotofluorimetry or high-performance liquid chromatography using a
fluorescence detector. 33
−
9.6 CN by high-performance liquid chromatography–mass spectrometry. 37
Annex A (normative) Analytical report pro forma. 41
Annex B (informative) Additional aspects of analytical methods . 43
Annex C (informative) Interpretation of results. 47
Bibliography . 52

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 27368 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 3, Fire threat to
people and environment.
iv © ISO 2008 – All rights reserved

Introduction
Carbon monoxide (CO) and hydrogen cyanide (HCN) are two of the primary toxic combustion gases present
in fire atmospheres. Upon burning, carbon-containing substances generate CO, whereas nitrogen-containing
substances also produce HCN. Since structures surrounding human beings are composed of polymeric
materials containing carbon and nitrogen elements as their constituents, these materials generate CO and
HCN upon burning and fire victims are exposed to these gases by inhaling smoke. Although ISO 19701
documents methods for the analysis of CO and HCN in fire effluents, the actual toxic insult to exposed
persons can be assessed only by the analysis of the fire casualties' blood for CO as carboxyhaemoglobin
−
(COHb) and HCN as cyanide ion (CN ). These analytical findings are useful for
⎯ estimating life-threatening characteristics of fire atmospheres,
⎯ evaluating the degree of toxicity caused by smoke inhalation in fire victims,
⎯ determining the cause and manner of death of fire victims,
⎯ improving understanding of the direct causes of fire injury and death,
⎯ enhancing understanding of acute and delayed adverse effects of smoke on fire casualties,
⎯ administering immediate treatment for smoke poisoning and monitoring delayed adverse effects of smoke,
⎯ choosing appropriate emergency, long-term and/or follow-up treatments for surviving fire casualties,
⎯ setting priorities for emergency treatment of multiple fire casualties,
⎯ establishing relationships between the concentrations of CO and HCN in a fire atmosphere, blood COHb
−
and CN levels, and the degree of toxicity and performance impairment,
⎯ achieving correlations between concentrations of the two gases in fire atmospheres and of COHb and
−
CN in blood in order to improve tenability models,
⎯ identifying deficiencies with materials, products, assemblies, structures and escape routes, and
⎯ improving forensic toxicology analytical processes and procedures.
Compliance with this International Standard can help ensure a consistent data set for use in a variety of fields
such as
a) fire statistics, which themselves are frequently used to develop regulatory policy,
b) international collaboration on improved design, materials and use of habitable structures, and,
c) ultimately, improvement of international relations and trades.
Such compliance can further assist in developing better and safer fire-safety instruments and structures
(residential and commercial buildings; locomotive passenger vans, automobiles, aerospace vehicles and other
vehicular structures).
Various different methods are currently used for obtaining blood analysis data for these two fire toxicants and
the lack of standardized procedures can result in a wide variation of interpretation. It is, therefore, proposed to
set out best-practice, standardized procedures for blood sample collection, sample storage, sample
processing/preparation, sample treatment and transfer to analytical instrumentation, analytical instrumentation
and techniques, data presentation and reporting, and guidance for data interpretation. The analytical methods
included herein are based upon their suitability for performing an analysis on ante-mortem and post-mortem
blood samples from fire victims and are commonly used in forensic toxicological analytical operations.
This International Standard is structured as follows.
⎯ Clause 1 describes the scope of this International Standard.
⎯ Clause 2 cites the normative references.
⎯ Clause 3 provides terms and their definitions.
⎯ Clause 4 lists symbols and abbreviated terms.
⎯ Clause 5 provides a general description of collecting, storing and analysing blood samples.
⎯ Clause 6 covers the quality of materials used during an analysis.
⎯ Clause 7 summarizes common quality analytical elements.
⎯ Clause 8 describes analytical methods for measuring CO as COHb.
−
⎯ Clause 9 delineates analytical methods for measuring HCN as CN in blood.
⎯ Annex A (normative) lists the information crucial for reporting blood analysis results.
⎯ Annex B (informative) outlines additional aspects of analytical methods.
⎯ Annex C (informative) discusses the interpretation of results, including the interactive effects of CO and
HCN.
⎯ The bibliography includes references cited in this International Standard.

vi © ISO 2008 – All rights reserved

INTERNATIONAL STANDARD ISO 27368:2008(E)

Analysis of blood for asphyxiant toxicants — Carbon monoxide
and hydrogen cyanide
SAFETY PRECAUTIONS — Due consideration shall be given to the fact that both the blood samples
for the analyses of asphyxiant toxicants, carbon monoxide (CO) and hydrogen cyanide (HCN), and
many of the reagents used for their analyses can be biohazardous and/or toxic and can thereby pose
serious health hazards. It is recommended that the collection of blood samples from fire victims be
performed by medical practitioners and in accordance with best practices established by the medical
authorities in the area. Additionally, it is assumed that the procedures described herein are carried out
by suitably qualified professional personnel, adequately trained in the hazards and risks associated
with the handling of biological samples and such analyses and aware of any safety regulations that
can be in effect. Consideration shall also be given to the safe and ecologically acceptable disposal of
all biological samples and chemicals used for analyses. Thi
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