Laboratory Perspective:

The challenge of standardisation

in the face of the revolution in

biotechnology and data

processing

Steven Edwards

Consultant Editor, OIE Manual of Diagnostic Tests and Vaccines for

Terrestrial Animals

Definition of a Standard

Oxford English Dictionary has 12 distinct

definitions. The most relevant today are:

A document specifying nationally or

internationally agreed properties for

manufactured goods etc.

“Written standard or procedure”

An object or quality or measure serving as a

basis or example or principle to which others

conform or by which the accuracy or quality of

others is judged

“Standard Reference Material”

OIE Written Standards

The principal written standards

Terrestrial Animal Health Code

Standards for international movements, disease

status and surveillance

Manual of Diagnostic Tests and Vaccines for

Terrestrial Animals

Standards for laboratories, laboratory tests and

reagents, and vaccine manufacture

Aquatic Animal Health Code

Manual of Diagnostic Tests for Aquatic Animals

OIE Quality Standard and Guidelines for

Veterinary Laboratories

The OIE Terrestrial Manual

First edition (1989-91) Loose leaf

Based on expert opinion (chapter authors)

Consensus approval by OIE Member Countries

Subsequent bound editions (every 4 years) Seventh edition 2012

Progressive development to broaden scope and increase rigour

Incorporation of new technologies

But only when the methods have been validated

Recognition

Widely used as a laboratory reference work

WTO sanitary & phytosanitary agreement

From the SPS Agreement

For animal health and zoonoses:

the standards, guidelines and recommendations developed under

the auspices of the OIE

The Validation Framework

Updated text in Manual

adopted 2013

Research provides

proof of principle

Supported by publication

Cannot be considered a

standard method at this

stage

Validation pathway

Fitness for purpose

Established as a

standard

Continual monitoring of

assay in use

Standard reference materials for diagnostic tests

1. Reference strains of pathogens

Should be representative of organisms circulating in the field

Maintained by Reference Laboratories in controlled repositories

Defined characteristics, including passage levels

Used to standardise diagnostic tests, or as standards for vaccines (eg specified in OIE Manual)

Complex for pathogens with multiple circulating types

Continual monitoring for changes in circulating field organisms

2. Serology – the hierarchical approach

Primary Standards Small quantities, use sparingly

Extensively evaluated in multiple laboratories

Defined activity level in a standard test protocol

Designated at international level (eg OIE)

Supplied to National Laboratories

Secondary Standards Prepared by National Laboratory

Calibrated against primary standards

Supplied to diagnostic laboratories in that country

Working standards (tertiary) Used by diagnostic laboratories as working controls

Standard reference materials for

diagnostic tests

FMD

SVD

Rinderpest

PPR

CBPP

Bluetongue

African horse sickness

Classical swine fever

Aujeszky’s disease

Rabies

Brucellosis

EBL

IBR/IPV

EIA

Equine influenza

EVA

Obtained from OIE Reference Laboratories

(see OIE website for details)

Currently available OIE-approved

International Standard Sera

(primary standards)

Important message

For many important diseases we still have

no OIE-designated primary reference

materials, even for serology

There are no OIE-designated primary

reference materials for molecular tests

Standard reference materials for

diagnostic tests

3. Molecular diagnostic methods

Written standards (OIE Manuals) can specify eg primer

sequences for PCR and related assays

Do we need physical standard reference materials?

Parallels with human medicine

Results need to be comparable across time and methods, either by

producing the same value across methods and test versions or by

using reliable and stable conversions. Universally available

standards and reference materials specific to quantitative molecular

technologies are critical to this process but are few in number.

One of the most important considerations in the development of

effective standards and reference materials is that the material be

commutable, ie, behave as closely as possible to the test samples in

the full range of measurement procedures expected to make use of

the material.

[Madej et al., 2010, Journal of Molecular Diagnostics 12: 133-143]

Considerations for nucleic acid

standards Target sequence, length of target sequence

Multiple or single genotypes

Method of preparation of standard Extraction, recombinant, synthetic

Activity level Should give comparable results to real samples

Matrix Should give comparable results to real samples

Should work with all the available technologies

Stability

Consistency

Evaluation and recognition

Availability (cost, shipment issues)

Based on a

WHO

consultation

meeting

An example from avian influenza:

Standard reference materials for

diagnostic tests

4. Mobile and hand-held methods

In effect a subset of traditional technologies

Immunoassay (detection of antigen or antibody)

Nucleic acid detection

Ease of use in the field is critical

Kit formulations – use of controls

Standardisation needs to be incorporated at

the development stage by manufacturer

Ongoing QC vital to ensure consistency and

accuracy

High throughput sequencing,

bioinformatics and computational

genomics (HTS-BCG)

A big challenge for standardisation

OIE ad hoc group identified opportunities and

challenges from this technology

The approach of agreed written standards still

applies

Technical standards for the OIE Manuals

Standard approaches for data processing

Consideration required on how to apply validation

principles to this technology

Criteria for the interpretation of HTS-BCG results

High throughput sequencing,

bioinformatics and computational

genomics (HTS-BCG)

Standard Reference Materials?

Traditional concepts don’t work here

Needs fresh thinking to ensure that when such

methods are used, the results and interpretation are

consistent, wherever or by whom the analyses are

done

High throughput sequencing,

bioinformatics and computational

genomics (HTS-BCG)

Ad hoc group report – challenges related to

standardisation Systems & infrastructure for data capture, handling, archiving

and access need to be optimised and standardised

Standards for HTS platforms need to be developed and

incorporated into the OIE Manuals

HTS-BCG needs to be fully validated and quality assured for use

as a diagnostic tool

High throughput sequencing,

bioinformatics and computational

genomics (HTS-BCG)

Ad hoc group report – recommendations related

to standardisation OIE should develop and adopt standards in the Manuals for

HTS-BCG

OIE should convene an ad hoc group which (inter alia) should

recommend standard approaches for harmonisation and

interpretation of HTS data

OIE should assess feasibility of extending WAHIS to incorporate

HTS data, with standards for data management.

Summary

Standardisation is essential for end-users to have

confidence in diagnostic test results

Great progress has been achieved with the

development of international written standards in

the OIE Manuals Work must continue, including incorporation of new technologies

Internationally recognised Standard Reference

Materials are few: We need more, but funding is difficult

May not apply to HTC-BCG technologies