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I N S I D E L A B O R A T O R Y M A N A G E M E N T

© A O A C I N T E R N A T I O N A L

N O V E M B E R / D E C E M B E R 2 0 1 4

21

Introduction

Many different systems have been

designed to evaluate methods. AOAC

INTERNATIONAL is well-known for

its

Official Methods of Analysis

SM

based on the traditional collaborative

study. The AOAC collaborative study

format has been adopted by many

organizations, most notably the United

Nations-sponsored

Codex Alimentarius

and the International Organization for

Standardization (ISO). Over the years,

AOAC

Official Methods

became the

“gold standard” for methods of analysis

for food, commodities, and water. In the

United States, the U.S. Code of Federal

Regulations directs the U.S. Department

of Agriculture and U.S. Food and Drug

Administration to use AOAC

Official

Methods

. Many AOAC

Official Methods

have been incorporated by reference

into

Codex Alimentarius

food standards.

The requirements for a collaborative

study validation of quantitative chem-

istry methods were codified by AOAC,

ISO, and the International Union of

Pure and Applied Chemistry (IUPAC) in

1987. The guidelines were subsequently

published by AOAC as the

Guidelines

for Collaborative Study Procedure to

Validate Characteristics of a Method

of Analysis

(1, 2). These guidelines

are commonly referred to as the “har-

monized protocol.” The harmonized

protocol was revised once in 1993, and

again in 1994. The harmonized protocol

was adopted by AOAC as the guideline

for the AOAC

Official Methods

program

in 1995 (3).

The hallmark of the harmonized

protocol is the requirement of valid data

from a minimum of eight laboratories

after the removal of outliers (1). As a

result of this requirement, most method

developers try to recruit a minimum of

10 collaborators, in case one or two

collaborators fail to complete their

analyses, or if the results from some of

the laboratories are determined to be

statistically inconsistent with the other

results (“outlier”).

Alternative Pathway

Between 1991 and 2000, an aver-

age of 28 collaborative studies per year

were completed, written, reviewed,

and approved as

Official Methods

. The

number of

Official Methods

approv-

als began declining in 2001, and by

2010 the number of approved

Official

Methods

diminished to three or four per

year. In early 2011, the AOAC Board

of Directors organized a presidential

task force, consisting of board mem-

bers who previously served as chairs of

the Official Methods Board (OMB), to

determine the causes for the decline in

Official Methods

output and to consider

ways to improve the

Official Methods

process.

After much consideration, the task

force made several recommendations:

1. AOAC should establish vol-

untary consensus standards,

Standard Method Performance

Requirements

SM

(SMPRs), for First

Action

Official Methods of Analysis

.

2. SMPRs are voluntary consensus

standards that contain minimum per-

formance requirements for methods.

3. Expert review panels (ERPs) should

assess candidate methods using the

performance requirements in SMPRs

to ensure that adopted First Action

Official Methods

are fit for the

purpose.

4. First Action

Official Methods

can be

adopted by an ERP with or without

collaborative study data.

5. The reproducibility of First Action

Official Methods

should be dem-

onstrated prior to adoption as

Final Action

Official Methods

.

(Reproducibility refers to data from

multiple laboratories using common

samples. Repeatability refers to

repeated analysis of a sample within

a single laboratory.)

6. Alternate types of reproducibility

data, such as proficiency testing

data, may be used in lieu of the

traditional collaborative study,

provided that the alternative data

demonstrates adequate method

reproducibility of “similar magni-

tude” to the traditional collaborative

study (4).

Collectively, these recommenda-

tions are known as the “Alternative

Pathway.” The Alternative Pathway

model was adopted by the AOAC Board

of Directors in March 2011 (5). Under

the Alternative Pathway, a method

may be designated as a First Action

Official Method

based on the judgment

of an ERP. First Action

Official Methods

remain as First Action for a period of

no more than 2 years. During the First

Action period, the method will be used

in laboratories, and method users will

be asked to provide feedback on the

performance of the method. The presid-

ing ERP will monitor the performance

of the method, and at the completion of

the 2-year First Action period, at which

time reproducibility data is expected,

determine whether the method should

be recommended to the OMB for adop-

tion as an AOAC Final Action

Official

Method.

This paper examines other

approaches that could potentially be

considered to generate suitable data

that could be deemed equivalent to

those generated in the past through a

well-organized collaborative study.

Fitness-for-Purpose Model

A collaborative study serves several

functions:

1. determines the inter-

(Continued on page 22)

T

his paper examines other approaches that

could potentially be considered to generate

suitable data that could be deemed equivalent

to those generated in the past through a well-

organized collaborative study.

138