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
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© A O A C I N T E R N A T I O N A L
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N O V E M B E R / D E C E M B E R 2 0 1 4
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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.
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