**Interpretations of Detection and Quantitation Procedures Evaluation
Characteristics**

**[Introduction]{.underline}**

The Federal Advisory Committee on Detection and Quantitation Approaches
and Uses in Clean Water Act Programs (FACDQ) Technical Work Group (TWG)
has refined a matrix drafted by the FACDQ that documents detection and
quantitation procedural characteristics important in evaluating
procedures for various uses. The evaluation process is supported below
with an interpretation of each characteristic in the matrix and
specifics on how each procedure should be evaluated. This document will
maximize consistency among various reviewers of different procedures,
thereby providing a more reliable product for use by the FACDQ. However,
it is important to note that the matrix responses provided for the
September, 2005 FACDQ meeting reflect interpretations of individual TWG
members and do not reflect consensus of the TWG.

The TWG has deleted several of the procedural entries originally
introduced by the FACDQ. The LOD, CRV, MDV, IIAG and LOQ entries were
removed because they represent definitions for detection and
quantitation rather than actual procedures. The evaluation approach
identified by the FACDQ requires, for the most part, that a procedure be
available for comparison to the characteristics of the matrix. The Navy
Uncertainty Estimation Document was found to fall short of a true
description of a detection or quantification limit procedure. However
many of the concepts of this document may be useful to the FACDQ in
future efforts. The OSW quantitation approach, although not much more
than a definition in its present form was retained in the matrix because
of its current regulatory importance. These changes will help conserve
resources without compromising information.

The FACDQ TWG added the Osborn Lab QC detection procedure to the matrix
because its characteristics were not adequately represented by other
procedures. Although both the ACIL and the Consensus Group Detection
Limit procedures are implementations of the ISO/IUPAC approach to
detection, it was brought to the TWG's attention that the Water Research
Centre also had a procedure which implemented ISO/IUPAC. Thus, for
completeness, this was added to the matrix.

The procedure evaluation characteristics follow.

**[Measurement Quality Objectives]{.underline}**

Bias **-** Is bias explicitly derived by the procedure? (Y/N)

Precision - Is precision explicitly derived by the procedure? (Y/N)

\% False Positives - Does the procedure provide for selection of a Type
I error tolerance limit? (NA/Y/N)

\% False Negatives - Does the procedure provide for selection of a Type
II error tolerance limit? (NA/Y/N)

Qualitative Criteria Considered - Does the procedure require that
qualitative identification take place at the determined detection or
quantitation limit? (NA/Y/N)

Uncertainty Calculated - Does this procedure include a protocol or
requirement to calculate the confidence interval for the parameter in
question (Lc, Ld, Lq)? (Y/N)

Concentration Estimate Uncertainty -- Does the procedure provide
estimates of bias and/or precision as a function of concentration? (Y/N)

**[Evaluation of Method Performance]{.underline}**

Limit Evaluation Frequency - At what frequency does the procedure
specify that detection or quantitation limits are to be determined?
(Response options are: not specified, once, monthly, annual, on-going,
other (specify))

Data Generation Frequency -- How frequently does the procedure require
data to be generated to support development of detection and
quantitation limits? (Response options are: not specified, once,
monthly, annual, on-going, other (specify))

Reflects Routine Performance - Does the procedure yield detection or
quantitation limits that are reflective of routine test method
performance (when executed by qualified staff in the absence of matrix
effect, which are addressed below)? (Y/N)

Addresses Matrices -- Does the procedure describe how to modify a
detection or quantitation limit for applicability to real world samples?
(Y/N)

Evaluates Entire Test Method - Does the procedure evaluate the entire
test method including sample preparation and clean-up steps? Respond
with "NC" if the procedure does not evaluate the entire test method but
could be modified to evaluate the entire test method and footnote effort
required for this modification. (Y/N/NC)

Addresses Recovery - Does the procedure explicitly adjust or account for
impacts of recovery on analytical results? Respond with "NC" if the
procedure does not adjust or account for impacts on recovery but could
be modified to do so and footnote effort required for this modification.
(Y/N/NC)

Consistent or Chronic Blank Bias Addressed - Does the procedure
explicitly adjust or account for situations where method blanks always
return a non-zero result/response (e.g. defects in calibration or
consistent or chronic contamination of laboratory blanks). Respond with
"NC" if the procedure does not adjust or account for situations where
method blanks always return a non-zero result/response but could be
modified to do so and footnote effort required for this modification.
(Y/N/NC) Comment: need to clarify what is being asked and why.

Intermittent Blank Contamination - Does the procedure explicitly adjust
or account for situations where method blanks are intermittently
contaminated? Respond with "NC" if the procedure does not explicitly
adjust or account for situations where method blanks are intermittently
contaminated but could be modified to do so and footnote effort required
for this modification. (Y/N/NC). Comment: Is this characteristic
applicable to detection /quantitation procedures?

Non-Zero Results - Does the procedure adjust for results that are less
than zero? Respond with "NC" if the procedure does not adjust for
results that are less than zero but could be modified to adjust for
results that are less than zero and footnote effort required for this
modification. (Y/N/NC/NA) Comment: Based on IUPAC/ISO definitions where
a result is equal to sample response minus the blank response, is this
characteristic necessary?

**[Prescriptive\\Descriptive]{.underline}**

Prescriptive - Are specific, numeric performance benchmarks specified in
the procedure in order to demonstrate and maintain proficiency? (Y/N)

*or*

Descriptive - Is the procedure intended to measure the current
performance of the laboratory with regard to detection or quantitation
limits, regardless of performance benchmarks? (Y/N)

Bias - What is the limit for bias specified (either explicitly or by the
user) in the detection procedure? (If a limit is not specified, enter
'None'.)

Precision - What is the limit for precision specified (either explicitly
or by the user) in the quantitation procedure? ( If a limit is not
specified, enter 'None'.)

\% False Positives - What is the default value (in percent) of false
positive results (Type I errors) defined in the procedure? (If the
frequency is not addressed, enter either 'NA' or 'None' depending on the
procedure.)

\% False Negatives - What is the default value (in percent) of false
negative results (Type II errors) defined in the procedure? (If the
frequency is not addressed, enter either 'NA' or 'None' depending on the
procedure.)

**[Degree of Procedural Complexity]{.underline}**

Data Processing - What is the degree of complexity associated with
processing analytical test method data to compute or determine detection
or quantitation limits? (Rate from 1 to 10; 1 representing high
complexity, 10 representing low complexity.)

Laboratory Procedures - What is the degree of complexity (or work)
associated with laboratory activities required to compute or determine
detection or quantitation limits? (Rate from 1 to 10; 1 representing
high complexity, 10 representing low complexity.)

Is it a Clearly Written Procedure - Is the procedure written is such a
way that it will be uniformly interpreted and implemented by qualified
laboratory staff? (Y/N)

Can the Procedure be Clearly Written - Can the procedure be revised or
re-written to yield a version that would be uniformly interpreted and
implemented by qualified laboratory staff? (If answered 'Y' to previous
question, enter 'NA' or 'N')

Ability to Communicate Concepts - Can the concepts embodied by the
procedure be communicated in an effective manner to all interested
stakeholders? (Rate from 1 to 10; 1 being very difficult to communicate
the concepts, 10 being easy to communicate the concepts.)

**[Relative Cost]{.underline}** - What is the relative cost of the
procedure? (Rate from 1 to 10; 1 representing highest relative cost, 10
representing lowest relative cost.)

**[Interlaboratory Procedure]{.underline}**

As Written - Does the procedure account for interlaboratory variability
in the determination of detection or quantitation limits? (Y/N)

Could be Written as - Could the procedure be written to account for
interlaboratory variability in the determination of detection or
quantitation limits? (If answered 'Y' to previous question, enter 'NA'
or 'N')

**[Relative Implications]{.underline}** - What is the relative impact of
implementing the procedure on existing CWA programs? (Rate from 1 to 10;
N/A for no impact; 1 for high impact, 10 for low impact.)

**[Procedural Properties]{.underline}**

Detection - What measure is used to define detection? (L~c~, L~d~,
Other, NA, Unknown)

Quantitation - What measure is used to define quantitation? (L~Q~, %RSD,
NA, Other, Unknown)

Can be Evaluated with Existing Data - Can the detection or quantitation
procedure be evaluated using available, existing data? (Y/N)

Has been Evaluated with Existing Data - Has existing data been used to
evaluate the detection or quantitation procedure? (Y/N/unknown)

One Size Fits All - Is the procedure applicable equally to all
laboratories and test methods? (Y/N)

Flexibility for Each - Does the procedure allow flexibility to
accommodate various laboratory or test methodology considerations? (Y/N)

**[Data Types]{.underline}**

Censored Methods - Can the procedure explicitly handle data generated
using censored methods (as defined in the Glossary document)? (Y/N)

Uncensored Methods - Can the procedure explicitly handle data generated
using uncensored methods (as defined in the Glossary document)? (Y/N)

**[Defensibility]{.underline}**

Scientific - Do you judge the procedure to be scientifically defensible?
(Y/N)\*

Legal - Do you judge the procedure to be legally defensible? (Y/N)\*

\* The FACDQ TWG does not plan on addressing these characteristics
directly given that they are policy oriented; these characteristics
should therefore be addressed by the FACDQ.