ASTM D7783-13
Standard Practice for Determination of the 99 %/95 % Critical Level (WCL) and a Reliable Detection Estimate (WDE) Based on Within-laboratory Data

Standard No.

ASTM D7783-13

Release Date

2013

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D7783-21

Latest

ASTM D7783-21

Scope

5.1 Appropriate application of this practice should result in a WQE achievable by the laboratory in applying the tested method/matrix/analyte combination to routine sample analysis. That is, a laboratory should be capable of measuring concentrations greater than WQE_Z8201;%, with the associated RSD equal to Z8201;% or less.

5.2 The WQE values may be used to compare the quantitation capability of different methods for analysis of the same analyte in the same matrix within the same laboratory.

5.3 The WQE procedure should be used to establish the within-laboratory quantitation capability for any application of a method in the laboratory where quantitation is important to data use. The intent of the WQE is not to impose reporting limits. The intent is to provide a reliable procedure for establishing the quantitative characteristics of the method (as implemented in the laboratory for the matrix and analyte) and thus to provide the laboratory with reliable information characterizing the uncertainty in any data produced. Then the laboratory may make informed decisions about censoring data and has the information necessary for providing reliable estimates of uncertainty with reported data.

1.1 This practice establishes a uniform standard for computing the within-laboratory quantitation estimate associated with Z % relative standard deviation (referred to herein as WQE_Z8201;%), and provides guidance concerning the appropriate use and application.

1.2 WQE_{Z %} is computed to be the lowest concentration for which a single measurement from the laboratory will have an estimated Z8201;% relative standard deviation (Z8201;% RSD, based on within-laboratory standard deviation), where Z is typically an integer multiple of 10, such as 10, 20, or 30. Z can be less than 10 but not more than 30. The WQE_{10 %} is consistent with the quantitation approaches of Currie (1)² and Oppenheimer, et al (2).

1.3 The fundamental assumption of the WQE is that the media tested, the concentrations tested, and the protocol followed in the developing the study data provide a representative and fair evaluation of the scope and applicability of the test method, as written. Properly applied, the WQE procedure ensures that the WQE value has the following properties:

1.3.1 Routinely Achievable WQE Value—The laboratory should be able to attain the WQE in routine analyses, using the laboratory‘s standard measurement system(s), at reasonable cost. This property is needed for a quantitation limit to be feasible in practical situations. Representative data must be used in the calculation of the WQE.

1.3.2 Accounting for Routine Sources of Error—The WQE should realistically include sources of bias and variation that are common to the measurement process and the measured materials. These sources include, but are not lim......

ASTM D7783-13 Referenced Document

• ASTM D1129 Standard Terminology Relating to Water
• ASTM D2777 Standard Practice for Determination of Precision and Bias of Applicable Methods of Committee D-19 on Water
• ASTM D6091 Standard Practice for 99 %/95 % Interlaboratory Detection Estimate (IDE) for Analytical Methods with Negligible Calibration Error
• ASTM D6512 Standard Practice for Interlaboratory Quantitation Estimate
• ASTM D7510 Standard Practice for Performing Detection and Quantitation Estimation and Data Assessment Utilizing DQCALC Software, based on ASTM Practices D6091 and D6512 of Committee D19 on Water
• ASTM E1763 Standard Guide for Interpretation and Use of Results from Interlaboratory Testing of Chemical Analysis Methods

ASTM D7783-13 history

• 2021 ASTM D7783-21 Standard Practice for Within-laboratory Quantitation Estimation (WQE)
• 2013 ASTM D7783-13 Standard Practice for Determination of the 99 %/95 % Critical Level (WCL) and a Reliable Detection Estimate (WDE) Based on Within-laboratory Data
• 2012 ASTM D7783-12 Standard Practice for Within-laboratory Quantitation Estimation (WQE)