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EP5-A2. ISBN Volume 24 Number ISSN Evaluation of Precision Performance of Quantitative Measurement. Methods; Approved. Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline, EP05A2E. Clinical and Laboratory Standards Institute (CLSI) document EPA2 describes the protocols for determining the precision of a method. The precision of a.

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EPA2 should be used to validate a method against user requirements, and is generally wp05 by reagent and instrument suppliers to demonstrate the precision of their methods.

Evaluating Assay Precision

Marginal Effects for Model Objects. The page or its content looks wrong. Thus the variance of the daily means is:.

For more information on customizing the embed code, read Embedding Snippets. Description Usage Format References. Repeatability Verification Value In ep50 to compare the estimated repeatability to a claimed value we can calculate the critical or verification value using the equation: For the purposes of this example the results of only a single level are shown Table 1.

Note that we can’t provide technical support on individual packages. A balance is created in the document between complexity of design and formulae, and a of operation.

Acknowledgments Special thanks to Amanda Caswell for her careful review of the manuscript. I have a suggestion. Open in a separate window.

Standards Subscriptions from ANSI provides a money-saving, multi-user solution for accessing standards. Part of the process of verifying or validating a method to confirm that it is suitable for use is an assessment of precision. CLSI now uses the term within-laboratory precision to denote the total precision within the same facility using the same equipment 1 and this term will be used for this concept throughout this paper.


Evaluating Assay Precision

For a22 normal distribution the measure of imprecision is the standard deviation SD. If the repeatability and within-laboratory SD are less than that indicated by the manufacturer, then the user has demonstrated precision consistent with the claim and no further calculations are required.

Author information Copyright and License information Disclaimer. For n measurements we have:. Australasian Association of Clinical Biochemists Website. Your Alert Profile lists the documents that will be monitored. NCCLS document EP5-A2, Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline – Second Edition provides guidance and procedures for evaluating the precision of in vitro diagnostic devices and includes recommendations for manufacturers in evaluating their devices and methods when establishing performance claims.

Standards Subsctiption may be the perfect solution. You may delete a document from your Alert Profile at any time. Using the example data and assuming the claimed repeatability is an improbable CV of 1. Table 2 shows the results of each of these calculations. The first replicate on day 1 is 2. Estimation of Repeatability and Within-Laboratory Precision The following example relates to the verification of performance of calcium according to EPA2 using a five day protocol.

As alluded to above, EPA2 is generally used to verify that a method is performing as is claimed by the manufacturer. Evaluation of precision wp05 of quantitative measurement methods.

The first step is to calculate the mean of the replicates for each day, then for each result subtract the mean for that day and square the resultant value. Summary When evaluating the precision of a method it is necessary to assess the repeatability within-run and the total or within-laboratory precision. National Center for Biotechnology InformationU. Reproducibility is at the other extreme and refers to the closeness of agreement between results of successive measurements obtained under changed conditions time, operators, calibrators, reagents, and laboratory.


CLSI document EPA2 describes the protocols that should be undertaken by the user to verify precision claims by z2 manufacturer. Proceed to Checkout Continue Shopping. Precision claims by a manufacturer should be tested at at-least two levels, by running three replicates over five days.

On 20 days two separate runs with two replicates of the same sample are measured. Statements of opinion in AACB publications are those of the contributors. Each level is run in duplicate, with two runs per day over 20 days, and each run separated by a minimum of two hours.

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There is some variation in the terminology used but for the purposes of this discussion, repeatability, also known as within-run precision, is defined as the closeness of agreement between results of successive measurements obtained under identical conditions.

Clinical and Laboratory Standards Institute. T is best calculated in a spreadsheet and is given by:. Similarly the within-laboratory precision is estimated by measuring a sample 20 rp05 over multiple days. Linnet K, Boyd JC. Add to Alert PDF.