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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Standards Subsctiption may be the perfect solution. Note, some authors refer to total variation as just the between-run component instead of combined between-run and within-run shown above.

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. You can download and open this file to your own computer but DRM prevents opening this file on another computer, including a networked server.

Table 2 shows the results of each of these calculations.

Evaluating Assay Precision

Need more than one copy? Care must be taken in knowing which term is being referred to. If this is true then using the principle of analysis of variance components: However, if the values achieved are greater than those reported by the manufacturer, a statistical test needs to be performed to determine whether this difference is statistically significant. Within-Laboratory Precision Finally, we can calculate the total or within-laboratory SD s l using the equation: The procedures are designed for manufacturers or e;05 of clinical laboratory measurement methods, and for users of those methods who wish to determine their own performance capabilities or to verify claims from a manufacturer.


Journal List Clin Biochem Rev v. The EPA2 protocol is similar except that the experiment is undertaken ep055 three replicates over five days for at least two levels. The next step is to calculate the variance for the daily means s b 2 using the equation. Clinical and Laboratory Standards Institute.

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As alluded to above, EPA2 is generally used to verify that a method is performing as is claimed by the manufacturer. You may delete a document from your Alert Profile at any time.

dp05 What can we improve? Repeatability Repeatability is estimated using the equation below. Using the example data eo05 assuming the claimed repeatability is an improbable CV of 1. Acknowledgments Special thanks to Amanda Caswell for her careful review of the manuscript.

Support Center Support Center. Estimating Precision When evaluating the precision of an assay, the trivial approach for estimating repeatability for any given level is to perform 20 replicate analyses in a single run on a single day.

Using the values from our example the mean of all the results is 1.

Introduction Part of the process of verifying or validating a method to confirm that it is suitable for use is an assessment of precision. User verification of performance for precision and trueness; approved guideline.

Evaluating Assay Precision

We have no amendments or corrections for this standard. For n measurements we have:. Elsevier Saunders; St Louis: Thus the variance of the daily means is:. When undertaking the assessment the data must be assessed for outliers, which are considered to be present if the absolute difference between replicates exceeds rp05.


Author information Copyright and License q2 Disclaimer. A spreadsheet for assisting with the calculations described in this article is available from the AACB web-site.

This article has been cited by other articles in PMC. If the repeatability and within-laboratory SD are less than that indicated by dp05 manufacturer, then the user has demonstrated precision consistent with the claim and no further calculations are required. Please first log in with a verified email before subscribing to alerts. Thus, factor ‘day’ is the top-level random factor variance componentfactor ‘run’ is nested within ‘day’.

Add to Alert PDF. These include pooled patient samples, quality control material, or commercial standard material with known values.

EPA2 should be used to validate a method against user requirements, and is generally used by reagent and instrument suppliers to demonstrate the precision of their methods. If QC material is being used for the precision assessment, it should be different to that used to control the assay.

Statements of opinion in AACB publications are those of the contributors. On day 1 the mean of the three replicates was 1.