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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No literary matter in The Clinical Biochemist — Reviews is to be reproduced, stored in a retrieval system or transmitted in any form by electronic or mechanical means, photocopying or recording, without permission. Selection and analytical evaluation of methods with statistical techniques.

You should contact the package authors for that. You can download and open this file to your own computer but DRM prevents opening this file on another computer, including a networked server. Add the following s2 to your website. The reader is referred to the CLSI documents for details.

While the term precision relates to the concept of variation around a central value, imprecision is actually what is measured.

Evaluating Assay Precision

The procedures are designed for manufacturers or developers of clinical laboratory measurement methods, and for pe05 of those methods who wish to determine their own performance capabilities or to verify claims from a manufacturer.

The EPA2 protocol is similar except that the experiment is undertaken with three replicates over five days for at least two levels. Finally, we can calculate the total or within-laboratory SD s l using the equation:. 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. The assessment is performed on at least two levels, as precision can differ over the analytical range of an assay.


Within-Laboratory Precision Finally, we can calculate a total or within-laboratory SD s l using the equation: When undertaking the assessment the data must be assessed for outliers, which are considered to be present if the absolute difference between replicates exceeds 5. User verification of performance for precision and trueness; approved guideline. If an outlier is found the pair should be rejected and the cause investigated and resolved before repeating the run.

For example, on day 1 the average of the three values is 2. As the period of assessment is quite short, the total SD or within-laboratory SD derived from these experiments should not generally be used to define ep055 limits for internal quality control. Description Usage Format References. Embedding an R snippet on your website.

For more information on customizing the embed code, read Embedding Snippets. However, for a method developed in-house a higher level of proof is required to validate the method, in which case EPA2 would be the appropriate guideline to use.

For n measurements we have:. For a normal distribution the measure of imprecision is the standard deviation SD. This article has been cited by other articles in PMC. Instead total precision within a laboratory within-laboratory precision will be assessed. Marginal Effects for Model Objects. z2


Evaluating Assay Precision

If this is true then using the principle of analysis of variance components:. Table 3 shows the results of the same calculation for the remaining days. The page or its content looks wrong. Author information Copyright and License information Disclaimer.

For the purposes of this example the results of only a single level are shown Table 1. I can’t find what I’m looking for. 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.

Included are guidelines for the duration, procedures, materials, data summaries, and interpretation techniques that are adaptable for the widest possible range of analytes and device complexity. The figure of 5. Note, some authors refer to total variation as just the between-run component instead of combined between-run and within-run shown above.

Standards Subsctiption may be the perfect solution.

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