1. Statistical Reference Guide
  2. Measurement systems analysis (MSA)
  3. Detection capability

Verifying a detection capability claimTest if the results of a verification study are consistent with a manufacturer's limit of blank, limit of detection, or limit of quantitation claim.

A detection capability claim is verified by measuring a small number of samples in replicate over several days, counting the proportion of results that are consistent with the claim, and testing if that proportion is less than 95%. A result is consistent with the claim when:

  • For a limit of blank claim, a blank sample result is less than or equal to the claimed limit of blank.
  • For a limit of detection claim, a low level sample result is greater than or equal to the limit of blank.
  • For a limit of quantitation claim, a sample result is within the allowable error of the sample's assigned value.

Before you start, add a column to the dataset that classifies each result as consistent with the claim or not, for example using an Excel formula such as =IF(B2<=LoB,"Pass","Fail"). Alternatively, count the results in each category and enter the counts in frequency form.

  1. Select a cell in the dataset.
  2. On the Analyse-it ribbon tab, in the Statistical Analyses group, click Distribution, and then click Binomial Exact.
    The analysis task pane opens.
  3. In the Y drop-down list, select the variable that classifies each result.
  4. Optional: If the data are in frequency form, in the Frequency drop-down list, select the frequency count variable.
  5. In the Event drop-down list, select the category for results consistent with the claim.
  6. In the Hypotheses drop-down list, select the null hypothesis that the proportion is greater than or equal to the hypothesized value against the alternative hypothesis that it is less than the hypothesized value.
  7. In the Hypothesized value edit box, type 0.95.
  8. In the Significance level edit box, type 5%.

    CLSI EP17-A2 requires a minimum of 20 results.

  9. Click Calculate.

If the null hypothesis is not rejected, the results are consistent with the claim and the claim is verified. If the null hypothesis is rejected, the proportion of results consistent with the claim is significantly less than 95% and the claim is not verified.

Available in
Method Validation Edition Ultimate Edition

From the Statistical Reference Guide for Analyse-it 6.24.0: https://analyse-it.com/docs/user-guide/measurement-systems-analysis/detection-capability/verifying-detection-capability-claim

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