Combination of microbial assays

Use Combination of microbial assays documents to aggregate data of samples contained in any number of microbial assay documents, apply confidence limits, check for outliers, perform combination of assays calculations, and define statistical tests.

Tip: Advanced analysis document types included in other PLA 3.0 add-ons, such as the Control Chart Package, provide additional features you may find useful.

About this document type

Microbial determinations of potency are susceptible to interassay variability. USP <81> recommends to use three or more independent determinations and combine results to receive reliable estimates of potency.

The calculations of the Combination of microbial assays document type lets you closely follow the guidelines laid out in USP <81>. You can analyze results across several assay documents, and document supplemental information.

For details on the calculation steps, see the Combination calculation topic.

To combine results that are distributed across several assay documents you set up a separate Combination of microbial assays document. In this document, you reference the assay documents that contain the samples whose data is to be included in the combination calculation.

Tip: You can identify assays of this document type by the icon in the upper right corner of the Content editor.

Document structure

Each Combination of microbial assays document has three sections, that is, Potency data, Analysis, and Documentation, plus one or more optional Comment sections.

Figure 1. Sections of a Combination of microbial assays displayed in the Content editor
Section Description

Documentation

Provide supplemental information on your advanced analysis that is needed for documentary purposes.

Potency data

  • Aggregate observation data of existing assays.

  • Organize observation data.

Analysis

  • Define confidence limits.

  • Apply outlier tests.

  • Define the statistical tests you need for your advanced analysis.

For details on the test system, see the Test system topic.

Comment

Provide more information on your assay.