Reportable Values

To achieve "reportable values" for your assays, you need to perform combination calculations of your independent biological assays. The combination calculation of PLA 3.0 aggregates the data of independent assay runs into a combination calculation.

Combination of Independant Assay Results

The European Pharmacopoeia and the US Pharmacopeia describe different methods of combination calculations for independent assay results to obtain reportable values for the potency. PLA supports all different weighting methods for combination calculations. PLA also supports automatic data aggregation of independent assay data.

  • Unweighted Combination
  • Homogeneously Weighted Combination
  • Heterogeneously Weighted Combination according to European Pharmacopoeia, chapter 5.3
  • Heterogeneously Weighted Combination according to US Pharmacopeia <111>
  • Heterogeneously Weighted Combination according to US Pharmacopeia <1034>

Grouping of Calculations

PLA 3.0 also supports grouping of combination calculations. 

Example: consider two independent quantitative response assays with two test samples in each assay: Assay 1 contains test samples for Product A and Product B. Assay 2 contains test samples for the same products. In a grouped analysis you will receive two separate combination calculations. One for Product A as well as one for Product B.

Test System

You can set up acceptance tests for the calculation results of the combination calculation.

Microbial Assays for Antibiotics Package

The Microbial Assays for Antibiotics Package provides its own document type for combination calculations of independent cylinder-plate or turbidimetric assays. Aggregate such assays into the document to obtain the estimated combined potency for each combination group. Acceptance tests cover the specific values of this method.


  • Example Combination of Assay Results (Detail Report from PLA 3.0) 50 KB
    Grouped combination calculation of potency results of five independent assays.
  • Sample Report for a combination of microbial assays 49 KB
    Example combination of microbial assay documents. Cylinder-plate assays (based on USP <81>) are aggregated to determine the combined potency. In addition, test samples from the original assay documents are put into combination group 1 and 2 respectively. This results in a separate analysis for each group. The test system includes tests on the combined potency, the confidence interval of the estimated combined potency, and the CV (%) of the absolute potency values.