Comparison between PLA 2.x and PLA 3.0
Find key differences between PLA 2.x and PLA 3.0, changes in concepts and architecture to support you in determining the impact when updating your PLA environment.
Assay data
-
PLA 3.0 stores assays in documents
A single document in PLA 3.0 has all definitions and raw data. The definitions are no longer distributed over several objects. The Quantitative response assay document within PLA 3.0 is the successor of the Assay, Standard, Preparation, and Control documents known from PLA 2.x.
For details on the handling of documents in PLA 3.0, see the Documents topic.
-
PLA 3.0 stores calculation results within the document
In PLA 2.0 and PLA 2.1, the calculation results were recreated with every reporting task, the calculated data was not stored within the database. In PLA 3.0, this behavior has changed such that assay documents now separate the calculation process from the reporting. This lets PLA 3.0 perform subsequent calculations with the results of the calculation.
Data structures
One of the main differences between PLA 2.x and PLA 3.0 is the redesign of the information structure.
PLA 2.x organized data in a hierarchy of projects, assays, and assay elements, namely standard, preparation and control (line) objects. This structure is highly flexible and has several advantages regarding practical handling. However, it also has severe disadvantages, which led to the development of the Quantitative response assay document type.
In the case of Quantitative response assay documents, all assay data including its results are kept in one single document. This document aims to calculate the potencies for one single assay run.
The main difference comparing the document to PLA 2.x is that PLA 3.0 only supports one single interpretation of the standard curve within one single assay. If the definitions of a PLA 2.x assay allow different interpretations of the standard (for example when automatic linear range detection is turned on with the 'Individual Range' option, two different ranges can be selected within PLA 2.x), this is no longer supported within PLA 3.0. In this case, the assay definitions need to be split per assay element.
For details about the handling of quantitative response assays in PLA 3.0, see the Quantitative response assays topic.
Statistical differences
PLA 3.0 comes with many more capabilities and lets you set up assays with a much more sophisticated setup.
From a statistical perspective, the main difference comes from the conceptual change of the assay perspective. PLA 3.0 calculates all assay elements with the same analytical setup. In PLA 2.x, the sample element controls the analytical setup. If the assay setup has varying analytical settings, PLA 3.0 has to split the assay.
The same conceptual change applies to the range optimizer option. In PLA 2.x, you could use this option to select different steps for the standard in linear parallel-line models. If you need to select different range areas for the standard in PLA 3.0, you also have to split the assays per sample.
In the case of non-linear regression, the precision of PLA 3.0 has been improved. In a well-behaved assay, this may lead to small differences in the estimated parameters and their standard errors. Usually, these deviations are very small. However, if the iteration number for non-linear regression is high (for example >50 iterations), this indicates an assay with a very shallow hyper-surface. In this case, the deviation can get larger. Especially the 5-parameter-fit might show this behavior. The reason for these differences is the application of different cut-off criteria during optimization.