Z-Primes (PC x NC)

The Z-Prime factor is a commonly used statistical parameter that describes the quality of an assay or a screening plate. It takes into account the separation and the variabilities of two controls (e.g. positive and negative control wells) and ranges from minus infinity to 1.

For groups of data (e.g. wells of plates) Z-Prime factors are calculated for two selected subsets (e.g. positive and negative control wells of a plate). Multiple positive and negative controls can be selected as subsets and the Z-Prime factors will be calculated for all combinations of these. For each group mean and standard deviation (or median and mad) are calculated for the selected subsets.

Z' = 1 - 3 * (sd(x[subset{positive}]) + sd(x[subset{negative}])) / |mean(x[subset{positive}]) - mean(x[subset{negative}])|
or
Z' = 1 - 3 * (mad(x[subset{positive}]) + mad(x[subset{negative}])) / |median(x[subset{positive}]) - median(x[subset{negative}])|

Literature: Zhang, J. et al., J Biomol Screen 1999; 4; 67
Wikipedia: Z-factor

Options

Group wells by
Select the column to define the groups (e.g. "barcode" for plate-wise Z-Prime factor).
Subset column / well annotation column
Column with well annotations (e.g. treatment)
Subset / Positive Control
Select subsets as positive controls for which means and sd (medians and mads) are calculated for each group.
Subset / Negative Control
Select subsets as negative controls for which means and sd (medians and mads) are calculated for each group.
Use robust statistics
Median and mad will be calculated instead of mean and sd.
Include
Select the columns for which Z-Prime factors will be calculated.

Input Ports

Icon
Input table

Output Ports

Icon
Table with Z-Prime factors

Views

This node has no views

Workflows

Links

Developers

You want to see the source code for this node? Click the following button and we’ll use our super-powers to find it for you.