calculateZPrime: Calculate Z'-factor of assay quality

In MALDIcellassay: Automated MALDI Cell Assays Using Dose-Response Curve Fitting

Calculate Z'-factor of assay quality

Description

Calculate Z'-factor of assay quality

Usage

calculateZPrime(res, internal = TRUE, nConc = 2)

Arguments

res	Object of class MALDIassay
internal	Logical, currently only the internal implementation, using nConc top and bottom concentrations, is implemented.
nConc	Numeric, number of top and bottom concentrations to be used to calculate the pseudo positive and negative control. Only used if internal is TRUE

Details

The most common way to measure the quality of an assay is the so-called Z'-factor, which describes the separation of the positive and negative control in terms of their standard deviations \sigma_p and \sigma_n. The Z'-factor is defined as Ji-Hu Zhang et al., A simple statistical parameter for use in evaluation and validation of high throughput screening assays.

Z' = 1 - (3 * (\sigma_p+\sigma_n))/|\mu_p-\mu_n|

where \mu_p and \mu_p is the mean value of the positive (response expected) and negative (no response expected) control, respectively. Therefore, the assay quality is independent of the shape of the concentration response curve and solely depend on two control values.

Note, if internal is set to TRUE, the nConc highest concentrations are assumed as positive control, whereas the nConc lowest concentrations are used as negative.

Value	Interpretation
Z' ~ 1	perfect assay
1 > Z' > 0.5	excellent assay
0.5 > Z' > 0	moderate assay
Z' = 0	good only for yes/no response
Z' < 0	unacceptable

Value

Numeric vector of Z'-factors.

Examples

# see example for `fitCurve()` to see how this data was generated
data(Blank2022res)
calculateZPrime(Blank2022res, nConc = 2)       
 

MALDIcellassay documentation built on Sept. 11, 2024, 8:29 p.m.