Back-transform an MBMM gate threshold — mbmm_backtransform

Converts a threshold from the covariate scale used in the gate model back to the original biomarker scale.

Usage

mbmm_backtransform_threshold(
  threshold,
  center = 0,
  scale = 1,
  transform = c("identity", "log10", "log")
)

Arguments

threshold: Numeric threshold on the fitted gate-covariate scale.
center: Center used when standardizing the covariate.
scale: Scale used when standardizing the covariate.
transform: Transformation applied before standardization. One of "identity", "log10", or "log".

Value

Numeric threshold on the original biomarker scale.

Details

If the fitted covariate is a standardized variable

$$ z = \frac{x - \mu}{s}, $$

the model-scale threshold is first converted to

$$ x = \mu + sz. $$

An optional inverse transformation is then applied. For example, when the standardized covariate was constructed from log10(biomarker), use transform = "log10".

Examples

mbmm_backtransform_threshold(
  threshold = 1.2,
  center = 2,
  scale = 0.5,
  transform = "log10"
)
#> [1] 398.1072