Back-transform an MBMM gate threshold

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