correct.loq {qpNCA} | R Documentation |
Impute Concentrations Below the Limit of Quantitation
Description
Imputes LOQ values according to the chosen LOQ substitution rule.
Usage
correct.loq(
x,
by = character(0),
nomtimevar = "ntad",
timevar = "time",
depvar = "dv",
bloqvar = "bloq",
loqvar = "loq",
loqrule = 1
)
Arguments
x |
input dataset name contains all uncorrected data, including LOQ |
by |
column names in x indicating grouping variables |
nomtimevar |
variable name containing the nominal sampling time after dose |
timevar |
variable name containing the actual sampling time after dose |
depvar |
variable name containing the dependent variable (e.g., concentration) |
bloqvar |
variable name containing the BLOQ flag (0: no, 1: yes) |
loqvar |
variable name containing the LOQ value |
loqrule |
rule number to be applied to the LOQ values in the curve. x$loqrule overrides if provided
|
Details
Imputations will be applied to the original depvar (no new concentration variable will be created).
Value
A dataset with imputed BLOQ concentrations using the chosen imputation rule
Examples
library(magrittr)
library(dplyr)
library(qpNCA)
x <- Theoph
ntad <- c(0,0.25,0.5,1,2,4,5,7,9,12,24)
for(i in 1:nrow(x)){
time <- x$Time[[i]]
delta <- abs(ntad - time)
best <- min(delta)
index <- match(best, delta)
nom <- ntad[[index]]
x$ntad[[i]] <- nom
}
rm(list = c('time','delta','best','index','nom', 'i','ntad'))
x %<>% rename(time = Time, dv = conc)
x %<>% mutate(bloq = ifelse(dv==0,1,0), loq = 0.01, tad = time, loqrule = 1,
subject=as.numeric(Subject), ntad=as.numeric(ntad))
x %>% head
x %<>% correct.loq('subject')
x %>% head