Question: Error in drm() Fitting dose-response models using 4PL
gravatar for mschmidt
11 months ago by
mschmidt10 wrote:

I want to use a R script (the beginning below) to calculate ELISA results. My ELISA kit has 5 standards, and sample result is (the first standard is 'zero' but it need to be changed into non-0)

OD conc 1.16544997692108 0.000001 0.861099988222122 0.25 0.54805001616478 1 0.344400003552437 4 0.112999998033047 16

library (drc)
###copy data for standards from excel (header – OD, conc) in windows use paste function
stdcrvdata <- read.table(pipe("pbpaste"), sep="\t", header=T) 
stdcrvdata$logconc <-log10(stdcrvdata$conc)# log10 from conc
plot(stdcrvdata$logconc, stdcrvdata$OD, main="log standard curve", xlab="x=log(conc)", ylab="y=OD")
fit<-drm(formula =   OD ~ logconc , data = stdcrvdata, fct = LL.4())

the last line of the script (fitting) results with error

Error in optim(startVec, opfct, hessian = TRUE, method = optMethod, control = list(maxit = maxIt, : initial value in 'vmmin' is not finite Error in drmOpt(opfct, opdfct1, startVecSc, optMethod, constrained, warnVal, : Convergence failed

how to fix that? The script works when used for 9-standard set.

error R fitting • 396 views
ADD COMMENTlink modified 9 months ago by Biostar ♦♦ 20 • written 11 months ago by mschmidt10
Please log in to add an answer.


Use of this site constitutes acceptance of our User Agreement and Privacy Policy.
Powered by Biostar version 2.3.0
Traffic: 763 users visited in the last hour