Hello,
I am trying to fit my Elisa results (absorbance readings) to a standard
curve. To create the standard curve model, I performed a 4-parameter
logistic fit using the 'drc' package (ExpectedConc~Absorbance). This gave me
the following:
> FourP
A 'drc' model.
Call:
drm(formula = Response ~ Expected, data = SC, fct = LL.4())
Coefficients:
b:(Intercept) c:(Intercept) d:(Intercept) e:(Intercept)
1.336 6.236 85.521 59.598
> summary(FourP)
Model fitted: Log-logistic (ED50 as parameter) (4 parms)
Parameter estimates:
Estimate Std. Error t-value p-value
b:(Intercept) 1.33596 0.15861 8.42309 0.0011
c:(Intercept) 6.23557 3.18629 1.95700 0.1220
d:(Intercept) 85.52140 2.15565 39.67313 0.0000
e:(Intercept) 59.59835 5.18781 11.48815 0.0003
Residual standard error:
1.866876 (4 degrees of freedom)
Now that I have the 4 parameters, how do I fit the absorbance readings for
the analytical unknowns to the standard curve model (as to estimate the
concentrations of my unknown analytical samples)?
I can use the argument 'predict', but this predicts absorbance given
concentrations (y given x), I need to predict concentrations give absorbance
(x given y).
Thanks!
Chris
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