I am measuring cytokines using multiplex assay. Some of the proteins have out of range (OOR) results (either < or > the standard curve values). I want to fill these missing data with actual numbers, if possible, and reanalyze my data.
Unless you managed to do multiple dilutions of your samples and have one dilution for each of the proteins where the values were in range, this is not possible. Values that are below the limit of quantification and above the linear range cannot be quantified accurately. The OOR values you have cannot be extrapolated. Whenever doing multiplex ELISA, run at least 2 dilutions (one high and one low), so you can get values within range for all cytokines (at least in one of the dilutions).
No is the correct answer, as others have mentioned you need to titrate your sample to get a value that is within the range of the assay. I assume the problem you have struck is how to perform a statistical analysis when the data has no numerical value? Those samples that are below the LOD cannot be helped by further titration and they will have to be given an arbitrary value that is near zero. Your methods/data description should always explain how you made this analysis.
I agree with Simon Apte and Julie Joseph on their answers. The values that come back as >OOR or
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