I have what might be a very basic question: I want to run an NCA including both parent and metabolite. When entering dose information, should a row for metabolite be included, with a dose value of zero? Or should the dose information pertain only to parent (ie. no rows included for metabolite in the dosing information section). I am running Phoenix WNL v 6.1. Thanks in advance for any help, Joi
Hi Joi, It depends how you have your data set up. It sounds like your data is ‘stacked’ so that you need to use analyte as a sort variable; e.g. Subject analyte Time Conc 1 parent 0 0 1 parent 0.25 0.230243 1 parent 0.5 0.509471 … 1 parent 24 0.089143 1 metab 0 0 1 metab 0.25 0.043 1 metab 1 0.094 … 2 parent 0 etc. Then Phoenix will indeed be expecting a dose for that profile; however what you choose to enter her isopen to debate, some people enter ZERO as they don’t know the actual dose, other use the parent dose value but then later calculate and discuss the proportion that was converted. Personally, if I did not have a dosing sheet already created I would check the box “use internal worksheet” and then uncheck any identifiers not needed to specify different doses, i.e.if I was going to enter a dose of 25 for parent and 0 for metabolite, I would uncheck subject in the example set I gave 
which will give the resulting dosing upon preview 
testing a moderated user