The other thing that comes to mind, if indeed it WAS liver blood that was used to assess the levels, is that those levels are likely to have come from Allison's normal dose of Zoloft from the last time she took it - probably in the evening. There is no need to introduce other theories about her being forced to take more.
Just wondering, would these levels be in a normal blood test or would this be a special request blood test? The reason I ask because I have blood tests quite a bit and my Dr can always go back and see what my iron levels have been the past year on his computer etc..
If Allison did go to Kenmore Clinics (like GBC saw a Dr the following day) then they may have her 'normal' levels on file.