They did a full toxicology screen, which would show most drugs, particularly neuroactive drugs. Antibiotics can slip under the radar of those, due to their short half-life in the system, which is why many antibiotics need to be taken 3 or 4 times a day - including amoxycillin. But the prescribing date on the amoxycillin packet (and the Maxolon) should give the police and pathologists a clue as to whether or not there would be likely to be any in her system.
The sertraline ("Zoloft") was specifically tested for, as they had found the packet in Allison's car, plus they knew she was on it anyway.
And speaking of the sertraline, the defence keep babbling on about "normal levels" being this or that - but they are referring to peripheral blood levels (like you'd get from a blood sample taken from the cubital vein - the one in front of your elbow). But the samples taken from Allison's body were from the liver and some liver tissue - and as I've pointed out before, the liver concentrates many drugs, including sertraline. This, plus post-moretem redistribution, gives much higher levels than a peripheral blood sample would have done - but they couldn't get peripheral blood due to the decomposition.
That's why Prof Olaf Drummer pointed out that the levels that WERE found were within the range that would be expected - in the liver - from somebody who had normal therapeutic levels in their system.
The problem is - the prosecution have to distil this point down to a couple of dot-point facts so that the jury, who would be non-medical, can see what the point actually is.
Thanks again Doc. Your guidance here is very much appreciated.