Professionally I would NOT make that statement at this time just state that no caustic chemicals were present (my investigative "defense" for that statement would be the condition of her GI/Resp. tracts & oral cavity.). Without a doubt, a urine screen for DOAs (drugs of abuse) was run ASAP, however there are many other classifications of 'script or OTC drugs that can kill and these panels take longer to evaluate. Suffocation/asphyxia (manual or by accident) CAN present with petechial hemorrhage in the eye & on the facial skin, no way would any LE/or ME introduce that information to the public!
Would antifreeze poisoning be quickly detectable? I can picture a child who perhaps is not normally allowed to have soda seeing a container of inviting yellow-green drink...