Is there a blood work test I can ask Mom's Dr./ Neurologist to take to see if mom is being given a sedative?

My mom is constantly asleep during the week, on weekends she is wide awake , doing word finds, watching movies etc...
It was not til this past week where the home care taker came while I was giving Mom breakfast as I called in sick for work. She suddenly asked if I had given her medications.. I replied no, she is still having breakfast..
I hate to even think this but did cross my mind home care taker may be giving her a sedative, making her sleep all day..
Is there a blood work test her Neurologist can ask for and maybe see
if in fact she is being given something or not? Please help and thank you in advance.