A 30 year old male is brought into the ED by ambulance at 1100 hrs, and he is confused and having difficulty speaking. His wife is with him and provides an AMPLE history for you:
Allergies: None
Meds: Insulin (she is not sure when he last took it)
PMH: IDDM, Dx'd at age 12
Last meal: Unsure
Events surrounding: His wife complains that he has been drinking way too much lately, and yesterday he had been out on another of his "benders" with friends. He came home early this morning and was feeling nauseous, but they attributed it to the alcohol.
Upon questioning him, he complains of abdominal pain in the epigastric area and says he has vomited 3 times in the last two hours. While questioning him, you notice that his breath smells of stale booze, and he has deep and labored breathing.
On physical exam, you find the following:

Vitals: HR: 115 beats/min, BP: 90/50, RR: 32/min, Temp. 37.2 Centigrade
General appearance: Obese 30 year old male, obtunded
CVS: Normal S1, S2 with no extra sounds
Pulmonary: Chest clear to auscultation
Abdo: Normal bowel sounds. His abdomen is distended and he complains of pain when you palpate the epigastric area. Mild hepatomegaly is noted.
HEENT: Mucous membranes appear dry, otherwise normal
Neuro: Decreased LOC, E4V4M6 (14), CN's II-XII intact, normal sensory and motor exam, although he has difficulty ambulating.

You return to your preceptor and tell her your findings. She asks you what investigations you would like to order. Choose from the options below.