Found in most body tissues
Elevation can occur as a result of cellular rupture (different isozymes can specify tissue type involved)
Cardiac - Demand ischemia, myocarditis
Pulmonary - pulmonary embolism
GI - hepatitis, small or large bowel obstruction
Hematologic - hemolytic process, ineffective erethropoiesis
Other - pregnancy, cancer, infection, systemic autoimmune disorders
Cardiac - Demand ischemia, myocarditis
Pulmonary - pulmonary embolism
GI - hepatitis, small or large bowel obstruction
Hematologic - hemolytic process, ineffective erethropoiesis
Other - pregnancy, cancer, infection, systemic autoimmune disorders
Liver function tests
Cardiac enzymes
HIV testing 
Cardiac ultrasound
ECG 
Urine toxicology screen
Microbiology 
Biliary ultrasound