GSTM1 and liver failure: According to University Hospitals of Leicester guidelines, high-risk patients are the following: Patients in shock (hypotension, confusion, dizziness, tachycardia, acidosis, prolonged capillary refill time), patients with active ongoing bleeding, patients with documented esophageal varices, liver failure, renal failure, heart failure or congenital heart disease, different types of coagulopathies, and also Hb < 8 mg/dL [1].