The clinical presentation and presumed etiology of shock will dictate the diagnostic studies, monitoring modalities, and interventions used. The approach to each patient must be individualized; however, frequently performed laboratory studies include complete blood count; platelet count; electrolytes, blood urea nitrogen, and creatinine determinations; prothrombin and partial thromboplastin times; and urinalysis. Other tests commonly used are arterial blood gas, lactic acid, fibrinogen, fibrin split products, D-dimer, and cortisol determinations; hepatic function panel; cerebrospinal fluid studies; and cultures of potential sources of infection. A pregnancy test should be performed on all females of childbearing potential. No single laboratory value is sensitive or specific for shock. Other common diagnostic tests include radiographs (chest and abdominal), electrocardiographs, computed tomography scans (chest, head, abdomen, and pelvis), and echocardiograms. Beside US may also help determine the etiology of shock. The following are helpful in this assessment: subcostal cardiac view, inferior vena cava view, parasternal long-axis cardiac view, apical four-chamber cardiac view, right upper quadrant abdominal view, pelvic view, and abdominal aorta view.