Biochemical analysis
A basic metabolic panel measures sodium, potassium, chloride, bicarbonate, blood urea nitrogen (BUN), magnesium, creatinine, and glucose. It also sometimes includes calcium. Some blood tests, such as measuring glucose, cholesterol, or for STD screening requires fasting (or no food consumption) eight to twelve hours prior to the blood test. For the majority of blood tests, blood is usually obtained from the patient's vein. However, other specialized blood tests, such as the Arterialblood gas, require blood extracted from an artery. Blood gas analysis of arterial blood is primarily used to monitor carbon dioxide and oxygen levels related to pulmonary function. But, it is also used to measure blood pH and bicarbonate levels for certain metabolic conditions. While the regular glucose test is taken at a certain point in time, the glucose tolerance test involves repeated testing to determine the rate at which glucose is processed by the body.