<P> A basic metabolic panel measures sodium, potassium, chloride, bicarbonate, blood urea nitrogen (BUN), magnesium, creatinine, glucose, and sometimes calcium . Tests focusing on cholesterol levels can determine LDL and HDL cholesterol levels, as well as triglyceride levels . </P> <P> Some tests, such as those that measure glucose or a lipid profile, require fasting (or no food consumption) eight to twelve hours prior to the drawing of the blood sample . </P> <P> For the majority of tests, blood is usually obtained from the patient's vein . Other specialized tests, such as the arterial blood gas test, 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 is also used to measure blood pH and bicarbonate levels for certain metabolic conditions . </P> <P> 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 . </P>

Medical term for a blood test to measure the levels of oxygen in the blood