"Maintaining healthy blood, including its continuous renewal, is essential to support its vast array of vital functions. Blood is healthy when it contains the appropriate amount of water and cellular components and proper concentrations of dissolved substances, such as albumin and electrolytes. As with all other tissues, blood needs macro- and micronutrients to optimally function. In the bone marrow, where blood cells are made, amino acids are required to build the massive amount of hemoglobin packed within every red blood cell, along with all other enzymes and cellular organelles contained in each blood cell. Red blood cells, similar to the brain, use only glucose as fuel, and it must be in constant supply to support red-blood-cell metabolism. As with all other cells, the cells in the blood are surrounded by a plasma membrane, which is composed of mainly lipids. Blood health is also acutely sensitive to deficiencies in some vitamins and minerals more than others. Blood tests are helpful tools in diagnosing disease and provide much information on overall health. Since blood is the conduit of metabolic products and wastes, measuring the components of blood, and particular substances in blood, can reveal not only the health of blood, but also the health of other organ systems. In standard blood tests performed during an annual physical, the typical blood tests conducted can tell your physician about the functioning of a particular organ or about disease risk. A biomarker is defined as a measurable molecule or trait that is connected with a specific disease or health condition. The concentrations of biomarkers in blood are indicative of disease risk. Some biomarkers are cholesterol, triglycerides, glucose, and prostate-specific antigen. The results of a blood test give the concentrations of substances in a person’s blood and display the normal ranges for a certain population group. Many factors, such as physical activity level, diet, alcohol intake, and medicine intake can influence a person’s blood-test levels and cause them to fall outside the normal range, so results of blood tests outside the “normal” range are not always indicative of health problems. The assessment of multiple blood parameters aids in the diagnosis of disease risk and is indicative of overall health status. Substances measured in typical blood tests include red-blood-cell count, hematocrit, white-blood-cell count, platelet count, pH, albumin, bilirubin, oxygen and carbon dioxide, hemoglobin, iron, magnesium, electrolytes, cholesterol, triglycerides, glucose, and hormones. These measurements can indicate oxygen-carrying capacity, anemia risk, the presence of infection, bleeding disorders, atherosclerosis risk, metabolic, kidney, and respiratory abnormalities, liver and kidney conditions, dehydration, protein deficiency, liver-function abnormality, respiratory or metabolic abnormality, magnesium deficiency, cardiovascular disease risk, diabetes risk, and many illnesses including diabetes and reproductive abnormalities."