The body uses glucose for energy. Urea is a waste product formed during the digestion of proteins and in urine is the vehicle for ridding the body of nitrogen. Blood urea is an indicator of kidney function. Creatinine also is a waste product formed during digestion. Normal levels in urine indicate the kidneys are effectively removing creatinine from the bloodstream.
Cholesterol is used to synthesize cell membranes, sex hormones, and some vitamins.
When blood cholesterol levels are high, excess cholesterol may be deposited on the inner walls of blood vessels, which leads to the formation of atherosclerotic plaques. Cholesterol levels may be reduced by lowering the fat and cholesterol content in the diet and by exercising. Their role is to transport excess cholesterol from the body to the liver, where it is removed from the bloodstream. This ratio indicates how much of the total cholesterol reading is composed of HDLs. A triglyceride is a fat.