Why Kidneys Are So Important
Your kidneys are important because they do three essential things:
Kidneys regulate water
For your body to work properly, it must contain just the right amount of water. One of the important jobs of the kidneys is to remove excess water from the body or to retain water when the body needs more.
Kidneys remove wastes
Many of the substances in the blood and body fluid must be kept at the correct level for the body to function properly. When the kidneys are working properly, excess minerals, such as sodium and potassium, are excreted from the body in the urine. The kidneys also help to regulate the levels of other minerals, such as calcium and phosphate, which are important for the formation of bone.
Normal Blood Value Ranges
Wastes, such as urea and creatinine, must also be removed from the body. Urea and other wastes are made when the body breaks down protein, such as meat. Creatinine is a waste product of the muscles. As kidney function decreases, the levels of urea and creatinine in the blood increase. Many waste products are toxic (poisonous) if they are not removed from the body fluids. For example, when certain drugs are taken, chemical wastes are produced which must be removed from the body by the kidneys.
The amount of each substance in the blood can be measured in several ways: for example, millimoles (mmol), micromols (μmol) or grams per litre of blood (g/L). The numbers in the table show the range of the normal levels of various substances in the blood of a healthy person.
Kidneys produce hormones
Normal kidneys also make important chemical messengers called hormones. These hormones circulate in the bloodstream and regulate some body functions such as blood pressure, the making of red blood cells, and the uptake of calcium from the intestine.
* The GFR, or glomerular filtration rate, is a blood-related lab test. It provides a useful measure of kidney function. Sometimes it is called the eGFR or estimated glomerular filtration rate.