Why are kidneys so important?
Your kidneys are important because they do three essential things:
1. 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.
2. Kidneys remove waste products and help to balance the body's minerals
Many of the substances in the blood and other body fluids must be kept at the correct level for the body to function properly. For example, sodium (salt) and potassium are minerals that come from food. The body needs these minerals for good health, but they must be kept at certain levels. When the kidneys are working properly, extra minerals, such as sodium and potassium, leave your body in the urine. The kidneys also help to adjust the levels of other minerals, such as calcium and phosphate (which are important for bone strength, growth and other functions).
Your kidneys help remove waste products, such as urea and creatinine, from your 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. The creatinine level in the blood is a very useful measure of kidney function. It is measured by a simple blood test.
3. Kidneys produce hormones
Normal kidneys also make important chemicals in your body called hormones. These hormones circulate in the bloodstream like “messengers” and regulate blood pressure, red blood cell production and the calcium balance in your body.
Normal Blood Value Ranges
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. Every lab has different normal values for serum creatinine because their autoanalyzers are different. Every lab also has the option of providing male and female ranges because they do differ based on muscle mass. The values shown above were taken from a Canadian reference lab at the time this content was developed.
* 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.