What is being tested?

Urea is a waste product formed from the breakdown of proteins which may include dietary proteins or proteins from the breakdown of muscles. Urea is excreted in urine. High urea level in blood indicates that the kidney is not excreting it properly or there is dehydration.

Creatinine is a waste product derived from muscles. Creatinine is removed from the body by the kidneys, which filter almost all of it from the blood and release it into the urine. This test measures the amount of creatinine in the blood. Creatinine is usually a more accurate marker of kidney function than urea.

Creatinine depends on the size of the person and muscle mass because of this creatinine concentrations will be slightly higher in men than in women and children.

Sodium is an electrolyte present in all body fluids. It is vital to normal body function, including nerve and muscle function. A sodium test measures the level of sodium in blood.

Potassium is an electrolyte which helps in transporting nutrients into cells and removing waste products out of cells. It is also important in muscle function as it helps in transmitting messages between nerves and muscles. A potassium test measures the amount of potassium in the blood.