1. Evaluation of Renal Function

2. Normal volumes and composition of electrolytes in various body fluid compartments are essential for maintenance of life. Maintenance of normal volumes and composition of electrolytes requires participation of various control mechanisms, and the role of the kidney is particularly important.

3. The most important function of the kidney is elimination of the waste products of metabolism, and this function is best represented by the glomerular filtration rate (GFR) The two most widely used markers of the adequacy of GFR are plasma concentrations of creatinine and urea nitrogen

4. Among the important parameters of normal body fluid composition are the concentrations of protons, sodium, and potassium.

5. Disorders of acid-base balance and electrolytes are seen in a high percentage of hospitalized individuals, and electrolyte disorders are frequent complications of treatment for a variety of common conditions. Renal disease is one of the major sequelae of common disorders such as diabetes and hypertension.

7. Volume of Body Fluids – 54% of the body weight – body content of fat – Age