Kidney Function

The kidney has several functions including

  1. Excretion of wastes
  2. Acid base balance
  3. Blood pressure regulation
  4. Hormone secretion
  5. Osmolality (concentration) regulation


Urologists and nephrologist our specialists who looked after kidney diseases. Nephrologist tend more towards functional aspects and do not perform surgery while urologists tend more towards anatomical problems with the kidney with an extra emphasis on functional obstruction of the urinary tract.


There many ways of assessing the different functions of the kidney. One of the primary methods of assessing the filtration function of the kidney is an indirect measure of something none as glomerular filtration rate. The glomerular is the filtration unit of the kidney. There are hundreds of thousands of these in each kidney, each one acting as a small filter for the blood. The goal is to physically separate wastes from things which the body wants to retain (such as protein).


Creatinine is a byproduct of muscle metabolism. It is not survey particular purpose and is not harmful but it is almost entirely excreted by the kidney. Its measurements in the blood can be used to indirectly measure kidney function. Increasing creatinine can be associated with decreased kidney function.


If there is concern regarding kidney function unrelated to obstruction or a structural abnormality then a nephrologist is often times consulted. A basic evaluation often times includes:


  1. Serum studies
    1. Complete blood count
    2. Electrolytes (sodium, potassium, chloride, bicarbonate, urea)
    3. Creatinine
    4. Serum proteins: Protein electrophoresis with complement C3 and complement C4
    5. Immunology studies: Nuclear antibodies and DNA double-strand antibodies
    6. Neurology: Hepatitis B surface antigen, hepatitis B surface antibody, hepatitis C antibody
  2. Urine studies
    1. Urinalysis
    2. Random urine chemistry: urine creatinine, urine protein (with protein/creatinine ratio), urine protein electrophoresis, urine microalbumin (with microalbumin/creatinine ratio)