Kidneys are one of the most vital organs of the body responsible for filtering blood, removing waste, controlling the balance of fluids in the body and maintaining the level of electrolytes. These bean-shaped organs are the size of a large fist and are located on the side of the spine below the ribs, behind the stomach and carry some of the most important functions of the body. For filtering blood, the kidneys function to remove the waste, salt, excess water, and minerals. This filtered blood is then circulated in the body, while the waste is converted to urine and removed from the body.

This filtration process of the kidneys is carried out by million tiny filters known as nephrons. When the filtration process is hampered due to several factors, the kidneys start to send out symptoms signalling kidney problems. Though even if 90 % of the kidneys are damaged and only 10% are carrying out the filtration process, there could not be symptoms or problems; however, if there is no blood flowing to the kidney at all, a part of or the entire kidney could be damaged. Hence, it is very important to know if your kidneys are functioning effectively because kidney problems detected early on can be treated but if these diseases progress ahead, treatment options narrow and also become less effective.

The best way to know the working efficiency of your kidneys is to get regular health check-ups done from your doctor.

Some of the tests are useful to detect kidney problems and the level of kidney functioning are: 

Blood Tests

Blood tests are a great way to know if your kidneys are doing the filtration properly, removing waste effectively and are not leaking abnormal amounts of protein. Some of the components that must be included in a blood test are:

  • Serum Creatinine: The normal wear and tear on body muscles produce a waste material called creatinine which is a very important indicator of kidney health. It reflects the filtering efficiency of the kidneys since it is excreted by the kidneys at a constant rate to keep the blood level of the body low and consistent. The level of creatinine varies from person-to-person depending on age, sex, body size and muscle mass. Averagely for men creatinine levels should be between 0.6 and 1.2 mg/dl and for women it should be between 0.5 and 1.1 mg/dl. Any variations indicate abnormal functioning of the kidneys especially if the values are on the higher side; it is an early indication of kidney problems. That said, creatinine levels tend to rise with the advancement of kidney problems.
  • Glomerular Filtration Rate (GFR): Kidneys contain small filters called glomeruli that help to remove waste and excess fluid from the blood. A GFR test very accurately indicates the amount of blood that passes through the filters every minute though it is a slightly complicated test to measure. The rate of filtration is estimated based on information such as creatinine level, age, weight, height, gender, and race. The normal level of GFR is 90 or more, a GFR level of 60 or below indicates a kidney problem whereas a GFR lower than 15 is a sign of chronic kidney problem or failure.
  • Blood Urea Nitrogen (BUN): Urea nitrogen is a compound that results from the breakdown of protein in taken through food. A normal BUN level should be between 7 and 20, a variation indicates kidney problem, higher the BUN level, the lower the functioning of kidneys. 

Imaging Tests

Several imaging tests can also be used to diagnose the condition of the kidneys.

  • Ultrasound: In this test, high-frequency sound waves are used to provide images of the kidneys that help detect abnormalities in kidney size, position or obstructions such as stones, tumours, etc.
  • CT scan: CT scan or a computerized tomography scan uses computers and X-ray machines to provide in-depth, cross-sectional images of the kidney to detect abnormalities and obstructions. 

Kidney Biopsy

In this, a small piece of the kidney tissue is evaluated with a microscope to identify various conditions such as:

  • Hematuria: Blood in urine
  • Albuminuria: Excessive protein in the urine
  • Changes in kidney function

A biopsy also detects inflammation, scarring, infection, etc, in the kidney. Moreover, it can provide insights into the advancement of chronic kidney diseases and reasons for a kidney transplantation failure. 

Urine Tests

Different urine tests can indicate the efficiency of kidney functioning very accurately. These tests could involve collecting some urine while others could involve collecting urine produce of the entire 24-hour period. More specifically, urine tests indicate the amount of protein leaked through the urine from the body. Some urine tests used to check the functioning of kidneys are:

  • Urinalysis: This test evaluates the appearance, concentration, and content of urine to detect any urinary tract infections, kidney diseases, as well as health conditions such as diabetes. This test involves microscopic analysis of urine plus a dipstick test. A variation in the colour of stick when dipped in the urine sample indicates abnormalities in urine such as excess protein, blood, pus, bacteria or sugar.
  • Urine Protein: A urine protein test determines the amount of protein present in the urine. Normally, a healthy person does not have a large amount of protein in urine; however, a large amount of protein in urine is indicative of abnormalities and inefficiencies in kidney functioning. Microalbuminuria: This test measures the amount of albumin – a protein used for cell growth and tissue repair – in the urine. The presence of albumin in urine indicates a problem with kidney functioning since albumin is a protein that healthy kidneys sustain in the blood and do not filter along with the waste. Kidney problems may result in amounts of albumin being present in urine.
  • Creatinine Clearance: This is a test to determine how well the kidneys are cleaning the blood in the body; this can be measured through blood or urine samples and indicates healthy or unhealthy kidney functioning depending on the values.

In all, one or more of these tests can be used to determine the health of kidneys and their working efficiency. One must schedule regular kidney check-ups to maintain good kidney health and consult the doctor regarding your condition, in case a discrepancy in normal levels is detected.