Normal levels:

·         Urea:

2.5-7.8 mmol/L

 ·        BUN:

7 to 20 mg/dL

·         Uric Acid:

Adult Female: 2.4 to 6.0 mg/dL

Adult Male: 3.4 to 7.0 mg/dL

Children: 3 to 4 mg/dL

·         Creatinine:

Adult males: 0.6 to 1.2 mg/dL

Adult females: 0.5 to 1.1 mg/dL

·         BUN/Creatinine Ratio:

          12:1 to 20:1

Increased levels of each of these parameters can indicate a number of conditions and not necessarily health disorders. For example, increased creatinine levels can occur due to heavy exercise, consumption of cooked meat, or taking protein supplements apart from kidney diseases. Thus, these parameters are interpreted in combination and further tests are performed to confirm health disorders.

The kidneys are a pair of bean-shaped organs located on either side of the spinal column in the abdomen towards the back. The kidneys perform a number of important functions. The most important of these is that they filter the blood of waste products generated out of regular metabolic activities of the body, primarily urea, and excretes them out of the body through urine. They help in maintaining the normal pH and water balance of the body. The kidneys also play essential roles in the synthesis of Vitamin D and Red Blood Cells (RBCs).

The Kidney Function Test includes the following tests to monitor kidney function:

·        Blood Urea Nitrogen (BUN)/ Urea:

Blood Urea Nitrogen is a test to measure the amount of urea nitrogen present in the blood. Urea is a nitrogenous by-product of the metabolism of protein and its level in blood serves as an indication of the amount of nitrogen present in blood as urea. In simpler terms, BUN is the measure of the amount of nitrogen present in blood as urea. High BUN levels in the blood can be caused by kidney diseases, dehydration, and obstruction in the urinary tract due to kidney stones, prostate gland enlargement etc.

Urea test measures the level of Urea in blood. Urea is a final waste product formed from the breakdown of proteins. Urea is filtered out of the blood by the kidneys to excrete excess nitrogen present in blood through urine. Excess urea in blood is called uremia and can be caused by a number of conditions including kidney diseases.

·         Uric Acid:

This test measures the level of Uric acid in the blood. Uric acid is a waste product formed from the breakdown of purines, which are essential building blocks of DNA. It is also produced by the metabolism of proteinaceous food, especially red meat. Uric acid is excreted by the kidneys through urine and a small portion through stool. The uric acid test indicates the level of uric acid in the blood and serves as an indirect estimation of kidney function.

The excess uric acid in the blood is called hyperuricemia and causes gout due to the accumulation of uric acid crystals in the synovial fluid between joints. Hyperuricemia also causes the formation of hard lumps of uric acid crystals called tophi under the skin and at the top of the ears. Uric acid crystals can also accumulate in the kidneys and cause kidney stones.

·         Creatinine:

This test measures the level of Creatinine in blood. Creatinine is a waste product formed from the normal breakdown of muscles in the body. Creatinine is almost completely excreted by the kidneys, so their levels in blood serve as an indication of kidney function.

Excess creatinine in the blood can be found due to decreased elimination from the kidneys as well as due to increased creatinine production by muscular breakdown, eating cooked meat, protein supplements, etc.

·         BUN/Creatinine Ratio:

BUN/Creatinine Ratio compares the levels of nitrogen as urea in blood to the levels of creatinine in the blood. This ratio serves as a more accurate representation of kidney function. It is also used to check for dehydration since the BUN level increases in dehydration while creatinine levels remain the same. Low BUN to creatinine ratio can be caused by a low protein diet, liver cirrhosis, rhabdomyolysis (muscle disease), Syndrome of inappropriate antidiuretic hormone secretion (SIADH) as well as during pregnancy.

This test is performed on a blood sample. A syringe with a fine needle attached is used to withdraw blood sample from a blood vessel in your arm generally from the inner side of the elbow area. The doctor, nurse or the phlebotomist will tie an elastic band around your arm which will help the blood vessels to swell with blood and hence makes it easier to withdraw blood. You may be asked to tightly clench your fist. Once the veins are clearly visible, the area is cleaned with an antiseptic solution and then the needle is inserted into the blood vessel to collect the sample. You may feel a tiny pinprick during the procedure. Blood sample once collected is then sent to the laboratory.

There is no risk associated with the test. However, as this test involves a needle prick to withdraw the blood sample, rarely, a patient may experience increased bleeding, hematoma (blood collection under the skin) formation, bruising or infection at the site of needle prick.

A fasting period of 8 to 12 hours is prescribed before the test is performed. Inform the doctor of any medications you may be taking. No other specific preparations are usually required before the Kidney Function Test.

Additional tests that may be prescribed in case of abnormal Kidney Function test result are: Blood Electrolyte Tests Urine Creatinine Test Estimated Glomerular Filtration Rate (eGFR) Test Creatinine Clearance Test Urinalysis Blood Sugar Tests Urine Albumin Test Kidney Biopsy Imaging Tests

Chronic Kidney Disease (CKD) or Chronic Kidney Failure is a medical condition characterized by steadily progressive loss of kidney function leading to complete kidney failure if left untreated. The kidneys filter out metabolic wastes out of the blood for excretion, and their progressive loss of function due to CKD causes these wastes to build up in the body to toxic levels and may turn fatal in end stage kidney failure. CKD may be caused by conditions that affect kidney function, including: Diabetes Type 1 and 2 Hypertension (high blood pressure) Glomerulonephritis (inflammation of the filtering units of the kidneys called glomeruli) Interstitial nephritis (inflammation of the tubules of the kidneys) Polycystic kidney disease (formation of cysts in the kidneys) Urinary tract blockage due to kidney stones, prostate gland enlargement, or some cancers Vesicoureteral reflux (backward flow of urine into the kidneys) Pyelonephritis (general kidney infection)nSymptoms of CKD are not easily apparent in the early stages. They build up in number and intensity with disease progression, usually only when significant damage has already occurred.

Common signs and symptoms of kidney diseases include: Swelling of the lower limbs, ankles, thighs Puffiness around the face and eyes or in the wrists and stomach Frothy or dark coloured urine Blood in urine Reduced urine volume Burning sensation during urination Change in frequency of urination Pain in the mid back region below the ribs at the location of the kidneys

Common risk factors that may lead to development of kidney diseases include: Diabetes Hypertension (high blood pressure) Heart and cardiovascular diseases Family history of kidney diseases