Testing the Kidneys

T A Varkey

Kidney problems do not develop overnight. The kidney function naturally starts declining after a person cross 30s. And whether you will develop a kidney problem later in life is largely dependent on your lifestyle habits and diet. In most cases, kidney problems are caused as a result of a primary condition like diabetes, hypertension or high cholesterol levels. Here are some kidney function tests that can determine whether you are at a risk of kidney disease.

Blood pressure: Kidneys perform the function of filtering blood under pressure to eliminate waste products through the urine. If your blood pressure is higher than normal it will increase the load on your kidneys and may lead to kidney disease. Alternatively, a person is suffering from kidney disease is also likely to have high blood pressure.

Blood creatinine test: Creatinine is a waste product that is produced by your muscles. It enters the bloodstream and is filtered by the kidneys to get excreted through the urine. A blood creatinine test will measure the amount of creatinine in your blood. A higher level (greater than 0.8-1.2 mg/dl in men and 0.6-0.9 mg/dl in women) may indicate that the kidneys are not functioning properly.

Blood urea test: Urea is a waste product filtered by the kidneys and excreted through the urine. It is produced by breakdown of proteins. A high level of urea in the blood (greater than 20-40 mg/dL) may indicate altered kidneys function.

Urinalysis: It is one of the recommended kidney function tests by the National Kidney Foundation (NKF). It is used to detect the presence of protein and blood cells (RBCs and WBCs) in the urine. Increased levels of both protein and blood cells indicate early signs of kidney disease.

Urea clearance test: This test is based on a comparison between the amount of urea in the blood and the amount of urea in urine. If the urea clearance is lower than the normal range (64-99 ml/min), it may indicate that the kidneys are not working properly.

Creatinine clearance test: A creatinine clearance test also compares the level of creatinine in blood with creatinine in urine to determine the rate at which the kidneys are filtering creatinine. Altered creatinine clearance range (normal range: 85-125 ml/min in men and 75-115 ml/min in women) indicates altered kidney function.

eGFR (estimated glomerular filtration rate): Glomerular filtration rate is the rate at which your kidneys filter waste products from the blood. eGFR is a value that is derived from a formula based on the amount of blood creatinine, age and gender of the person. According to the NKF, eGFR is the best estimate of determining accurate kidney function. Normal eGFR results range from 90-120 mL/min/1.73 m2.

Renal ultrasound test: Renal ultrasound is an imaging test that uses high frequency ultrasonic waves to check the shape and size of the kidneys. It can detect the flow of blood to the kidneys as well as the presence of tumors, cysts and infection around the kidneys. It also helps to detect presence of kidney stones and external damage or injury to the kidneys

Because the symptoms of kidney diseases are not evident unless the kidneys are deteriorated to a great extent , one should regularly screen your kidney function (especially if suffering from heart disease and diabetes).