There are several kinds of kidney diseases, ranging from kidney stone formation, polycystic kidney disease to kidney cancer. Early diagnosis of kidney disease may reduce the risk of kidney failure in affected individuals. The doctor may choose various tests for kidney diagnosis based on age, symptoms, medical history, state of health and lifestyle. Chronic kidney disease can be diagnosed using blood tests, urine tests, imaging techniques and biopsy.
Important Tests For Kidney Diseases
Blood Creatinine Test
The creatinine test is the best measure of kidney health that analysis the glomerular filtration rate (GFR), by estimating the levels of blood creatinine. The normal levels are higher than 90ml/min, but in case of kidney disease, the results come persistently lower than 60ml/min. The test determines the extent of kidney disease and kidney malfunctioning.
Fasting Blood Glucose Test
Fasting blood glucose levels will help to determine, whether there is damage to blood vessels of the kidneys, owing to high blood sugar levels.
Blood Urea Nitrogen (BUN) Test
BUN test measures the nitrogen formed in the blood from the urea waste. Under kidney malfunctioning, urea is not efficiently removed from the blood and hence, the blood urine nitrogen levels increases to abnormal levels.
Urine ACR (albumin to creatinine ratio)
Urine ACR test detects the amount of leaked albumin into the urine, during inflamed or damaged kidney condition. During any kidney infection and damage, the albumin leaks out in micro quantities into the urine, referred as microalbuminuria. With decline of kidney function, the albumin amount increases, known as macroalbuminaria. Hence, by taking the ratio of albumin to creatinine, the stage of kidney damage can be determined.
In urinalysis, a simple dipstick is employed to analyze the presence of protein, bilirubin, glucose or ketones in the urine. These metabolites are considered as the important indicators of kidney troubles. Proteinuria (high protein in urine) is the most common sign of a kidney disease. Additionally, urinalysis also checks for alkalinity or acidity of the urine. The cellular abnormalities in the urine are observed microscopically. Urine concentration analysis is performed to check the concentrating power of the diseased kidneys and urine infection is manifested by urine culture growth.
Sound waves are utilized to create an image of the kidneys and analyze the kidney size. During ultrasound, one can easily detect abnormalities of clogged blood vessels and kidney stones, through reflected sound waves (echogenicity). Kidney ultrasound also helps to estimate the duration of chronic kidney disease and analyze any restriction present in urine flow. Ultrasound is very useful in detecting the real cause of kidney disease, like polycystic kidney disease or kidney blockage.
For renal artery stenosis (restricted blood flow) analysis, angiogram is performed to analyze the region of blockage and check the harm caused by the blockage within kidney passage.
To find the exact cause of the kidney disease, a small amount of kidney tissue is taken with help of specialized needle, under local anesthesia. Computerized tomography or ultrasound can be used to guide the inserted needle and the extracted sample is being sent for laboratory examination. Kidney biopsy helps in confirmation of the chronic kidney disease.