Unless the kidneys are swollen or there's a tumour, your doctor can't usually check for disease by feeling the kidneys. Instead, your doctor might test the urine and blood, take a scan of the kidneys, and test samples of kidney tissue. A routine urine test, called a urinalysis, checks for protein, sugar, blood, and ketones (created when the body breaks down fat). The urine tested with a dipstick, which is a thin piece of plastic covered with chemicals that react when they touch substances in the urine. Your doctor will also check for red and white blood cells in the urine during a urinalysis (the urine is examined under a microscope). Depending on the suspected cause of the kidney problem, other tests may also be done.