A 24-hour urine test is used to evaluate kidney function, states Johns Hopkins Medicine. Urine collected over a 24-hour period is tested for specific waste products to determine whether or not they are present within normal quantity ranges. A doctor can make or confirm diagnoses based upon the test results.
High levels of urea in urine indicate disease that compromises the functions of the kidneys, according to MedicineNet.com. Urea, a nitrogen compound formed from protein breakdown, is a normal waste product present in urine. Creatinine is another normal waste molecule formed from creatine during muscle tissue breakdown. It is filtered from the blood by the kidneys, and high levels of creatinine in urine also points to kidney disease or dysfunction.
Proteinuria is a condition in which higher than normal levels of protein are found in the urine, as determined by a 24-hour urine test. It is a sign of kidney damage or disease, reports Healthline. A test of urine protein levels helps to detect glomerulonephritis, an inflammation of the glomeruli, which are tiny filters in the kidney that help remove waste products, according to Mayo Clinic. The 24-hour urine protein test may also be administered when signs are present of other conditions that affect the kidneys, such as diabetes, high blood pressure, lupus, and urinary tract infection.