Acute Renal Failure is usually diagnosed using blood and urine tests to check kidney function. These tests include blood urea nitrogen (BUN), serum creatinine, complete blood count (CBC) and a urinalysis.

Blood urea nitrogen (BUN) test - This test measures the amount of nitrogen in your blood that comes from the waste product urea. A BUN test is done to estimate the functioning of kidney. The BUN level increases, if the kidneys are not able to remove urea from the blood. Heart failure, dehydration, certain medicines, intestinal bleeding can also increase the BUN level. Liver disease or damage can decrease the BUN level

Serum creatinine -This test measure the level of the waste product creatinine in the blood and urine. If the kidneys are damaged and cannot function normally, the amount of creatinine in the urine decreases while the amount of creatinine in the blood increases.

Complete blood count (CBC) - A CBC provides important information about the red blood cells, white blood cells, and platelets. It can be used to check for diseases or infections that could be causing renal failure.

Urinalysis - Urinalysis examine the sample of the urine for color, clarity, odor, concentration, and acidity. It also checks for abnormal levels of protein, sugar, and blood cells or other substances found in the urine. The presence of protein in the urine indicates kidney damage.