If your doctor suspects acute renal failure, he or she will use your medical history and a physical exam to help find out the cause. This will include a review of your health history and hospital chart (if you are currently hospitalized). Your doctor will look for:

• A history of other medical conditions that increase your risk for acute renal failure, such as diabetes, high blood pressure, chronic renal insufficiency, heart failure, or liver disease.
• Other recent problems or serious conditions, such as a strep throat or other serious infection, a recent blood transfusion, an enlarged prostate (benign prostatic hyperplasia), kidney stones, certain forms of cancer, or a spinal cord injury.
• Recent surgeries, X-rays, or angiography procedures that use intravenous dye. Some dyes can damage the kidneys and lead to renal failure.
• Records of any prescription or nonprescription medicines you are taking. This is especially important if you are hospitalized, because many medicines commonly used in hospitals, such as aminoglycoside antibiotics, can damage the kidneys and lead to renal failure. Other problem medicines include nonsteroidal anti-inflammatory drugs such as aspirin, ibuprofen, and ketoprofen.
• Recent weight gain or loss. Weight gain from fluid retention may be caused by heart failure or by reduced urine output. Sudden weight loss may be a sign of dehydration.
• Fluid intake and output. Reduced urine output (oliguria) occurs in about half of the people who have acute renal failure.
• Changes in blood pressure. A sudden and prolonged decrease in blood pressure is a common cause of acute renal failure, because it reduces blood flow to the kidneys. Very high blood pressure (hypertensive crisis) also may cause acute renal failure. New increases in blood pressure may result from abnormal fluid buildup in the body (volume overload).
• Problems with heart (cardiac) and lung (respiratory) function.
• Abdominal (belly), pelvic, and rectal problems.
• Skin conditions. Symptoms such as a rash, bruising, blue fingertips or toes, or swelling in the arms, legs, and face may be signs of the degree of fluid buildup and may suggest possible causes of acute renal failure.
• Other symptoms. For example, damage to the kidneys or a blockage in the urinary tract may cause pain in the sides and lower back (flank pain). Joint pain and swelling also may suggest the presence of an undiagnosed disease, such as lupus, that could be causing acute renal failure.