During the diagnosis of acute renal failure, the doctor will examine your medical record and conduct a physical examination. The doctor will also examine your inpatient card (if you are currently on admission), check which regular medications you are taking, and ask you to tell about other possible health problems. A full inspection is carried out for the following purposes:
- Find out the cause of renal failure. This is an extremely important part of the diagnosis. Finding out the cause of the disease can be difficult and requires numerous tests.
- Determine the appropriate treatments for your condition. When choosing treatment methods and assessing chances for recovery, the cause of acute renal failure is usually taken into account.
- Assess the degree of efficiency of the kidneys.
- Identify and cure all possible complications.
Laboratory research
In acute renal failure, blood and urine are usually analyzed. These tests help to determine the level of waste products accumulated in the blood, the level of chemical imbalance in the body, and also allow you to identify other diseases or infections.
Clinical blood and urine tests:
- Creatinine serum. An increased amount of creatinine in the blood (serum creatinine) is usually the primary sign of acute renal failure. Multiple creatinine blood tests can help monitor the unfolding of the clinical picture of renal failure and determine the prospects for treatment. If the cause of the disease is a decrease in blood flow to the kidneys (prerenal acute renal failure), after restoration of the supply of the kidneys with the necessary amount of blood or fluid, the level of creatinine in the blood will soon return to normal.
- Blood urea nitrogen (BUN). AMK measures the level of nitrogen in the blood, which is produced from the product of vital activity – urea. Elevated levels of BUN indicate a deterioration in the ability of the kidneys to remove to be able to from the blood.
- A test for determining the level of electrolytes in the blood, such as calcium, phosphate (phosphorus), potassium and sodium.
- Clinical blood test. A blood test can determine the characteristics of red blood cells, lymphocytes and platelets. With it, you can identify diseases or infections that could cause renal failure.
- Other types of blood tests, including the test for erythrocyte sedimentation rate (ESR) and the test for antinuclear factor (ANF). These tests can be used to detect infections, autoimmune diseases, and other possible pathologies if your medical records and symptoms indicate the possible presence of a particular condition.
- Analysis of urine samples. As a result of the study, it is possible to obtain information on the presence of precipitation in the urine, which allows to determine the level of kidney damage (renal acute renal failure). This analysis also reveals:
– The level of eosinophils in the urine (type of white blood cells). The presence of eosinophils in the urine may indicate an allergic reaction as a cause of impaired renal function. An allergic reaction can often be caused by the action of a drug.
– The study of the fractional excretion of sodium in the urine. This test assesses the ability of the kidneys to process sodium based on sodium and serum levels in urine and blood. The test makes it possible to distinguish prerenal acute renal failure, which is not characterized by destruction of the kidneys, from renal acute renal failure caused by impaired renal function.
– 24-hour urine test. Urine is collected within a day. A catheter will be inserted into your bladder to collect all the urine excreted during the day. In acute renal failure, depending on your condition, the amount of urine excreted may be reduced. A thorough analysis of urine collected for a certain time also allows you to control the water balance in the body of a person suffering from renal failure.
Visual diagnostic methods
Methods of visual diagnostics make it possible to obtain an image of the kidneys. Using these tests, the doctor can determine whether renal failure is acute or chronic, and also to identify blockage in the urinary tract. For these purposes, the following visual diagnostic methods are mainly used:
- Ultrasound examination of the abdominal cavity.
- Computed tomography (CT).
- X-ray of the abdominal organs or spiral CT scan, which helps to detect kidney stones.
If acute renal failure was suspected to be caused by blockage (postrenal acute renal failure), you may need extensive research using numerous tests to identify the area and cause of the blockage. The study may include in addition to the above tests, the following:
- Retrograde pyelography. During this procedure, the doctor inserts a thin, illuminated tube (cytoscope) into your urethra. Then a catheter is inserted through the cytoscope into the ureter. A dye is injected through the catheter and radiographic images are obtained.
- Magnetic resonance imaging (MRI). With this type of MRI, your abdomen will be surrounded by a strong magnetic field. MRI can detect changes in the structure of the kidneys and urinary tract.
- Scanning of the kidneys (scintigraphic examination of the kidneys). Renal scans can assess the degree of blood supply to the kidneys, as well as the presence of blockage.