According to the Centers for Disease Control and Prevention, results from a 2008 national health survey show that 3.7 million American adults have renal disease. This figure does not include people who are in the hospital receiving treatment for this disorder. The CDC's statistics for 2006 list 45,344 deaths due to just three types of renal diseases. Several diagnostic tests are currently available to help detect renal problems.
Urinalysis
One of the first diagnostic tests typically used to check for renal disease is a urinalysis, according to Dr. Seyed-Ali Sadjadi, Associate Professor of Medicine at Loma Linda University School of Medicine in the "The Merck Manual for Healthcare Professionals." The urinalysis involves a check of the appearance of the urine, the specific gravity, glucose, ketones, pH, odor, protein, casts, blood cells, nitrite and leukocyte esterase. Checking the appearance of urine means checking for the yellow or amber color. It also means checking for any turbidity, meaning whether the urine is foamy or cloudy. Urine can be foamy if it contains too much protein. The specific gravity tells the physician whether the kidneys are able to concentrate urine as they should. Glucose in the urine usually means a diagnosis of diabetes mellitus, and ketones will be present if the person has diabetic ketoacidosis or is undergoing severe starvation. Urine should be within a certain pH range. Urinary tract infections from certain bacteria can raise the pH, while diabetes can lower it. Rare diseases can give urine a distinct odor. High levels of protein and substances called casts are signs of renal disease. Blood cells in the urine can be due to disease, kidney damage or a urinary tract infection. Nitrites and leukocyte esterase are also signs of a urinary tract infection.
Blood Test
Several items in a blood test that indicate renal disease. In "The Washington Manual of Medical Therapeutics," Dr. Gopa Green writes that albumin, uric acid, BUN, creatinine and electrolyte levels are all important to check. If any of these have abnormal levels, it can be due to kidney disease. Albumin is a protein. Uric acid is from the daily recycling of RNA. BUN stands for blood, urea and nitrogen. The kidneys excrete urea; it is made of nitrogen and is a waste product from the breakdown of proteins. The skeletal muscles break down a substance called creatine phosphate that they use for energy. This breakdown results in creatinine, which the kidneys should excrete. Bicarbonate, potassium, sodium, calcium, phosphate and magnesium are all called electrolytes. They are minerals that have an electric charge, and should stay within a certain range.
Imaging Tests
Dr. Green describes several imaging tests in "The Washington Manual of Medical Therapeutics." An MRI can check for any masses within the kidney. Magnetic resonance angiography checks for abnormalities in the renal blood vessels. An ultrasound can look for cysts, any blockage and check on the size of the kidneys.
References
- Centers for Disease Control and Prevention: Kidney Disease
- The Merck Manual for Healthcare Professionals: Approach to the Renal Patient
- "The Washington Manual of Medical Therapeutics"; Dr. Gopa Green, Dr. Ian Harris., Dr. Grace Lin., Dr. Kyle Moylan.; 2004
