Diagnosis of Chronic Kidney Disease
Your doctor will ask about your symptoms and medical history and perform a physical exam. He or she will also do a few tests, including the following:
Commonly Ordered Blood Tests
- Complete blood count
- Calcium, phosphorus, parathyroid hormone
Urine Protein Level
During the filtering process, the kidneys usually return protein to the circulation. With chronic kidney disease, the kidneys allow protein to leak into the urine. Different kinds of proteins can leak into the urine. Albumin is a protein that often appears in the urine of people who have chronic kidney disease caused by high blood pressure or diabetes.
Different tests can be used to check for protein in the urine.
- 24-hour urine protein—measures the amount of protein in urine produced over a 24-hour period
- Dipstick for urine protein—measures the amount of protein in a single urine sample taken first thing in the morning
- Microalbuimin screening in ]]>type 1]]> and ]]>2]]> diabetic patients
- 24-hour urine albumin—measures the amount of albumin in a sample of all urine produced in 24 hours
- Dipstick for urine albumin—measures the amount of albumin in a single urine sample
- Protein-to-creatinine ratio—compares the amount of protein to the amount of creatinine in a urine sample
- Albumin-to-creatinine ratio—compares the amount of albumin to the amount of creatinine in a urine sample
Blood Urea Nitrogen (BUN) and Creatinine Levels
Creatinine and BUN are waste products that the kidneys usually remove from the blood. When the kidneys are damaged, the creatinine and BUN levels rise in the blood. A simple blood test can measure these levels.
Estimated Glomerular Filtration Rate
The glomerular filtration rate (GFR) is a measurement of how well the kidneys are processing wastes. Your doctor can calculate the GFR based on your:
- Body size
- Blood creatinine level
The formula used in clinical practice is called the Cockcroft-Gault equation:
Creatinine clearance or GFR (mL per minute) = (140 – age) X body weight in kilogram ÷ 72 X serum creatinine. If calculating for a female, this product is multiplied by 0.85.
The GFR determines the stage of chronic renal disease.
|Stage||Glomerular Filtration Rate (GFR)|
|1||Over 90 mL/min (normal)|
|2||60 to 89 mL/min (mild decrease)|
|3||30 to 59 mL/min (moderate decrease)|
|4||15 to 29 mL/min (severe decrease)|
|5||under 15 mL/min (kidney failure or end-stage renal disease)|
Urinary Tract Ultrasound or CT Scan
Your doctor may order an ultrasound or a ]]>CT scan]]> to evaluate your kidneys, ureters, and bladder. These tests can tell your doctor if you have a kidney stone or tumor that may have caused the chronic kidney disease.
Your doctor may recommend a kidney biopsy, unless you have small kidneys or have end-stage renal disease. During a kidney biopsy, a small piece of kidney tissue is removed and examined under a microscope. The biopsy can tell how much kidney damaged has already occurred. It also may determine the cause of your kidney disease.
Your doctor may order the following tests to determine the underlying disease causing your CKD:
- Complements 3 and 4—collagen vascular disease, immune complex disease or ]]>hepatitic C]]> -related disease
- Antineutrophil cytoplasmic antibody assay—vasulitis
- Protein electophoresis—multiple myeloma
Are you at risk for chronic kidney disease? National Kidney Foundation website. Available at: http://www.kidney.org/atoz/atozItem.cfm?id=134 . Accessed July 30, 2005.
Johnson CA, Levey AS, Coresh J, Levin A, Lau J, Eknoyan G. Clinical practice guidelines for chronic kidney disease in adults: Part II. glomerular filtration rate, proteinuria, and other markers. Am Fam Phys. 2004; 70:1091-1097.
Snively CS, Gutierrez C. Chronic kidney disease: prevention and treatment of common complications. Am Fam Phys. 2004;70:1921-1930.
Last reviewed November 2008 by ]]>Adrienne Carmack, MD]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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