There are a wide range of kidney problems that can result in permanent damage to the kidney filtration units or kidney tissue. Many of these signs can only be identified by a physician, but they are often accompanied by symptoms that are noticeable to patients. Once these signs have been identified, further testing can be done to determine the severity of the kidney damage and develop a course of treatment.
Microalbuminuria
When the filtering structures of the kidneys become damaged, a protein produced in the liver leaks into the urine. This protein is called albumin and the leak of albumin into the urine is known as microalbuminuria. While microalbuminuria can be caused by diabetes, high blood pressure and some immune diseases, the National Institutes of Health indicates that this condition can be one of the earliest signs of kidney disease.
Proteinuria
As kidney problems progress, the filtering structures become more damaged and allow large protein molecules to leak into the urine. This condition is known as proteinuria. While protein in the urine can indicate high levels of meat consumption or other medical conditions, it is one of the most reliable signs of kidney problems. Proteinuria may be accompanied by foamy urine and swelling of the hands, face, abdomen and feet.
Decreased GFR
The National Institutes of Health defines glomerular filtration rate as how much blood is filtered through the filtering units of the kidneys per minute. When kidney damage has occurred, the glomerular filtration rate (GFR) may be decreased. Kidney disease staging is based on this measurement. According to the Temple University Kidney Transplant Program, a GFR value of 90 or above is normal. Kidney failure is diagnosed when the GFR has dropped to below 15.
Increased BUN
When protein is broken down by the body, urea nitrogen is formed. An increased level of blood urea nitrogen (BUN) can be a sign of kidney problems because impaired kidneys are unable to filter the blood adequately. Someone with an abnormally high BUN level may experience fatigue, foamy urine, lack of concentration, difficulty sleeping, swelling in the eyes, face and ankles, and decreased urine production.
Increased Creatinine
Creatinine is a waste product of creatine metabolism. In people with normal kidney function, creatinine levels should be within standard laboratory references ranges. In people with kidney damage, waste products cannot be filtered efficiently, resulting in high creatinine levels. According to the American Association for Clinical Chemistry, high creatinine levels can be caused by kidney infections, kidney stones, damage of the kidney blood vessels and reduced blood flow to the kidneys.
Reduced Creatinine Clearance
Creatinine clearance is a laboratory value that helps physicians determine how well the kidneys are able to filter small particules out of the blood. Reduced creatinine clearance can indicate chronic kidney disease, reduced kidney function or decreased blood flow to one or both kidneys. This value can be determined by taking a blood or urine sample from someone who has exhibited other signs and symptoms of kidney problems.
