| Urine Testing
Microalbumin Testing
Creatinine Clearance
Ketones
Protein
Kidney
Disease Statistics
The following disease statistics demonstrate the need for major improvements
in detecting kidney dysfunction early enough to prevent kidney disease from
occurring:
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Diabetes is the leading cause of end-stage renal disease (ESRD) in the
U.S. and Europe, accounting for 40% of new cases.
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Diabetic nephropathy accounts for about one-third of all cases of ESRD.
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According to the ADA, 20%-30% (some experts say as high as 40%) of
individuals with diabetes develop nephropathy (3.2-6.4 million people).
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Treatment for ESRD in the U.S. costs more than $2 billion annually for
diabetes patients alone. 1
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6% to 40% of people with diabetes have microalbuminuria. 80% of those
people will develop diabetic nephropathy. 2
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36% of diabetes patients who develop nephropathy enter end-stage renal
dialysis. 2
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The 5-year life expectancy in patients with diabetes-related ESRD is less
than 20%. 1
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In the U.S. in 1995 almost 100,000 people with diabetes underwent dialysis
or kidney transplantation. (Clinical Practice Recommendations. Diabetes
Care. 2000;23(suppl 1):S69-S72.)
Microalbumin Testing
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The American Diabetes Association (ADA) and the American Kidney Foundation
(AKF) recommend annual microalbumin testing.
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Studies have shown that only 10% - 20% of patients (with diabetes in the
U.S.) are tested for microalbuminuria.
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By the time symptoms occur, the kidneys may already have lost up to 80% of
their function.
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Microalbuminuria has also been shown to be associated with increased
cardiovascular disease. 2 (Has also been shown to be predictive
of retinopathy and neuropathy in NIDDM. 2
A creatinine clearance test measures the rate at which the
kidneys clear creatinine from the blood. Creatinine is a substance that is
easily excreted by the kidney in healthy people. Because all the creatinine
filtered by the kidneys in a given time interval is excreted into the urine,
creatinine levels are equivalent to the glomerular filtration rate (GFR);
the rate at which the kidneys process blood through the glomerular system.
A creatinine clearance test compares the serum creatinine
with the amount of creatinine excreted in a volume of urine for a specified
time. A 24-hour time frame is most common. At the beginning of the test, the
patient empties his bladder and the urine is discarded. Then, all urine
voided during the specific time period is collected. Sometime during the
test period a blood sample is drawn to determine the serum creatinine, so
that the amount excreted in the urine and the amount remaining in the blood
can be compared. The nurse has an important role in instructing the patient
about the purpose of the test and the procedures that will be used.
Reference creatinine clearance values
(expressed as number of milliliters per minute per 1.72 meters squared of
body surface)
- Adult males: 95 - 135 ml/min
- Adult females: 85 - 125 ml/min
- Pregnancy: may be as high as 150 - 200 ml/min
- Elderly: values diminish with age even if no renal
disease exists, as the GRF declines about 10% per decade after age 50
Decreased creatinine clearance
A decrease in the kidney's ability to clear creatinine is
an indication of decreased glomerular function.
The creatinine clearance test is used to diagnose renal
dysfunction and is also used to evaluate the progression of renal disease. A
minimum creatinine clearance of 10ml/min is necessary to maintain life
without the use of renal or peritoneal dialysis.
Ketones
What is it?: A urine test that uses a reagent strip to check for
the presence of ketones.
Ketones
spill into the urine when the body metabolizes, or breaks down, fat for fuel
in the absence of glucose. They are often identifiable by their fruity
odor.
Why is it performed?: To check for ketoacidosis (diabetic
coma). This test may also be performed as part of a routine urinalysis.
How frequently should it be done?: Frequently if you are sick
or if your blood sugar is unusually high.
What is the "normal" range for results?: No or few ketones. Some
ketones may be present after a short period of fasting. However, unless
ketones are accompanied by high blood sugar levels, they usually don't pose
a risk of ketoacidosis.
What do abnormal results mean?: The possibility of impending
ketoacidosis. If a moderate or high amount of ketones are present and blood
sugar is high, seek medical help immediately.
Protein
Also known as: Proteinuria test, or "dipstick" test.
What is it?: A test that detects protein in the urine. Healthy
kidneys filter and absorb proteins; damaged or diseased kidneys are unable
to properly process proteins and instead excrete them into the urine.
Why is it performed?: To check for renal, or kidney disease.
This test may also be performed as part of a routine urinalysis.
How frequently should it be done?: At diagnosis of diabetes, and
at least annually during follow up visits. It may be performed more
frequently with those patients at risk for renal disease.
What is the "normal" range for results?: Up to 150 mg of protein
excreted in a 24 hour period.
What do abnormal results mean?: Moderate levels of protein (.5
to 4 g/24 hours) are often present in renal disease as a complication of
diabetes. High levels (over 4 g/24 hours) occur in nephrotic syndrome.
Proteinuria can also signal other urinary tract disorders.
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