Test Overview
A microalbumin test
checks urine for the presence of a protein called
albumin. Albumin is normally found in the blood and
filtered by the
kidneys. When the
kidneys are working properly, albumin is not present
in the urine. But when the kidneys are damaged, small amounts of albumin leak
into the urine. This condition is called microalbuminuria.
Microalbuminuria is most often caused by kidney damage from
diabetes. But many other conditions can lead to kidney
damage, such as
high blood pressure,
heart failure,
cirrhosis, or
systemic lupus erythematosus (SLE). If early kidney
damage is not treated, larger amounts of albumin and protein may leak into the
urine. This condition is called macroalbuminuria or proteinuria. When the
kidneys spill protein, it can mean serious kidney damage is present. This can
lead to
chronic kidney disease. A microalbumin urine test can
be done on a sample of urine collected randomly (usually after the first time
you urinate in the morning), a sample collected over a 24-hour period, or a
sample collected over a specific period of time, such as 4 hours or
overnight.
Why It Is Done
A microalbumin urine test is done to
check for protein (albumin) in the urine. Early detection may change treatment
in an effort to preserve as much kidney function as possible.
How To Prepare
You do not need to do anything before
having this test.
How It Is Done
For a random urine test, you will
provide a clean-catch midstream urine sample. A morning urine sample gives the
best information about microalbumin levels.
Clean-catch midstream one-time urine collection
This collection method prevents contamination of the sample.
- Wash your hands to make sure they are clean
before collecting the urine.
- If the collection cup has a lid,
remove it carefully and set it down with the inner surface up. Do not touch the
inside of the cup with your fingers.
- Clean the area around your
genitals.
- A man should pull back the foreskin, if
present, and clean the head of his penis thoroughly with medicated towelettes
or swabs.
- A woman should spread open the folds of skin around her
vagina with one hand, then use her other hand to clean
the area around her vagina and
urethra thoroughly with medicated towelettes or swabs.
She should wipe the area from front to back to avoid contaminating the urethra
with bacteria from the
anus.
- Begin urinating into the toilet or urinal. A
woman should continue to hold apart the folds of skin around the vagina while
she urinates.
- After the urine has flowed for several seconds, place
the collection cup into the stream and collect about
2 fl oz (60 mL) of this
"midstream" urine without interrupting the flow.
- Do not touch the
rim of the cup to your genital area, and do not get toilet paper, pubic hair,
stool (feces), menstrual blood, or other foreign matter in the urine
sample.
- Finish urinating into the toilet or
urinal.
- Carefully replace the lid on the cup and return it to the
lab. If you are collecting the urine at home and cannot get it to the lab in an
hour, refrigerate it.
A urine sample collected over time, such as over 4 or
24 hours, gives the most accurate results so you may be asked to collect your
urine over a specific time period.
Timed urine collection (24 hours)
- You start collecting your urine in the morning. When you first
get up, empty your bladder but do not save this urine. Write down the time that
you urinated to mark the beginning of your 24-hour collection
period.
- For the next 24 hours, collect all your urine. Your doctor
or lab will usually provide you with a large container that holds about
1 gal (4 L). The container has
a small amount of preservative in it. Urinate into a small, clean container and
then pour the urine into the large container. Do not touch the inside of either
container with your fingers.
- Keep the large container in the
refrigerator for the 24 hours.
- Empty your bladder for the final
time at or just before the end of the 24-hour period. Add this urine to the
large container and record the time.
- Do not get toilet paper, pubic
hair, stool (feces), menstrual blood, or other foreign matter in the urine
sample.
How It Feels
There is no discomfort while collecting a
urine sample.
Risks
There is no chance of problems while collecting a
urine sample.
Results
A microalbumin test checks urine for the
presence of a protein called
albumin. Microalbuminuria is most often caused by
kidney damage from
diabetes.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Higher-than-normal values
You may need more than
one test to find out how well your kidneys are working.
- If your results are higher than normal, your doctor may check
your urine more often to watch for kidney damage.
- If you have 2 or 3 high results in a 3- to 6-month period and
you have diabetes, your doctor may find kidney damage (diabetic nephropathy). Even though diabetes is the most common reason for high
results, there are many other kidney problems that can cause high
results.
Pregnant women with diabetes may have their urine checked
to watch for high amounts of albumin.
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
- Having high blood sugar levels,
urinary tract infections, high blood pressure,
heart failure, or a high fever during an
infection.
- Exercising just before the test.
- Taking
medicines, such as aspirin,
corticosteroids, or some
antibiotics, such as amoxicillin.
- Having
menstrual bleeding or vaginal discharge, which may temporarily affect the urine sample.
What To Think About
- The American Diabetes Association recommends a
microalbumin urine test for people who have:
- Type 2 diabetes: First at diagnosis, and then yearly for diabetic
nephropathy.
- Type 1 diabetes: Yearly screening for diabetic
nephropathy should begin 5 years after diagnosis.
- A blood test to check creatinine levels is often done with a microalbumin urine test. For more information, see the topic
Creatinine and Creatinine Clearance.
- A
less precise test, the urine dipstick test, can be used to check for
microalbuminuria in a single sample of urine. But the dipstick test does not
accurately detect microalbuminuria and is not recommended in place of a
microalbumin urine test.
References
Citations
- Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Saunders.
- Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
Other Works Consulted
- American Diabetes Association (2012). Standards of medical care in diabetes—2012. Diabetes Care, 35(Suppl 1): S11–S63.
- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Saunders.
- Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
- Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Credits
| By | Healthwise Staff |
|---|
| Primary Medical Reviewer | E. Gregory Thompson, MD - Internal Medicine |
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| Specialist Medical Reviewer | Michael Mallea, MD - Nephrology |
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| Last Revised | August 9, 2012 |
|---|
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Saunders.
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.