Microalbumin in clinical diagnosis

2. Microalbuminuria
Other Name: Urine Albumin and Albumin/Creatinine Ratio
WHY GET TESTED?
To detect early kidney disease in those with diabetes or other risk factors, such
as high blood pressure (hypertension)
WHEN TO GET TESTED?
Annually after a diagnosis of type 2 diabetes; annually 5 years after diagnosis of
type 1 diabetes

3. SAMPLE REQUIRED?
A random, Spot, overnight, or 24-hour urine sample
TEST PREPARATION NEEDED?
None

4. • Albumin is a major protein normally present in blood. The urine albumin test detects
and measures the amount of albumin in the urine.
• The presence of a small amount of albumin in the urine may be an early indicator of
kidney disease.
• A small amount of albumin in the urine is sometimes referred to as URINE
MICROALBUMIN OR MICROALBUMINURIA.
• "Microalbuminuria" is slowly being replaced with the term "albuminuria," which
refers to any elevation of albumin in the urine.
• Protein in the urine (proteinuria) most often occurs when either the glomeruli or tubules in the kidney
are damaged. Inflammation and/or scarring of the glomeruli can allow increasing amounts of protein
to leak into the urine. Damage to the tubules can prevent protein from being reabsorbed.
WHAT IS BEING TESTED?

5. Albumin is one of the first proteins to be detected in the urine with kidney damage.
People who have consistently detectable small amounts of albumin in their
urine (albuminuria) have an increased risk of developing progressive kidney failure and
cardiovascular disease in the future.
a. A urine albumin test is used to screen for kidney disease in people with chronic
conditions such as diabetes and high blood pressure.
b. It can detect small amounts of albumin that escape from the blood through the
kidneys into the urine several years before significant kidney damage becomes
apparent.

6. Most of the time, both albumin and creatinine are measured in a
random urine sample and an albumin/creatinine ratio (ACR) is
calculated.
This may be done to more accurately determine how much albumin
is escaping from the kidneys into the urine.
The concentration (or dilution) of urine varies throughout the day
with more or less liquid being released in addition to the body's
waste products. Thus, the concentration of albumin in the urine
may also vary.

7. Creatinine, a byproduct of muscle metabolism, is normally released into the
urine at a constant rate and its level in the urine is an indication of the urine
concentration.
This property of creatinine allows its measurement to be used to correct for
urine concentration in a random urine sample.
The American Diabetes Association has stated a preference for the ACR for
screening for albuminuria indicating early kidney disease.
Since the amount of albumin in the urine can vary considerably, an elevated
ACR should be repeated twice within 3 to 6 months to confirm the diagnosis.

8. Plasma, the liquid portion of blood, contains many different proteins, including albumin.
One of the many functions of the kidneys is to conserve plasma proteins so that they are
not released along with waste products when urine is produced.
There are two mechanisms that normally prevent protein from passing into urine:
(1) the glomeruli provide a barrier that keeps most large plasma proteins inside
the blood vessels and
(2) the smaller proteins that do get through are almost entirely reabsorbed by the
tubules.
THE TEST SAMPLE : WHAT IS BEING TESTED?

9. Albumin is a globular, water-soluble, un-
glycosylated serum protein of approximate
molecular weight of 65,000 Daltons. (10-24)
Albumin (when ionized in water at pH 7.4, as found in the body) is negatively charged. The glomerular
basement membrane is also negatively charged in the body; some studies suggest that this prevents
the filtration of albumin in the urine.
According to this theory, that charge plays a major role in the selective exclusion of albumin from the
glomerular filtrate. A defect in this property results in nephrotic syndrome leading to albumin loss in
the urine. Nephrotic syndrome patients are sometimes given albumin to replace the lost albumin.
It constitutes about half of serum protein. It is
produced in the liver.

13. • Maintains oncotic pressure (Prevents water enter in to circulatory system)
• Transports thyroid hormones & other hormones, in particular, ones that are fat-soluble
• Transports fatty acids ("free" fatty acids) to the liver and to myocytes for utilization of energy
• Transports unconjugated bilirubin
• Transports many drugs; serum albumin levels can affect the half-life of drugs
• Competitively binds calcium ions (Ca2+)
• Serum albumin, as a negative acute-phase protein, is down-regulated in inflammatory states.
As such, it is not a valid marker of nutritional status; rather, it is a marker of an inflammatory
state
• Prevents photodegradation of folic acid
FUNCTIONS

15. 800,000 to 1.5 million nephrons

19. Difference between serum/plasma albumin, prealbumin, and urine albumin
Although the names are similar, albumin and prealbumin are completely different
molecules. They are both proteins made by the liver, however, and both have been used
historically to evaluate nutritional status.
Serum/plasma (or blood) albumin is now more often used to screen for and help
diagnose liver or kidney disease and is tested on a blood sample.
The urine albumin test (also called a microalbumin test) detects and
measures albumin in the urine as an early indicator of kidney damage.

20. MOLECULAR MECHANISM BEHIND THE MICROVASCULAR DYSFUNCTION

21. Yes, if you are diabetic,
control over your blood glucose level.
Keeping high blood pressure under control is also effective in
preventing kidney damage that leads to microalbuminuria.
Some studies have shown that those who have albuminuria can
prevent it from worsening or may reverse it with good glycemic
and blood pressure control, or by quitting smoking.

22. Yes, albuminuria is not specific for diabetes. It may also be associated
with hypertension (high blood pressure), some lipid abnormalities, and several
immune disorders. Elevated results may also be caused by vigorous exercise,
blood in the urine, urinary tract infection, dehydration, and some drugs.

23. Normal Value :
50371877

24. Urine Protein Manual Machine
Nil <35 µg/dl
+ 100
++ 200
+++ 500
++++ >1000

25. X 0.85
MALE
FEMALE