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Kidney Diseases

High Microalbumin/Creatinine level

10/27/2010

Question:

My wife recently had a urinalysis done for our life insurance and we just got the results back today. We are rather concerned with what it says.

The results of the urinalysis (expected result in parenthesis): URN Total Protein - 22.0 (0.0-14.9 mg/dL) Microalbumin/Creatinine - 118.51 (0.00-21.00 mg/gCREA) URN Protein/Creatinine - 0.20 (0.00-0.20 g/gCREA) URN Microalbumin - 12.8 (0.0-3.0 mg/dL) URN Red Blood Count - 23 (0-4 HPF)

She was born with only one functional kidney. On her right side she has a megaureter and a shriveled kidney, on her left side is an enlarged kidney that handles all of her kidney functions.

We are concerned about whether this could be an onset of kidney failure or if it could be related to her shriveled kidney. What should our next step be?

Answer:

It is not possible to tell which kidney is causing the abnormal urine results.  If the right kidney has any function at all, it would be expected to be leaking protein and maybe some red blood cells.  However, sometimes the enlarged kidney that is doing all the work can be damaged by the overwork ("hyperfiltration," as it's called).

The two important tests here are:

1) The microalbumin/creatinine of 118 (which should be less than 21) -- this very sensitive test can detect a tiny amount of protein in the urine, often too small to be detected by standard methods.  This is often the very first sign of kidney damage from any of a number of causes.   

2) the urine protein/creatinine of 0.2 (which should be less than 0.2).  The higher the value, the more protein leakage is occurring.  In extreme cases, this number can be as large as 15.

So what your wife's tests tell us is that a small amount of protein is leaking from either her bad or her good kidney.  The more important question here is: how is her kidney functioning in its job of excreting waste products?   This is determined by blood tests called the blood urea nitrogen (or BUN) and the creatinine.  If either of these is elevated above normal, the kidneys' waste-excreting function is decreased below normal.

Please see the link to the article called "Kidney Tests," which explains more in detail about the urine and blood tests that can be used to estimate the amount of kidney damage.  (Be aware that the urine protein/creatinine ratio in the article, under "Urine Protein Determination," uses different units than the test your wife has had: hers would correspond to a 200 in the article.)

It would be wise for your wife to be followed by at least an internist, if not a nephrologist (kidney specialist).  She should have blood and urine tests at least once a year to follow her kidney function and to detect early signs of damage, if any occur.  

If you have more questions, or if I have not explained the above clearly enough, please feel free to write again. 

Related Resources:

Kidney Tests

For more information:

Go to the Kidney Diseases health topic, where you can:

Response by:

Mildred   Lam, MD Mildred Lam, MD
Associate Professor of Medicine
School of Medicine
Case Western Reserve University