Albumin Urine Test
To check urine for the presence of the protein (albumin)
Albumin in the blood is filtered by the kidneys. When the kidneys function properly, albumin is not found in urine. However when the kidneys are damaged, small amounts of albumin leak into the urine. It is called albuminuria 蛋白尿.
Albuminuria is frequently caused by kidney damage from diabetes. But many other conditions can also lead to kidney damage, such as cirrhosis, heart failure, high blood pressure or systemic lupus erythematosus 系統性紅斑狼瘡 (SLE). If early kidney damage is not treated, larger amounts of albumin may leak into the urine. This can lead to chronic kidney disease.
An albumin 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.
For a random urine test, a clean-catch midstream urine sample is required. A morning urine sample gives the best information about albumin levels.
The normal values listed below — a reference range — just as a guide. These ranges differ from lab to lab. Your lab report should contain the range used by the lab. Also, your doctor will evaluate the 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.
Test result – Higher-than-normal values
You may need more than one test to find out how your kidneys are working.
If having 2 or 3 high results in a 3- to 6-month period you have diabetes. Your doctor may find kidney damage (diabetic nephropathy 糖尿病性腎病). Even though diabetes is the most common reason for high results, there are many other kidney problems that can cause high results.
Following conditions may affect the test result;
- 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.
The American Diabetes Association recommends three tests to check for kidney damage. They are urine albumin, blood pressure and a creatinine blood test to calculate an estimated glomerular filtration rate 腎小球濾過率估計 (eGFR). Creatinine 肌酐 is a waste product that is filtered out of the blood by healthy kidneys.
Testing Urine for Protein and Glucose