Fructosamine Test

How Is It Different Than the A1c Test?

Mature man diabetic testing himself at home
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The fructosamine test is similar to the hemoglobin A1c test, but it is not as commonly used. It indicates what your blood glucose levels have been over a length of time. The difference between the two tests is that the fructosamine test measures your average blood glucose level over the past two or three weeks, while the A1c test shows how it has been over the past two to three months.

The fructosamine test is used when your doctor wants to keep a closer eye on your blood sugar levels.

For example, if she made changes made in your medications or insulin schedule and wants to see whether they are working well. The test may also be used during pregnancy when your body is changing constantly.

The fructosamine test is a blood test, like the A1c, except that it measures glycated protein in the blood instead of glycated hemoglobin. Sugar molecules that are present in your blood stick to proteins. These proteins circulate in your bloodstream for 14 to 21 days, so measuring them gives a picture of the amount of sugar in your blood for that time period.

When is the Fructosamine Test Used?

Unlike the A1c test, the fructosamine is not used as a screening test for people who are not diabetic or who have well-controlled diabetes.

There are times when the A1c test can't provide reliable monitoring, and in these cases the American Diabetes Association says the fructosamine test may be a better choice.

 Your doctor might order a fructosamine test if you've had a recent change in your medications or insulin, so he can monitor the effectiveness of the new treatments after just a few weeks rather than waiting months to do an A1c test.

The test is also used in gestational diabetes because changes can happen very quickly during pregnancy.

The shorter time span of the test allows the doctor to track your blood glucose levels more closely.

If you have had blood loss or hemolytic anemia, the rapid turnover of your red blood cells will mean that testing the hemoglobin A1c will be falsely low, so a fructosamine test may be more accurate for you.

If you have sickle cell anemia or other hemoglobin variants, the hemoglobin A1c test is less reliable and the fructosamine test may be preferred.

How is the Fructosamine Test Done?

This is a blood test done with a sample drawn from a vein or fingerstick and analyzed in a laboratory. Fasting is not required. A home test was formerly produced but discontinued in 2002 as it wasn't accurate.

What Do the Fructosamine Test Results Mean?

The higher the fructosamine level, the higher your average blood glucose level was in the previous two to three weeks. Usually a trend is monitored with repeat tests. If the results remain high, it shows you have not had good blood glucose control. Your doctor will try to determine the cause and help you adjust your medications, diet, and other factors to maintain better control.


Fructosamine - The Test. October 30, 2015. Lab Tests Online, American Association for Clinical Chemistry. Accessed  February 10, 2016.

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