Fructosamine

2 to 3-week blood sugar average

Fructosamine forms when sugar in the blood attaches to proteins, mainly albumin. Because these proteins last about two to three weeks, the fructosamine level reflects your average blood sugar over that period. It gives your doctor a shorter-term view than HbA1c, which reflects roughly the last two to three months.

• When HbA1c may be unreliable, for example with some anaemias, recent blood loss, thalassaemia or unusual haemoglobin types
• To follow blood sugar control over a shorter period than HbA1c allows
• To see the effect of a recent change in diabetes treatment
• When a quicker picture of control is needed, such as in pregnancy with diabetes

You do not need to fast, and a meal before the test makes little difference to the result. Keep taking your diabetes and other medicines as usual unless your doctor tells you otherwise. Tell your doctor about any vitamin C supplements, as they can interfere with some fructosamine methods.

Sample

Blood sample

How it works

A trained collector takes a small blood sample from a vein in your arm at home, at any time of day that suits you. It takes a few minutes.

Report

Within 2 days of collection.

The result is compared with the laboratory's range. A higher fructosamine means blood sugar has been higher on average over the past few weeks, and a falling level suggests control is improving. Because it depends on blood protein levels, conditions that lower albumin, such as some kidney or liver diseases, can make the result misleadingly low. Your doctor will interpret it with your home glucose readings and other tests.

One test: Fructosamine, from one blood sample.