Also Known As
Glycated Serum Protein (GSP)
Glycated Albumin
This article was last reviewed on
This article waslast modified on 18 February 2022.
At a Glance
Why Get Tested?

To help monitor your diabetes over time, especially if it is not possible to monitor using the HbA1c test; to help determine the effectiveness of changes to your diabetic treatment plan

When To Get Tested?

When you are diabetic and your doctor wants to evaluate your average blood glucose level over the last 2-3 weeks

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

No test preparation is needed.

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

The fructosamine test is a measurement of glycated protein, mainly albumin (the main protein in the blood). When glucose levels in the blood are elevated over a period of time, glucose molecules permanently combine with proteins in the blood in a process called glycation. Affected proteins include albumin, haemoglobin (the protein found inside red blood cells (RBCs)) and other serum proteins. The more glucose that is present in the blood, the greater the amount of glycated protein and haemoglobin formed. These combined molecules persist for the life of the protein or RBC and provide a record of the average amount of glucose that has been present in the blood over that time period.

RBCs live for about 120 days with glycated haemoglobin (HbA1c) representing average blood glucose levels over the past 2 to 3 months with the most recent glucose levels having the largest effect on the average value (HbA1c). Serum proteins have a shorter lifespan, about 14 to 21 days, so glycated proteins, and the fructosamine test, reflect average glucose levels over a 2 to 3 week time period.

Keeping blood glucose levels as close as possible to normal helps patients with diabetes to avoid many of the complications and progressive damage associated with elevated glucose levels such as eye disease, kidney disease or nerve damage. The effectiveness of the treatment is monitored using HbA1c or occasionally, a fructosamine test.

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Common Questions
  • How is it used?

    Both fructosamine and HbA1c tests are used primarily as monitoring tools to help people with diabetes control their blood sugar. HbA1c is most frequently used being a very reliable marker. Fructosamine may be useful in situations where HbA1c cannot be reliably measured however measurement is not standardised meaning no reference intervals can be recommended and one laboratory’s results can be compared to another. Fructosamine is also not free from problems being affected by conditions that affect circulating proteins. However the conditions fructosamine measurement may be useful include:

    • RBC loss or abnormalities – the HbA1c test will not be accurate when a patient has a condition that affects the average age of red blood cells (RBCs) present, such as haemolytic anaemia or blood loss. The presence of some haemoglobin variants may affect certain methods for measuring HbA1c. In these cases, fructosamine can be used to monitor glucose control.
    • Rapid changes in diabetes treatment – fructosamine allows the effectiveness of diet or medication adjustments to be evaluated after a couple of weeks rather than months. This is rarely undertaken however with capillary (finger prick) glucose testing being the most widely used alternative to monitor day to day control.
    • Diabetes in pregnancy – good diabetes control is essential during pregnancy, and the needs of the mother frequently change during gestation; fructosamine measurements may occasionally be requested along with glucose levels to help monitor and accommodate shifting glucose and insulin requirements. This is rarely undertaken however with capillary (finger prick) glucose testing being the gold standard.

    The fructosamine test is not used to diagnose diabetes. The World Health Organisation recommends a glucose or HbA1c blood test if diabetes is suspected.


  • When is it requested?

    Although not widely used, the fructosamine test may be of value in the above situations.

  • What does the test result mean?

    If a patient’s fructosamine is increased, then the patient’s average glucose over the last 2 to 3 weeks may have been elevated. In general, the higher the fructosamine concentration the higher the average blood glucose level. Trends may be more important than absolute values primarily due to lack of assay standardisation and wide variety of values between people (intraindividual and interindividual biological variation) reference intervals are difficult to validate. If there is a trend from a normal to high fructosamine, it may indicate that a patient’s glucose control is not adequate – that they are getting too much sugar or their treatment has become less effective. In these situations, diet and treatment plans may need to be reviewed.

    Fructosamine results must be evaluated in the context of the patient’s other clinical findings. Falsely low fructosamine results may be seen with decreased blood total protein and/or albumin levels, with conditions associated with increased protein loss, or with changes in the type of protein produced by the body. In this case, a discrepancy between the results obtained from daily glucose monitoring and fructosamine testing may be noticed. Also, someone whose glucose concentrations swing erratically from high to low may have normal or near normal fructosamine and HbA1c levels but still have a condition that requires frequent monitoring.

  • Is there anything else I should know?

    High levels of vitamin C (ascorbic acid), lipaemia and haemolysis can interfere with test results.

  • If I have diabetes, do I need to have both HbA1c and fructosamine measurement?

    No. HbA1c is used most of the time to monitor (and diagnose) diabetes. It is the best single test for establishing an estimate of longer term control. Fructosamine is rarely required and only sometimes performed in the situations described in this article.

  • Do I need to fast for a fructosamine test?

    No. Since it measures glycated protein and determines the average glucose over the past 2-3 weeks, the fructosamine test is not affected by food that you have eaten during the day. It can be measured at any time during the day.

  • Shouldn't someone with a family history of diabetes have a fructosamine test?

    No. This test is not recommended for screening people without diabetes, even if you have a strong family history.