Patient Test Information


  • Why Get Tested?

    To help monitor your blood glucose (sugar) levels over time if you have diabetes, especially if it is not possible to monitor your diabetes using the hemoglobin A1c test; to help determine the effectiveness of changes to your diabetic treatment plan that might include changes in diet, exercise or medications, especially if they were made recently

    When To Get Tested?

    When you have diabetes and your healthcare practitioner wants to evaluate your average blood glucose level over the last 2-3 weeks

    Sample Required?

    A blood sample drawn from a vein or sometimes from a fingerstick

    Test Preparation Needed?


  • What is being tested?

    Fructosamine is a compound that is formed when glucose combines with protein. This test measures the total amount of fructosamine (glycated protein) in the blood.

    Glucose molecules will permanently combine with proteins in the blood in a process called glycation. These proteins include albumin, the principal protein in the fluid portion of blood (serum), as well as other serum proteins and hemoglobin, the major protein found inside red blood cells (RBCs). The more glucose that is present in the blood, the greater the amount of glycated proteins that are formed. These combined molecules persist for as long as the protein or RBC is present in the blood and provide a record of the average amount of glucose that has been present in the blood over that time period.

    Since the lifespan of RBCs is about 120 days, glycated hemoglobin (hemoglobin A1c) represents a measurement of the average blood glucose level over the past 2 to 3 months. Serum proteins are present in the blood for a shorter time, about 14 to 21 days, so glycated proteins, and the fructosamine test, reflect average glucose levels over 2 to 3 weeks.

    Keeping blood glucose levels as close as possible to normal helps individuals with diabetes to avoid many of the complications and progressive damage associated with elevated glucose levels. Good diabetic control is achieved and maintained by daily (or even more frequent) self-monitoring of glucose levels in people treated with insulin and by occasional monitoring of the effectiveness of treatment using the A1c test or the fructosamine test.

  • How is the test used?

    Fructosamine testing may be used to help people with diabetes monitor and control their blood glucose levels in cases where the A1c test cannot be used and/or a shorter-term monitoring window is desired. The level of fructosamine in the blood is a reflection of glucose levels over the previous 2-3 weeks. (See the "What is being tested?" section for more on this.) However, what this translates to in regard to outcomes and prognosis is not as validated as with A1c.

    The A1c test is much more well-known and widely accepted because there are firm data that a chronically elevated A1c level predicts an increased risk for certain diabetic complications, such as problems with the eyes (diabetic retinopathy), possibly leading to blindness, kidney disease (diabetic nephropathy), and nerve damage (diabetic neuropathy).

    The American Diabetes Association (ADA) recognizes the usefulness of monitoring glucose control and suggests more frequent self-monitoring of blood glucose or changing the timing of continuous glucose monitoring in situations where A1c cannot be reliably measured. The ADA states that the prognostic significance of the results of a fructosamine test are not as clear as with A1c.

    Instances where fructosamine may be considered over A1c include:

    • Rapid changes in diabetes treatment – fructosamine allows the effectiveness of diet or medication adjustments to be evaluated after a few weeks rather than months.
    • Diabetic pregnancy – in women with diabetes who become pregnant, good glycemic control is essential during pregnancy, and the needs of the mother frequently change during the pregnancy; fructosamine measurements may be ordered along with glucose levels to help monitor and accommodate shifting glucose, insulin, or other medication requirements.
    • Shortened RBC life span – an A1c test will not be accurate when a person has a condition that affects the average lifespan of red blood cells (RBCs), such as hemolytic anemia or blood loss. When the lifespan of RBCs in circulation is shortened, the A1c result is falsely low and is an unreliable measurement of a person's average glucose over time.
    • Abnormal forms of hemoglobin – the presence of some hemoglobin variants, such as hemoglobin S in sickle cell anemia, may affect certain methods for measuring A1c. Furthermore, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommends against the use of the A1c test in patients with the hemoglobin variants HbSS, HbSC, or HbCC as these patients may suffer from conditions that affect the A1c test, such as anemia, increased RBC turn-over, and frequent blood transfusions.

    When is it ordered?

    Although not widely used, the fructosamine test may be ordered whenever a healthcare practitioner wants to monitor a person's average glucose levels over the past 2 to 3 weeks. It is primarily ordered when a diabetic treatment plan is being started or adjusted in order to monitor the effect of the change in diet, exercise, or medication.

    Fructosamine levels also may be ordered periodically when a diabetic woman who has diabetes is pregnant or when a person has an illness that may change their glucose and insulin requirements for a period of time. The fructosamine test may be used when monitoring is required and an A1c test cannot be reliably used, as in cases of a shortened RBC life span or in some cases where the person being tested has an abnormal hemoglobin.

    What does the test result mean?

    A high fructosamine level means that the average blood glucose over the previous 2 to 3 weeks has been elevated. In general, the higher the fructosamine level, the higher the average blood glucose level. Monitoring the trend of values may be more important than a single high value. A trend from a normal to a high fructosamine level may indicate that glucose control is not adequate. This, however, does not pinpoint the cause. A review and adjustment to diet and/or medication may be required to help get glucose under control. Illness and significant stress can also temporarily raise blood glucose levels so these factors may also be taken into account when interpreting results.

    A normal fructosamine level may indicate good glucose control and that the current treatment plan is effective for the individual. Likewise, a trend from high to normal fructosamine levels may indicate that changes to the treatment regimen have been effective.

    Fructosamine results must be evaluated in the context of a person's overall 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 in the urine or digestive tract, or with changes in the type of protein produced by the body. In this case, there may be a discrepancy between the results obtained from daily glucose monitoring and fructosamine testing. Also, someone whose glucose levels swing erratically from high to low may have normal or near normal fructosamine and A1c levels but still have a condition that requires frequent monitoring. However, most people with such unstable diabetic control do have elevated fructosamine and A1c concentrations. 

    Can a fructosamine test be used to screen for diabetes?

    No. Since the fructosamine levels of people with well-controlled diabetes may overlap with those of people who are not diabetic, the fructosamine test is not useful as a screening test for diabetes.

    Can I test for fructosamine at home?

    No. Although a home test was available in the past, it was discontinued in 2002.

    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. Unlike A1c, this test is not recommended for diabetes screening, even if they have a strong family history.

    If I have diabetes, should I have a fructosamine test?

    The vast majority of people with diabetes can be monitored using A1c tests that reflect their glycemic control over the previous 2 to 3 months. Fructosamine testing can be useful during pregnancy when the woman has diabetes, when a person's red blood cells have a shortened lifespan, and in some cases of people with abnormal forms of hemoglobin. Most diabetics will never need to have the test performed.

    Is there anything else I should know?

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

  • View Sources

    Sources Used in Current Review

    2018 review completed by Nadia Ayala-Lopez, PhD, MLS, Postdoctoral Fellow, Yale University.

    American Diabetes Association. (2018). Standards of Medical Care in Diabetes. Diabetes Care, Volume 41, Supplement 1. Available online at Accessed on 10/28/2018.

    National Glycohemoglabin Standarization Program (NGSP). Harmonizing Hemoglobin A1c Testing: Factors that Interfere with HbA1c Test Results. Available online at Accessed on 10/27/2018.

    National Institute of Diabetes and Digestive and Kidney Diseases. Sickle Cell Trait & Other Hemoglobinopathies & Diabetes (For Providers). Available online at Accessed on 10/27/2018.

    Rifai, Nader. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Philadelphia: Saunders, 2018.

    Sources Used in Previous Reviews

    Pagana, Kathleen D. & Pagana, Timothy J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 503-505.

    Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC. Pg 296.

    Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pg 418.

    (2005 June, Updated). Glucose Meters & Diabetes Management. FDA Diabetes Information [On-line information]. Available online through Accessed on 1/30/08.

    Kendall, D. (2005 October 28). Postprandial Blood Glucose in the Management of Type 2 Diabetes: The Emerging Role of Incretin Mimetics. Medscape Diabetes & Endocrinology [On-line information]. Available online through Accessed on 1/30/08.

    Smiley, D. et. al. (2008 January 23). Therapy Insight: Metabolic and Endocrine Disorders in Sickle-cell Disease. Medscape CME [On-line information]. Available online through Accessed on 1/30/08.

    Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

    Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

    ADA (2002). Tests of Glycemia in Diabetes. DiabetesCare 25:S97-S99 [On-line journal]. Journal available online through

    Ko, GT et. Al (1998). Combined use of a fasting plasma glucose concentration and HbA1c or fructosamine predicts the likelihood of having diabetes in high-risk subjects. DiabetesCare [Abstract]. Journal available online through

    Edelman, S. et. Al. (2001 Nov-Dec). Home testing of fructosamine improves glycemic control in patients with diabetes. PubMed from Endocr Pract 7(6): 454-8 [Abstract]. Available online through

    Mik, C. (2002 Fall). Fructosamine vs HbA1c: Which Test is Right for Your Patients? DiabetesSource [On-line newsletter]. PDF available for download at

    (2003 Feb 20, Modified). National Coverage Determinations (NCDs) Glycated Hemoglobin/Glycated Protein. CMS [On-line information]. Available online through

    Fructosamine. ARUP Guide to Clinical Testing [On-line information]. Available online through

    (2003). Home Blood Sugar Monitoring, Home Fructosamine Tests and Hemoglobin A1c Testing. Joslin Diabetes Center [On-line information]. Available online through

    Glycosylated Serum Proteins. FDA, Glucose Meters & Diabetes Management [On-line information]. Available online through

    Armbruster, D. (1987). Fructosamine: structure, analysis, and clinical usefulness. Clinical Chemistry Vol 33, 2153-2163 [Abstract]. Available online through

    (2000). Newly Diagnosed. Children's Diabetes Foundation of the North Bay [On-line information]. Available online through

    Diabetes Facts. Central Ohio Diabetes Association [On-line information]. Available online through

    Juretic, D. (2002). 16. Pre-Analytical, Analytical And Post-Analytical Factors Influencing Specific Tests For Diagnosis And Monitoring Of Dm-National network in quality assessment. eJIFCC vol 13 no5 [On-line journal]. Available online through

    Lusky, K. (2010 January). Fructosamine Testing. CAP Today [On-line information]. Available online through Accessed July 2011.

    Grenache, D. et. al. (Updated 2011 April). Diabetes Mellitus. ARUP Consult [On-line information]. Available online at Accessed July 2011.

    (© 1995–2011). Unit Code 81610: Fructosamine, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at Accessed July 2011.

    Khardori, R. (Updated 2011 June 30). Type 1 Diabetes Mellitus. Medscape Reference [On-line information]. Available online at Accessed August 2011.

    Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 508-510.

    William E. Winter, MD, FACB. Lab Tests Online adjunct board member.

    Kotus, J. and Mayrin, J. (Updated 2014 January 13). Fructosamine. Medscape Drugs & Diseases [On-line information]. Available online at Accessed February 2015.

    Chiang, J. et. al. (2014). Type 1 Diabetes Through the Life Span: A Position Statement of the American Diabetes Association. Medscape Multispecialty from Diabetes Care. v 37 (7):2034-2054. [On-line information]. Available online at Accessed February 2015.

    Melville, N. (2014 January 17). Add Glycated Proteins to HbA1c for Diabetes Risk Prediction? Medscape Multispecialty [On-line information]. Available online at Accessed February 2015.

    (© 1995–2015). Fructosamine, Serum. Mayo Clinic Mayo Medical Laboratories. [On-line information]. Available online at Accessed February 2015.

    Cohen, R. and Sacks, D. (2012 October 31). Comparing Multiple Measures of Glycemia: How to Transition from Biomarker to Diagnostic Test? Clinical Chemistry v 58 (12) 1615–1617 [On-line information]. Available online at Accessed February 2015.

    Juraschek, S. et. al. (2012 December). Associations of Alternative Markers of Glycemia with Hemoglobin A1c and Fasting Glucose. Clinical Chemistry v 58 (12) 1648–1655 [On-line information]. Available online at Accessed February 2015.

    Kishore, P. (Reviewed 2014 June). Diabetes Mellitus (DM). Merck Manual Professional Edition [On-line information]. Available online through Accessed February 2015.