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Also known as: Glycated Serum Protein; GSP
Formal name: Fructosamine

At a Glance

Why Get Tested?

To help monitor your blood glucose (sugar) levels over time if you have diabetes mellitus, especially if it is not possible to monitor your diabetes using the 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 are diabetic and your healthcare provider wants to evaluate your average blood glucose level over the last 2-3 weeks

Sample Required?

A blood sample drawn from a vein in your arm or sometimes from a fingerstick

Test Preparation Needed?


The Test Sample

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. Affected 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 a 2 to 3 week time period.

Keeping blood glucose levels as close as possible to normal helps those 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 insulin-treated diabetics and by occasional monitoring of the effectiveness of treatment using either a fructosamine or A1c test.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm or from a fingerstick.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

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

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

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

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

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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 through Accessed July 2011.

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

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