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The Test Sample
What is being tested?
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.