Fructosamine
What it measures, and what changes the number.
Fructosamine is a measure of glycated serum proteins, mainly albumin, that have bound glucose. Serum proteins turn over faster than red blood cells. Because of this, fructosamine reflects average blood glucose over the previous few weeks, a shorter window than HbA1c.
It is often read alongside HbA1c and glucose, especially when HbA1c may be unreliable, such as with some hemoglobin variants or conditions that change red cell lifespan. Albumin and total protein help put it in context.
Fasting is generally not required. Because the result depends on protein levels, anything that changes albumin concentration can affect it. Some labs report a value corrected for albumin or total protein. Methods differ between labs, so results are easiest to compare within the same lab.
Often read alongside: HbA1c (NGSP), HbA1c (IFCC), Glucose, Albumin, Total protein