Fructosamine:

Fructosamine: is a compound which can be considered as the result of a reaction between fructose and ammonia or an amine. A fructosamine is also formed from isomerisation of glucose. It  reacts with an amino group of a protein, and so they are known as Glycated Serum Protein (GSP) or Glycated Albumin, and are used to identify the plasma glucose concentration over time and so assess diabetic control.

Glycosylated (or glycated) hemoglobin (hemoglobin A1c, Hb_1c , Hb_A1c or Hg_A1c) is a form of hemoglobin used primarily to identify the plasma glucose concentration over prolonged periods of time. Its name is sometimes abbreviated to A1C. It is formed in a non-enzymatic pathway by hemoglobin's normal exposure to high plasma levels of glucose. Glycation of hemoglobin has been implicated in nephropathy and retinopathy in diabetes mellitus. Monitoring the Hb_A1c in diabetic patients may is used to asses treatment over the last 6 weeks.

Indications and use:

Glycosolated hemoglobin is recommended for measuring of control of DM over 120 days (average life span of red blood cell)
     Hence people with hemolytic anemia, or hemoglobinopathy such as sickle cell disease are not suitable for this test. The alternative fructosamine test may be used in these circumstances and it similarly reflects an average of blood glucose levels over the preceding 2 to 3 weeks.