Which factors can affect the HbAc value

Any condition that reduces the duration of life of the red blood cells or their mean life-span (haemolytic anaemias or an acute haemorrhage), leads to falsely low HbA1c levels, regardless of the method used for its determination. Hypertriglyceridaemia, uraemia, elevated bilirubin and alcoholism have been reported to influence chromatography methods, resulting in falsely elevated HbA1c values. Haemoglobinopathies affect some of the methods regardless of their effect on red blood cells' life span. The results can be false elevations or false decreases, depending on the method used and haemoglobinopathy present. Ion-exchange chromatography methods are affected more, and immunoassays and affinity chromatography methods, less. Nevertheless, most abnormal haemoglobins are recognized during chromatography and their presence should be reported in the result. Fetal haemoglobin (HbF) co-chromatographs with HbA1 and consequently, when increased (as is the case mainly in homozygous b-thalassaemia and much less so in heterozygous), it falsely elevates HbA1c values in some ion-exchange chromatography methods. Immunoassays are not affected when HbF is < 5 percent, but at higher levels it can give falsely low values. Affinity chromatography methods are not affected by an increase in HbF. Haemoglobins S and C (HbS and HbC, found in sickle cell anaemia) falsely lower HbA1c levels.

When there is suspicion of false results due to a haemoglobinopathy, HbA1c determination should be repeated using an alternative method. If the result is still considered unreliable, it is possible to use the fructosa-mine method, which also determines glycosylated serum proteins (mainly albumin). Since the mean lifespan of serum proteins is 17 days, fructo-samine determines glycaemic control of the previous 2-3 weeks. It should be emphasized though that fructosamine determination is also affected by conditions like hyperuricaemia, hypertriglyceridaemia and haemolysis. It is also affected by albumin concentrations. Fructosamine determination is not a very well standardized method and there are no studies associating it with DM complications. Improvement of HbA1c determination methods has rendered fructosamine determination minimally popular.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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