HbA2 Haemoglobin A2 Test

Haemoglobin is the substance in the blood which carries oxygen (air) around the body and makes the blood look red in colour. Every unborn baby produces a minor adult type haemoglobin called Hemoglobin A2; this haemoglobin is produced irrespective of the type of major adult haemoglobin they have inherited from their parents. Haemoglobin A2 is useful for helping the laboratory to diagnose some genetic mutations of haemoglobin, depending on the type of genetic mutation that has been inherited the level of A2 will rise or fall.

There is no need to disturb your diet routine. You can eat and drink normally. There are no particular preparations needed for the test.

A haemoglobin A2 test is done in order to screen for and/or diagnose a haemoglobin disorder. The HBA2 gene provides instructions for making a protein called alpha-globin. Alpha-globin is a component of a larger protein i.e. haemoglobin. Deletions of the HBA2 genes are the most common cause of alpha thalassemia which is a blood disorder that reduces the production of haemoglobin. In people with the characteristic features of alpha thalassemia, a reduction in the amount of haemoglobin prevents enough oxygen from reaching the body's tissues. Affected individuals also have a shortage of red blood cells (anemia), which can cause pale skin, weakness, fatigue, and more serious complications.

A blood sample will be obtained directly from you. The health professional taking a sample of your blood will:

• An elastic band will be wrapped around your upper arm to make the veins below the band more visible, which aids the process.
• Clean your skin with an alcohol pad.
• Insert the needle into the vein to draw out blood.
• The blood is dragged out from the needle by a nozzle.
• The band is removed after enough blood is acquired.
• A cotton ball is put over the needle site as the needle is removed.
• Pressure is applied on the site and then a bandage is put.
• The sample is then sent to a laboratory for testing.