Sickle cell disease is an inherited condition characterised by the presence of Haemoglobin S (HB-S). Hb-S exists in a homozygous state (S/S) known as Sickle Cell Anaemia or in a heterozygous state (A/S) known as Sickle Cell Trait. Homozygous individuals (S/S) commonly exhibit symptoms of severe haemolytic anaemia and/or vascular occlusions. Heterozygous individuals (A/S) are usually asymptomatic. Hb-S may be present with other haemoglobins, such as Haemoglonbin A, C or D, or with thalassemia, a condition that interferes with the synthesis of normal haemoglobin.
Under conditions of low oxygen tension, the heterozygous (A/S) form can cause erythrocytes to form the characteristic sickle-shaped tactoids. The formation of these irreversible sickled red blood cells causes the onset of the acute symptoms. Detection of both the homozygous and heterozygous condition is important so high-risk individuals can be identified, and their symptoms reduced.
SICKLEDEX® kit is a qualitative solubility test for testing the presence of sickling haemoglobins in human blood. Deoxygenated Hb-S is insoluble in the presence of a concentrated phosphate buffer solution and forms a turbid suspension that can be easily visualised. Normal Haemoglobin A and other haemoglobins remain in solution under these conditions. These different qualitative outcomes allow for the detection of sickle cell disease and its traits.
SICKLEDEX uses Saponin to lyse the red blood cells. Sodium Hydrosulfite then reduces the released haemoglobin. Reduced Hb-S is insoluble in the concentrated phosphate buffer and forms a cloudy turbid suspension. Other sickling haemoglobin subtypes may also give a positive result.
Preparation of patients: There is no physical preparation for the test.
Precautions: Frozen, clotted, or grossly haemolysed samples cannot be analysed.
