The reference range for Haemoglobin A2 (HbA2) by the microcolumn technique is not well defined. Various textbooks and inserts give different reference ranges. This leads to confusion in interpretation. Normal Saudi individuals were checked by the method, excluding all disease in them that can affect HbA2 level. The reference range obtained was 2.0-2.7 (mean+SD). This new range will decrease remarkably the overlap between normal, alpha thalassemia trait and beta thalassemia trait individuals.
Also>, and in spite of the claim by the manufacturer to the contrary, it was shown that presence of sickle haemoglobin, places the assay of Hb A2 significantly outside the normal range> using a column that is supposed to be just for the purpose of accurate assay of Hb A2 in presence of HbS. The range in sickle trait patients was shown to be 2.5-3.4 (mean+SD).
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