Browsing by Author "Perera, H.L."

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Micro mapping of common alpha thalassaemia deletions (3.7 kb, 4.2 kb) in Sri Lanka and assessment of the contribution of alpha thalassemia to hypochromic microcytosis
(Sri Lanka Medical Association, 2014) Rodriao, B.K.R.P.; Perera, H.L.; Branava, U.; Manamperi, A.A.P.S.; Weatherall, D.J.; Premawardhena, A.P.
INTRODUCTION AND OBJECTIVES: The exact prevalence and distribution of a thalassaemia in Sri-Lanka is not known, and it is widely believed that single gene deletion of a thalassaemia does not cause hypochromic rnicrocytic anaemia. To micro map the distribution of the common athalassaemia deletions in Sri Lanka and to assess its contribution to hypochromic microcytosis in the community. METHODS: A national survey on haemoglobin disorders was carried out between 2009-2010 covering all 25 districts where 300 school children of each district were screened for haemoglobin disorders and anaemia. As part of the survey 3.7 kb and 4.2 kb common alpha plus deletions were analysed using polymerase chain reaction (PCR) Gap PCR in two groups. Group 01,,2038 subjects with hypochromTc rnicrocytic anaemia [MCV < 80 fl; MCH < 27 pg], Group 02, 1305 subjects with normal MCV and MCH. RESULTS: Overall prevalence of a thalassaemia in Sri-Lanka was 9.49 % of which 3.7kb was the commonest deletion (8.27%) whilst the 4.2kb deletion accounted for 1.14%. The distribution of a thalassaemia showed remarkable variabiiity within the districts in Sri Lanka ranging from (16.33%) in Kurunegala to (3.86%) in Galie. Contrary to the present belief a thalassaemia due to single gene deletions is most often associated with hypochromic microcytic anaemia (95%) than not (5%).
Role of red cell distribution width in screening for Hb E trait in population screening for haemoglobin disorders
(Sri Lanka Medical Association, 2013) Nishad, A.A.N.; de Silva, I.S.; Perera, H.L.; Pathmeswaran, A.; Premawardhena, A.P.
INTRODUCTION AND OBJECTIVES: The national screening policy for haemoglobinopathies uses the red cell indices MCV <80 and MCH<27 as cut offs, a strategy known to miss some individuals with Hb E trait (EBT), the commonest abnormal haemoglobin in Sri Lanka. We investigated the possibility of increasing the accuracy of red cell indices in detecting Hb E trait. Objective was to determine if red cell distribution width (RDW) cut off values would help increase sensitivity of screening for Hb E trait. METHODS: Mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and red cell distribution width (RDW) of all samples referred for thalassaemia screening were measured using the Coulter counter. High Performance Liquid Chromatography (HPLC) was carried out as the gold standard to detect haemoglobinopathies. Receiver Operating Characteristic (ROC) curve was drawn to determine the cut-off value for EBT against Beta trait (BTT) and other anaemias. RESULTS: There were 246 BTT, 110 EBT and 151 other anaemias. Mean (SD) MCV of BTT 62.7 (5.9), EBT 73.4 (7.4) and other anaemias 71.3 (8.3) femtolitres (p<0.001). Mean (SD) MCH of BTT 19.6 (2.1), EBT 24 (2.7) and other anaemias 22.8 (3.6) (p<0.001). Mean (SD) RDW among BTT were 16 (2.8), EBT 14.5 (2.9) and other anaemias 15.8 (4.2) (p<0.001). Using 14.45 as cut off for RDW in addition to accepted cut off values for MCV<80 and MCH<27, gave a predictive sensitivity of 98.2% for EBT. DISCUSSION: By using RDW cutoff at 14.45 in addition to the accepted screening indices, sensitivity of Hb E trait detection went up from 86.6% to 98.2%. This study highlights the importance of taking RDW into consideration for screening.
Role of red cell distribution width in screening for Hb Etrait in population ccreening for hemoglobin disorders
(Lippincott Williams and Wilkins, 2014) Nishad, A.A.N.; de Silva, I.S.; Perera, H.L.; Pathmeswaran, A.; Kasturiratne, K.T.A.A.; Premawardhena, A.P.
The national screening policy for hemoglobinopathies uses the cutoffs for red cell indices mean corpuscular volume >80 and mean corpuscular hemoglobin >27, a strategy known to miss some individuals with Hb E trait (EBT), the most common abnormal hemoglobin in Sri Lanka. We wanted to determine if red cell distribution width (RDW) cutoff values would help in increasing the sensitivity of screening for Hb E trait. High-performance liquid chromatography was carried out as the gold standard to detect hemoglobinopathies and red blood cell parameters with colter counter. Receiver operating characteristic curve was drawn to determine the cutoff value for EBT against β-trait (BTT) and other anemias. Of the 504 patients, 246 had BTT, 110 had EBT, and 151 had other types of anemias. Mean (SD) RDW among patients with BTT was 16 (2.8), with EBT 14.5 (2.9), and with other anemias 15.8 (4.2) (P>0.001). With 14.45 as the cutoff for RDW and considering accepted values for mean corpuscular volume >80 and mean corpuscular hemoglobin >27, it gave a predictive sensitivity of 98.2% for EBT. By using RDW cutoff at 14.45 in addition to the accepted screening indices, sensitivity of Hb E trait detection went up to 98.2% from 86.6%. This study highlights the importance of taking RDW into consideration for screening