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Introduction: Hemoglobin (Hb) analysis is a key testing for diagnosis of hemoglobinopathies. Accurate analysis, interpretation of results, and genetic risk assessment are important. We report on 8 years of the proficiency testing (PT) program for hemoglobinopathies in Thailand. Methods: Laboratory participants were required to test two simulated PT items in each cycle using capillary electrophoresis, one was a husband and another was his pregnant wife. Related hematological parameters were provided. The participants also provide interpretation and evaluate the risk of having three severe thalassemia diseases in an expected fetus. Three cycles were operated per year in accordance with the ISO17043 and ISO13528 guidelines. A total of 84 laboratories throughout Thailand were participated. Results: A total of 24 PT cycles were performed during 2012‐2019. Most participants had Excellent performance for the PT items with normal, β‐thalassemia trait, hemoglobin E trait, hemoglobin E trait with α‐thalassemia, and Hb H disease. However, when the PT items with homozygous Hb E and Hb E‐β‐thalassemia were tested, an increase in a Needs improvement performance was noted. From 24 PT cycles, the performance with Excellent, Good, Fair, and Needs improvement was ranging from 10.5%‐95.8%, 0%‐11.3%, 0%‐77.2%, and 2.3%‐37.0%, respectively. Conclusion: Most participants have proven their performance to be reliable and demonstrated their abilities to provide interpretation and genetic risk assessment on most of the PT items. For complex thalassemia however, a need to improve the interpretation and risk assessment skills is required which is essential for effective prevention and control of severe thalassemia diseases in Thailand. [ABSTRACT FROM AUTHOR]

Introduction Differentiation of homozygous hemoglobin (Hb) E with and without α0-thalassemia is subtle on routine hematological ground. We examined in a large cohort of homozygous Hb E if the level of Hb A2 is helpful. Methods A total of 592 subjects with homozygous Hb E were recruited from ongoing thalassemia screening program. Additionally, five couples at risk of having fetuses with Hb Bart's hydrops fetalis who were homozygous Hb E were also investigated. Hb analysis was performed using capillary electrophoresis system. Globin genotypes were defined by DNA analysis. Results Subjects were classified into four groups including pure homozygous Hb E (n=532), homozygous Hb E/α0-thalassemia (n=48), Hb Constant Spring EE Bart's disease (n=8), and Hb EE Bart's disease (n=4). The levels of Hb A2 were found, respectively, to be 4.97±0.69, 6.64±1.02, 4.86±0.87, and 7.60±1.04%. Among five couples at risk, α0-thalassemia was identified in three subjects with Hb A2>6.0%. Conclusions Increased Hb A2 level is a useful marker for differentiation of homozygous Hb E with and without α0-thalassemia. This should lead to a significant reduction in number of referral cases of homozygous Hb E for molecular testing of α0-thalassemia in routine practice. [ABSTRACT FROM AUTHOR]

Hemoglobinopathy (abnormal hemoglobin or hemoglobin variant) is an inherited disorder that results in the abnormal structure of globin chains of the hemoglobin (Hb) molecule. Many abnormal Hbs have been characterized worldwide, including more than 20 variants in Thailand. The Bio-Rad Variant II HPLC system is used for investigating hemoglobin variants at Songklanagarind Hospital. This system has been shown to be a sensitive, specific, and reproducible method, but some hemoglobin variants such as Hb Tak and Hb D-Punjab cannot, as yet, be clearly separated by this method. The aim of this study was to investigate the prevalence of hemoglobinopathy in southern Thailand using DNA sequencing and study the severity of each hemoglobin variant. A total of 58 hemoglobin variant samples were obtained from blood samples undergoing routine hemoglobin typing at Songklanagarind Hospital. Genomic DNAs were extracted from the samples, and the globin genes were analyzed by using PCR-direct sequencing. The molecular analysis revealed eight hemoglobin variants: 28 Hb C, 12 Hb D-Punjab, 7 Hb Tak, 4 Hb G-Makassar, 2 Hb Lepore-Hollandia, 2 Hb Q-Thailand, 2 Hb O-Indonesia, and 1 Hb Hope. The distribution of hemoglobin variants in southern Thailand is associated with geographic and/or ethnic backgrounds. This study may help hematologists understand better the prevalence of hemoglobin variants and their hematological features in this region. [ABSTRACT FROM AUTHOR]

Linpisam S (Research Institute for Health Sciences, Chiang Mai University, Thailand), Tienboon P, Promtet N, Putsyalnunt P, Santawanpat and Fuchs G J. Iron deficiency and anaemia in children with a high prevalence of haemo-globinopathies: Implications for screening. International Journal of Epidemiology 1996, 25: 1262–1266.Background Haemoglobin (Hb) concentration is used as a sole test for iron deficiency anaemia (IDA) in most developing countries since most anaemia is believed to be due to iron deficiency and confirmatory testing is generally unavailable. Yet the validity of this approach in regions where haemoglobinopathies are endemic has not been documented. Methods Haemoglobin and serum ferritin (SF) were measured in 559 Northern Thai children aged 6 months to 13 years of age. The sensitivity of SF to identify iron deficiency was also assessed in a subsample of children with low or low normal Hb and normal SF by testing the Hb response to a trial of oral iron. Results While anaemia was common (27%), IDA constituted 19% and none of all anaemia in preschool and school age children, respectively (P < 0.002). Iron depletion was similarly more prevalent in younger children (P < 0.0002). Children with IDA were younger (P < 0.001) and the anaemia more severe (P < 0.0001) compared to those with non-IDA. Of anaemic children with normal SF values who received a therapeutic trial of iron, only 6% responded with an increase in Hb of ≥1g/dl. Conclusions For populations such as ours most anaemia is not due to iron deficiency and a single Hb determination is therefore not acceptable for a presumptive diagnosis of IDA. [ABSTRACT FROM PUBLISHER]