The genotype group is an independent risk factor for pulmonary hypertension in patients with NTDT. Echocardiography should be routinely recommended for all patients with β-thalassemia. Routine screening in patients with α-thalassemia and combined α and β-thalassemia, however, may not be necessary or should focus on the older population.

Objective: To evaluate an immunochromatographic (IC) strip assay for Hb Bart's as a routine screening test for a-thalassaemia in area with a high prevalence of thalassaemia and haemoglobinopathies. Methods: A total of 300 adult screen positive blood specimens were collected at an ongoing thalassaemia screening programme in northeast Thailand. Routine screening was done using red blood cell indices, osmotic fragility, and dichlorophenolindophenol tests. The IC strip assay for haemoglobin Bart's was performed on all samples. The result was evaluated against thalassaemia genotypes determined using standard haemoglobin and DNA analyses. Results: Of 300 subjects investigated, Hb and DNA analyses identified 32 with normal genotype. The remaining subjects carried thalassaemia with as many as 16 different genotypes. Hb Bart's was detected in all cases, with several a 0 -thalassaemia (SEA type) related disorders. Of cases with a þ -thalassaemia, 86.1% showed a positive result; 100 out of 103 Hb E carriers, all homozygous Hb E and b-thalassaemia trait were negative. Nine out of 17 cases with b-thalassaemia/Hb E disease, and one case of double heterozygote for Hb Q-Thailand and Hb E returned positive results. The overall sensitivity and specificity of the IC strip assay for detecting a 0 -thalassaemia were 100% and 73.1%, respectively. Conclusion: The results showed a high sensitivity for screening for a 0 -thalassaemia using IC strip assay for Hb Bart's. This simple method, used in combination with conventional screening protocols, should lead to a significant reduction in the number of referral cases for DNA analysis. Cost effectiveness in each population should be taken into consideration.

The E-SAAN score is a simple and practical score which can be used as a screening test for PH risk in patients with NTDT.

Patients with nontransfusion-dependent thalassemia (NTDT) do not require regular blood transfusion for survival but may encounter several complications that contribute to morbidity and mortality. We report the molecular heterogeneity and hematological features of NTDT in 312 adult patients in northeast Thailand. Hemoglobin (Hb) and DNA analyses identified 177 subjects with Hb E-β-thalassemia, 1 with homozygous β⁰-thalassemia and 134 with Hb H, AEBart's and EEBart's diseases. For β-thalassemia, 12 different mutations including both β⁰- and β⁺-thalassemias were detected. Coinheritance of α-thalassemia as an ameliorating factor was observed in 18 of 178 cases (10.1%) with β-thalassemia. The α-globin gene triplicated haplotype (ααα^anti3.7) was observed in 1 case of Hb E-β⁰-thalassemia. The presence of the -158 (C→T) ^Gγ-XmnI polymorphism (+/+) was found to be associated with increased Hb F expression, but its frequency in the studied subjects was low. Those with α-thalassemia included 17 with deletional and 51 nondeletional Hb H, and 63 with AEBart's and 3 with EEBart's diseases. The hematological parameters of these NTDT and genotype-phenotype relationships are presented. The diverse molecular heterogeneity of NTDT underlines the importance of complete genotyping of the patient. These results should prove useful for management planning, the prediction of clinical outcome and to improve genetic counseling for NTDT patients.

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