Screening for α⁰-thalassemia is usually associated with a high false-positive rate, leading to an unnecessary PCR workload for accurate diagnosis. We have developed a modified Hb H inclusion test for use as a secondary screening. This test was performed on young red blood cell enriched fractions using dextran sedimentation. The study was performed in 100 subjects positive on initial screening. Confirmatory tests included Hb analysis and a multiplex PCR assay to identify α⁰-thalassemia deletions. A modified Hb H inclusion test was positive in 31 cases, 30 of whom were α⁰-thalassemia carriers (97%). The remaining case (3.0%) was homozygous for α+-thalassemia. The remaining 69 cases with a negative Hb H inclusion test included normal subjects, α+-thalassemia carriers and β-thalassemia carriers. Two of them (2/69, 3.0%) were found to be double heterozygotes for β⁰-thalassemia and α⁰-thalassemia. The overall sensitivity and specificity of the modified Hb H inclusion test for screening of α⁰-thalassemia were 94.0 and 99.0%, respectively. Therefore, we recommend the use of this test in combination with Hb analysis to exclude cases with αβ-thalassemia. This should lead to a significant reduction in the number of cases referred for PCR analysis of α⁰-thalassemia by about 50.0%.

Keywords:
Hemoglobin H inclusion, α0-Thalassemia, Thalassemia screening
1.
Weatherall DJ, Clegg JB: Inherited haemoglobin disorders: an increasing global health problem. Bull World Health Organ 2001;79:704-712.
2.
Fucharoen S, Winichagoon P: Thalassemia in Southeast Asia: problem and strategy for prevention and control. Southeast Asian J Trop Med Public Health 1992;23:647-655.
3.
Fucharoen G, Sanchaisuriya K, Sae-ung N, Dangwibul S, Fucharoen S: A simplified screening strategy for thalassemia and haemoglobin E in rural communities in south-east Asia. Bull World Health Organ 2004;82:364-372.
4.
Sanchaisuriya K, Fucharoen S, Fucharoen G, Ratanasiri T, Sanchaisuriya P, Changtrakul Y, Ukosanakarn U, Ussawaphark W, Schelp FP: A reliable screening protocol for thalassemia and hemoglobinopathies in pregnancy: an alternative approach to electronic blood cell counting. Am J Clin Pathol 2005;123:113-118.
5.
Savongsy O, Fucharoen S, Fucharoen G, Sanchaisuriya K, Sae-ung N: Thalassemia and hemoglobiniopathies in pregnant Lao women: carrier screening, prevalence and molecular basis. Ann Hematol 2008;87:647-654.
6.
Sangkitporn S, Sangkitporn S, Sangnoi A, Supangwiput O, Tanphaichitr SV: Validation of osmotic fragility test and dichlorophenol indophenol precipitation test for screening of thalassemia and Hb E. Southeast Asian J Trop Med Public Health 2005;36:1538-1542.
7.
Sanchaisuriya K, Fucharoen S, Ratanasiri T, Sanchaisuriya P, Fucharoen G, Dietz E, Schelp FP: Thalassemia and hemoglobinopathies rather than iron deficiency are major causes of pregnancy related anemia in northeast Thailand. Blood Cells Mol Dis 2006;37:8-11.
8.
Jopang Y, Thinkhamrop B, Puangpruk R, Netnee P: False positive rates of thalassemia screening in rural clinical setting: 10-years experience in Thailand. Southeast Asian J Trop Med Public Health 2009;40:576-580.
9.
Chaibunruang A, Pornphannukool S, Sae-ung N, Fucharoen G, Sanchaisuriya K, Fucharoen S: Improvement of α0-thalassemia screening using combined osmotic fragility, dichlorophenolindophenol and Hb H inclusion tests. Clin Lab 2010;56:111-117.
10.
Fucharoen S, Sanchaisuriya K, Fucharoen G, Panyasai S, Devenish R, Luy L: Interaction of hemoglobin E and several forms of α-thalassemia in Cambodian families. Haematologica 2003;88:1092-1098.
11.
Boonsa S, Sanchaisuriya K, Fucharoen G, Wiangnon S, Jetsrisuparb A, Fucharoen S: The diverse molecular basis and hematologic features of Hb H and AEBart's diseases in northeast Thailand. Acta Haematol 2004;111:149-154.
12.
Yamsri S, Sanchaisuriya K, Fucharoen G, Sae-ung N, Fucharoen S: Genotype and phenotype characterizations in a large cohort of β-thalassemia heterozygote with different forms of α-thalassemia in northeast Thailand. Blood Cells Mol Dis 2011;47:120-124.
13.
Chui DHK, Waye JS: Hydrops fetalis caused by α-thalassemia: an emerging health care problem. Blood 1998;91:2213-2222.
14.
Pan LL, Eng HL, Kuo CY, Chen WJ, Huang HY: Usefulness of brilliant cresyl blue staining as an auxiliary method of screening for α-thalassemia. J Lab Clin Med 2005;145:94-97.
15.
Skogerboe KJ, West SF, Smith C, Terashita ST, LeCrone CN, Detter JC, Tait JF: Screening for alpha-thalassemia: correlation of hemoglobin H inclusion bodies with DNA-determined genotype. Arch Pathol Lab Med 1992;116:1012-1018.
16.
Fucharoen S, Fucharoen G, Sae-ung N, Sanchaisuriya K: Thalassemia intermedia associated with the Hb Constant Spring EE Bart's disease in pregnancy: a molecular and hematological analysis. Blood Cells Mol Dis 2007;39:195-198.
17.
Sabath DE, Cross ST, Mamiya LY: An improved method for detecting red cells with hemoglobin H inclusions that does not require glass capillary tubes. Clin Lab Haematol 2003;25:87-91.
18.
Jopang Y, Fucharoen G, Kitcharoen K, Sae-ung N, Sanchaisuriya K: Simple laboratory screening tests for thalassemias and abnormal hemoglobins (in Thai). Bull Med Tech Phys Ther 1993;5:131-137.
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2013
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