Anemia, iron deficiency, and thalassemia among the Thai population inhabiting at the Thailand-Lao PDR-Cambodia triangle.

Anemia is a major public health problem in many areas of Southeast Asia. Ascertaining anemia and defining its underlying causes is essential for providing appropriate care, management, and establishment of a control program. Limited studies on these have been carried out on people living at the borders of Thailand, Lao PDR, and Cambodia. This cross-sectional study was done in four areas along the borders of Thailand, Lao PDR, and Cambodia. Blood specimens were collected from subjects aged 15-18 years in four districts including Kantharalak, Si Sa Ket province (n = 36), Nam Khun (n = 109), Nam Yuen (n = 98), and Na Chaluai (n = 128), Ubon Ratchathani province, Thailand. RBC parameters were recorded, and serum ferritin (SF) level was measured. Diagnosis of thalassemia and hemoglobinopathies was based on hemoglobin (Hb) and DNA analyses. Measurement of C-reactive protein was performed to exclude false-negative result of iron deficiency. The prevalence of anemia was found to be 25.1%. ID accounted for only 10.5%. Various types of thalassemia were identified in 67.7% of the subjects. The overall prevalence of thalassemia included 3.5% α0-thalassemia, 0.8% ß-thalassemia, 47.7% Hb E, and 53.6% α+-thalassemia. The proportions of ID, thalassemia and combined ID and thalassemia among anemic subjects were 6.5%, 66.6%, and 20.4%, respectively. The results indicate that thalassemia and hemoglobinopathies rather than ID are major causes of anemia in Thailand-Lao PDR-Cambodia triangle. This information should prove useful for implementing an anemia control program in the regions.

Southeast Asian Ovalocytosis and Hemoglobinopathies in Newborns: Prevalence, Molecular, and Hematologic Analyses.

OBJECTIVES: Southeast Asian ovalocytosis (SAO) is an inherited red blood cell (RBC) membrane disorder, whereas hemoglobinopathies are inherited globin gene disorders. In an area where both diseases are prevalent, the interaction between them resulting in variable hematologic parameters can be encountered. However, little is known about the genetic interaction of SAO and thalassemia. We investigated the prevalence of SAO and hemoglobinopathy genotypes among newborns in southern Thailand. PATIENTS AND METHODS: This study was carried out on 297 newborns recruited consecutively at Naradhiwas Rajanagarindra Hospital in the south of Thailand. The SAO was identified on blood smear examination and polymerase chain reaction analysis. Thalassemia genotypes were defined. Hematologic parameters and hemoglobin (Hb) profiles were recorded and analyzed. RESULTS: Among 297 newborns, 15 (5.1%) carried SAO, whereas 70 (23.6%) had thalassemia with 15 different thalassemia genotypes. Abnormal Hb including Hb C, Hb Q-Thailand, and Hb D-Punjab were observed in 5 newborns. It was found in the nonthalassemic newborns that RBC count, Hb, and hematocrit of the nonthalassemic newborns with SAO were significantly lower than those without SAO. The same finding was also observed in the thalassemic newborns; RBC count, Hb, and hematocrit of the thalassemic newborns with SAO were significantly lower than those without SAO. However, the mean corpuscular volume, mean corpuscular Hb, and RBC distribution width of the SAO-newborns were significantly higher. CONCLUSIONS: Both SAO and hemoglobinopathy genotypes are common in southern Thailand. One should take this into consideration when evaluating neonatal anemia and other hematologic abnormalities. Identification of both genetic defects and long-term monitoring on the clinical outcome of this genetic interaction should be essential to understand the pathogenesis of these common genetic disorders in the region.

A New Indicator Derived From Reticulocyte Hemoglobin Content for Screening Iron Deficiency in an Area Prevalent for Thalassemia.

OBJECTIVE: To establish a new indicator derived from reticulocyte hemoglobin (Ret-He) content and red blood cell (RBC) indices for screening for iron deficiency anemia (IDA) in an area in whch thalassemia is prevalent. METHODS: Blood specimens from 304 women aged between 18 and 30 years residing in northeast Thailand were collected and measured for RBC and reticulocyte parameters. Iron deficiency was diagnosed when a participant had a serum ferritin level of less than 15 ng per mL. Thalassemia genotypes were defined by hemoglobin (Hb) and DNA analyses. RESULTS: Of the total participants, 25% had iron deficiency (ID) and 50% carried the thalassemia gene. Various mathematical formulas were established and analyzed using the receiver operating characteristic (ROC) curve. The formula derived from Ret-He: (Ret-He/RDW-SD) × 10, was the best predictor for identifying ID among participants (area under the curve [AUC] = 0.812). Further testing of this indicator among individuals with positive thalassemia-screening results revealed stronger performance with an AUC of 0.874. CONCLUSIONS: The findings indicate that the formula derived from Ret-He might be applicable for screening ID in areas in which thalassemia is prevalent.

Factors associated with anaemia and iron deficiency among women of reproductive age in Northeast Thailand: a cross-sectional study.

BACKGROUND: Anaemia and iron deficiency (ID) affect women of reproductive age globally and considered to be a major public health problem in developing countries. This study determines the prevalence of anaemia and ID among women of reproductive age in urban northeast Thailand and examined the relative contribution of various risk factors to anaemia and ID in this population. METHODS: Three hundred ninety-nine non-pregnant women, aged 18-45 years, from three universities in northeast Thailand participated in this cross-sectional study. Selected socio-demographic, history of blood loss, usual consumption of red meat and tea/coffee, and anthropometric data were collected. Complete blood count including haemoglobin (Hb) concentration, serum ferritin (SF), C-reactive protein (CRP), and thalassemia were determined. Multiple logistic regressions were applied to identify the risk factors of anaemia and ID. RESULTS: Overall, 370 participants were included for data analyses after excluding women with severe/intermedia thalassemia diseases and/or those with positive serum CRP. The prevalence of anaemia, ID, and iron deficiency anaemia (IDA) were 28.4, 28.4, and 13.2%, respectively. Women with thalassemia had a higher prevalence of anaemia but a lower prevalence of ID than the women without thalassemia. By multiple regression analysis, ID [adjusted OR (AOR) = 4.9, 95% CI = 2.8-8.3], two α-gene defects (AOR = 8.0, 95% CI = 3.0-21.3) and homozygous Hb E (AOR = 8.5, 95% CI = 3.0-24.3) were identified as the potential risk factors of anaemia. Further, the odds of ID were significantly higher among women who donated blood within the past 3 months (AOR = 6.7, 95% CI = 2.8-16.3), and had moderate to a high amount of blood loss during menstruation (AOR = 2.2, 95% CI = 1.3-3.9). CONCLUSION: This study found a relatively high but differential prevalence of anaemia and ID among women of reproductive age with or without thalassemia. Only homozygous Hb E and two α-gene defects of thalassemia types and ID were the main factors contributing to anaemia. Recent blood donation, and moderate to a high amount of blood loss during menstruation were potential risk factors of ID in this population.

Thalassemia and Hemoglobinopathies in an Ethnic Minority Group in Northern Vietnam.

This study assessed thalassemia and hemoglobinopathies in a group of the Tay ethnic minority. Participants included 289 women of reproductive-age who enrolled in a pilot screening program for thalassemia conducted at six communities of Thai Nguyen Province, northern Vietnam. Standard procedures including complete blood count (CBC), hemoglobin (Hb) and DNA analyses were performed for all samples. The prevalence of thalassemia in 289 Tay women was 15.6% (gene frequency 0.078) for α0-thalassemia (α0-thal), 10.0% (gene frequency 0.050) for α+-thal, 7.3% (gene frequency 0.036) for ß-thalassemia (ß-thal), 2.4% (gene frequency 0.012) for Hb Constant Spring [Hb CS; α142, Term→Gln, TAA>CAA (α2), HBA2: c.427T>C] and 1.7% (gene frequency 0.009) for Hb E [ß26(B8)Glu→Lys, GAG>AAG; HBB: c.79G>A]. Further analysis of ß-globin gene abnormalities identified four mutations including codons 41/42 (-TCTT) (HBB: c.126_129delCTTT), codon 17 (A>T) (HBB: c.52A>T), codons 71/72 (+A) (HBB: c.216_217insA), and -28 (A>G) (HBB: c.78A>G). The results hint at the remarkably high frequencies of severe forms of thalassemia that indicate a serious public health problem requiring further exploration, and most probably, also intervention within the country.

Erythrocyte indices in a large cohort of ß-thalassemia carrier: Implication for population screening in an area with high prevalence and heterogeneity of thalassemia.

INTRODUCTION: Most ß-thalassemia carriers have hypochromic microcytosis with mean corpuscular volume (MCV) < 80 fL and mean corpuscular hemoglobin (MCH) < 27 pg. These can be variable due to ß-thalassemia mutations, genetic interaction between thalassemic genes, and blood cell counters. We have examined whether these indices are effective in screening of ß-thalassemia in Thailand where thalassemia is prevalence and heterogeneous. METHODS: Retrospective data were reviewed on 11 443 Thai subjects encountered from August 2014 to August 2017. Subjects with heterozygous ß-thalassemia based on Hb and DNA analyses were recruited along with MCV and MCH values and analyzed. RESULTS: Among the 11 443 subjects reviewed, 1425 were ß-thalassemia carriers. Data were available on 1214 subjects for MCV and 965 subjects for MCH. DNA analysis identified 20 different ß0 -thalassemia mutations in 874 (72.0%) cases and 6 ß+ -thalassemia mutations in 340 (28.0%) subjects. Of these 1214 carriers, 26 (2.1%) had MCV ≥ 80 fL; 6 (23.1%) carried ß0 -thalassemia, and the remaining 20 (76.9%) had ß+ -thalassemia. In contrast for those having MCH values, only 4 of 965 (0.4%) had MCH ≥ 27 pg. DNA analysis identified both ß0 -thalassemia and ß+ -thalassemia mutations. CONCLUSIONS: Using MCV alone for the screening of ß-thalassemia may pose a significant number of false negative although three-quarter of them are carriers of mild ß+ -thalassemia. MCH with approximately five times more sensitive is a better screening marker. Using a combined MCV and MCH is highly recommended, especially in an area with high prevalence and heterogeneity of thalassemia like Thailand.

Presentation of Compound Heterozygous Hemoglobin Constant Spring and Hemoglobin Pakse in Neonates.

BACKGROUND: Mutations causing α thalassemia are divided into deletion and nondeletion groups. In the nondeletion group, hemoglobin constant spring (Hb CS) and hemoglobin Pakse (Hb Pakse) are both caused by a termination codon mutation leading to elongation of the α2 globin gene. In the case of Hb CS, the mutation is TAA→CAA, whereas the mutation causing Hb Pakse is TAA→TAT. Clinical hematologic phenotypes are not significantly different. It is important to identify compound heterozygotes for purposes of genetic counseling. METHODS: We report 5 neonates with compound heterozygous Hb CS/Hb Pakse mutations with respect to clinical courses, hematologic profiles, and management. RESULTS: Among 5 cases (3 male babies and 2 female babies) with mean birth weight 2982 g (range, 2660 to 3440 g), 3 were diagnosed as compound heterozygous Hb CS/Hb Pakse, 1 as homozygous Hb E with compound heterozygous Hb CS/Hb Pakse, and 1 as heterozygous Hb E with compound heterozygous Hb CS/Hb Pakse. Clinical manifestations included fetal anemia (1 case), neonatal hyperbilirubinemia (5), neonatal anemia (2), hepatosplenomegaly (1), and cholestatic jaundice (1). Three cases required a single phototherapy; 2 cases needed double phototherapy for treatment of severe hyperbilirubinemia. During the first few months of life, all cases had mild anemia, slightly low mean corpuscular volume, wide red cell distribution width, and low red cell counts. At 1 to 3 years of age, all patients still had mild microcytic hypochromic anemia with Hb levels around 10 g/dL, increased reticulocyte count, and wide red cell distribution width. CONCLUSIONS: Misdiagnosis of Hb Pakse could occur via Hb typing using Hb electrophoresis, because the band comigrates with that of Hb CS. DNA study is the definitive method for diagnosis.

Clinical Course of Homozygous Hemoglobin Constant Spring in Pediatric Patients.

BACKGROUND: Hemoglobin (Hb) Constant Spring is an alpha-globin gene variant due to a mutation of the stop codon resulting in the elongation of the encoded polypeptide from 141 to 172 amino acid residues. Patients with homozygous Hb Constant Spring are usually mildly anemic. METHODS: We retrospectively describe clinical manifestations, diagnosis, laboratory investigations, treatment, and associated findings in pediatric patients with homozygous Hb Constant Spring followed-up at Srinagarind Hospital. RESULTS: Sixteen pediatric cases (5 males and 11 females) were diagnosed in utero (N=6) or postnatal (n=10). Eleven cases were diagnosed with homozygous Hb Constant Spring, 4 with homozygous Hb Constant Spring with heterozygous Hb E, and 1 with homozygous Hb Constant Spring with homozygous Hb E. Three cases were delivered preterm. Six patients had low birth weights. Clinical manifestations included fetal anemia in 6 cases, hepatomegaly in 1 case, hepatosplenomegaly in 2 cases, splenomegaly in 1 case. Twelve cases exhibited early neonatal jaundice, 9 of which required phototherapy. Six cases received red cell transfusions; 1 (3), >1 (3). After the first few months of life, almost all patients had mild microcytic hypochromic anemia and an increased reticulocyte count with a wide red cell distribution (RDW), but no longer required red cell transfusion. At 1 to 2 years of age, some patients still had mild microcytic hypochromic anemia and some had normocytic hypochromic anemia with Hb around 10 g/dL, increased reticulocyte count and wide RDW. Associated findings included hypothyroidism (2), congenital heart diseases (4), genitourinary abnormalities (3), gastrointestinal abnormalities (2), and developmental delay (1). SUMMARY: Pediatric patients with homozygous Hb Constant Spring developed severe anemia in utero and up to the age of 2 to 3 months postnatal, requiring blood transfusions. Subsequently, their anemia was mild with no evidence of hepatosplenomegaly. Their Hb level was above 9 g/dL with hypochromic microcytic blood pictures as well as wide RDW. Blood transfusions have not been necessary since then.

Elevations of Thrombotic Biomarkers in Hemoglobin H Disease.

BACKGROUND: Thalassemia is a group of hereditary hemoglobinopathies caused by decreased or absent synthesis of α and/or ß globin chains. Studies have shown that hypercoagulability and thrombosis are common clinical symptoms in ß-thalassemia, especially ß-thalassemia intermedia, but little is known about in α-thalassemia. This study aims to examine phosphatidylserine (PS) levels, platelet activation, and coagulation markers in splenectomized (S) and nonsplenectomy (NS) patients with hemoglobin (Hb) H disease. METHODS: The NS group comprised 20 patients (median age 15.0 years, range, 14-16.5 years), and the S group consisted of 11 patients (median age 16.4 years, range, 14-19.9 years) with Hb H disease; the control group consisted of 20 normal subjects. Hematological parameters were collected. Flow cytometry was used to measure PS exposure on red blood cells. The levels of intercellular adhesive molecule (ICAM)-1, tumor necrosis factor α (TNFα), ß-thromboglobulin (TG) and prothrombin fragment 1 + 2 (F1.2) were determined using ELISA test kits. RESULTS: Significant increases in the levels of PS, ICAM-1, TNFα, ß-TG, and F1.2 were observed in both patient groups compared to normal controls (p < 0.01). CONCLUSION: This observation indicates blood coagulation, endothelial injury, chronic low-grade inflammation, platelet activation, and thrombin generation are present in Hb H disease; these findings merit further assessment in a larger prospective cohort to establish possible links with thrombotic manifestations.

Evaluation of staff performance and interpretation of the screening program for prevention of thalassemia.

INTRODUCTION: Thalassemia screening program has been implemented for years in Southeast Asia, but no external quality assessment program has been established. We have developed and initiated the proficiency testing (PT) program for the first time in Thailand with the aim to assess the screening performance of laboratory staff and their competency in interpretation of the screening results. MATERIALS AND METHODS: Three PT cycles per year were organized. From the first to the third cycle of the PT scheme, a total number of participant laboratories increased from 59 to 67. In each cycle, 2 PT items (assigned as blood samples of the couple) were provided. Performance evaluation was based on the accuracy of screening results, i.e. mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and the dichlorophenolindophenol (DCIP) test for haemoglobin E, including the competency in interpretation of screening results and assessment of foetal risk. Performance was assessed by comparing the participants' result against the assigned value. RESULTS: Of all 3 cycles, most laboratories reported acceptable MCV and MCH values. From the first to the third cycle, incorrect DCIP test and misinterpretation rates were decreased while incorrect risk assessment varied by cycle to cycle. Combining the accuracy of thalassemia screening and the competency in interpretation and risk assessment, approximately half of participants showed excellent performance. CONCLUSION: Improved performance observed in many laboratories reflects the achievement and benefit of the PT program which should be regularly provided.

Screening of (-SEA) α-thalassaemia using an immunochromatographic strip assay for the ζ-globin chain in a population with a high prevalence and heterogeneity of haemoglobinopathies.

AIMS: The presence of the ζ-globin chain is a good marker of (--SEA) α0-thalassaemia. We evaluated an immunochromatographic (IC) strip assay for ζ-globin in screening for (--SEA) α0-thalassaemia in a population with a high prevalence and heterogeneity of haemoglobinopathies. METHODS: The study was carried out on 300 screen positive blood samples of Thai individuals. The IC strip assay for the ζ-globin chain was performed on all samples. The results were interpreted with thalassaemia genotyping using standard haemoglobin and DNA analyses. RESULTS: Several thalassaemia genotypes were noted. Among the 300 subjects investigated, 79 had a positive IC strip assay for ζ-globin and (--SEA) α0-thalassaemia was identified in 40 of them. No (--SEA) α0-thalassaemia was detected in the remaining 39 samples with a positive IC strip test result or in the 221 samples with a negative IC strip test result. Further DNA analysis identified α+-thalassaemia in 25 of the 39 (--SEA) α0-thalassaemia negative samples. Using this IC strip assay in combination with a conventional screening protocol for (--SEA) α0-thalassaemia could provide sensitivity and specificity of 100% and 90.4%, respectively. CONCLUSIONS: IC strip assay for ζ-globin is simple, rapid and does not require sophisticated equipment. Use of this test in addition to the existing screening protocol could detect potential (--SEA) α0-thalassaemia leading to a significant reduction in the workload of DNA analysis. This could be used in areas where haemoglobinopathies are prevalent and heterogeneous but molecular testing is not available.

FLT3-ITD Mutations in Acute Myeloid Leukemia Patients in Northeast Thailand.

The FLT3-ITD mutation is one of the most frequent genetic abnormalities in acute myeloid leukemia (AML) where it is associated with a poor prognosis. The FLT3-ITD mutation could, therefore, be a potential molecular prognostic marker important for risk-stratified treatment options. We amplified the FLT3 gene at exon 14 and 15 in 52 AML patients (aged between 2 months and 74 years) from 4 referral centers (a university hospital and 3 regional hospitals in Northeast Thailand), using a simple PCR method. FLT3-ITD mutations were found in 10 patients (19.2%), being more common in adults than in children (21.1% vs. 14.3%) and more prevalent in patients with acute promyelocytic leukemia (AML-M3) than AML-non M3 (4 of 10 AML-M3 vs. 6 of 42 AML- non M3 patients). Duplication sequences varied in size-between 27 and 171 nucleotides (median=63.5) and in their location. FLT3-ITD mutations with common duplication sequences accounted for a significant percentage in AML patients in northeastern Thailand. This simple PCR method is feasible for routine laboratory practice and these data could help tailor use of the national protocol for AML.

Molecular Understanding of Non-Transfusion-Dependent Thalassemia Associated with Hemoglobin E-ß-Thalassemia in Northeast Thailand.

Non-transfusion-dependent thalassemia (NTDT) is associated with various forms of thalassemia and genetic modifiers. We report the molecular basis of NTDT in hemoglobin (Hb) E-ß-thalassemia disease. This study was done in 73 adult patients encountered at the prenatal diagnosis center of Khon Kaen University, Northeast Thailand. Hematological parameters and Hb patterns were collected, and α- and ß-globin gene mutations were determined. Multiple single-nucleotide polymorphisms (SNPs) including the rs7482144/Gγ-XmnI polymorphism, rs2297339, rs2838513, rs4895441, and rs9399137 in the HBS1L-MYB gene, rs4671393 and rs11886868 in the BCL11A gene, and G176AfsX179 in the KLF1 gene were examined. Five ß0-thalassemia mutations and a severe ß+-thalassemia mutation in trans to the ßE gene were identified. No significant difference in hematological parameters was observed among ß-thalassemia genotypes. Coinheritance of α-thalassemia was observed in 31 of the 73 subjects (42.5%). Four SNPs including Gγ-XmnI, rs2297339, rs4895441, and rs9399137 of HBS1L-MYB were found to be associated with high Hb F levels in 39 (53.4%) subjects. The molecular basis of NTDT in the remaining 3 (4.1%) cases could not be defined. These results indicate multiple genetic factors in NTDT patients and underline the importance of complete genotyping to provide proper management, make clinical predictions, and improve genetic counseling.

PILOT SCREENING PROGRAM FOR THALASSEMIA IN A COUNTRY WITH LIMITED RESOURCES: A COLLABORATION MODEL BETWEEN CLOSE NEIGHBORING COUNTRIES.

Screening for thalassemia carriers should not only be conducted in middle-income countries but also can be possible in low-middle income countries, through cooperation of experienced professionals from middle income countries. We describe a collaborating model between two close neighboring countries in establishing such a screening program for thalassemia. After training and setting up of facilities, a total of 152 out of 187 hospital staff were screened as a pilot activity to encourage community participation. Referring system for sending blood samples to a reference center in Thailand was also established. Among 152 health staff, 12.5% α0-thal, 2% ß-thal and 13% Hb E carriers were found. Applying thalassemia screening to 411 pregnant women and 71 spouses, 5 couples at risk of bearing a child of thalassemia disease were identified. The thalassemia screening program has a sensitivity of 99.5%, specificity of 77%, positive predictive value of 73%, and negative predictive value of 99.5%. Thus, it is possible to operate a thalassemia screening program with acceptable performance in a low-middle income country (Lao People's Democratic Republic) with the cooperation of a referral center located within close proximity in a middle income country (Thailand).

Known and new hemoglobin A2 variants in Thailand and implication for ß-thalassemia screening.

BACKGROUND: We reported molecular and hematological characteristics of δ-globin chain variants and addressed diagnostic consideration of complex hemoglobinopathies caused by their interactions with α- and ß-thalassemias. METHODS: Study was done on four unrelated Thai subjects with second Hb A2 fractions. Hb analysis was carried out using automated HPLC and capillary electrophoresis. Mutations were identified by DNA analysis. Novel diagnostic methods based on PCR-RFLP and allele specific PCR were developed. RESULTS: Hb analysis revealed Hb A2 variant in all cases. DNA analysis of δ-globin gene identified the Hb A2-Melbourne [δ43(CD2)Glu→Lys] in combination with α(+)-thalassemia, α(0)-thalassemia and ß(0)-thalassemia in the first three cases, respectively. Analysis of the remaining case identified a novel δ-Hb variant namely the Hb A2-Lampang [δ47(CD6)GAT→AAT; Asp→Asn] found in association with Hb E and α(+)-thalassemia. These mutations could be identified using PCR-RFLP and allele specific PCR assays developed. CONCLUSIONS: It is necessary to recognize the Hb A2 variant and to combine the amounts of Hb A2 and Hb A2-variant for a total Hb A2 value to make better diagnostic of these complex syndromes. Co-inheritance of these multiple globin gene defects could lead to complex hemoglobinopathies requiring comprehensive Hb and molecular assessments.

Routine screening for α-thalassaemia using an immunochromatographic strip assay for haemoglobin Bart's.

OBJECTIVE: To evaluate an immunochromatographic (IC) strip assay for Hb Bart's as a routine screening test for α-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 α(0)-thalassaemia (SEA type) related disorders. Of cases with α(+)-thalassaemia, 86.1% showed a positive result; 100 out of 103 Hb E carriers, all homozygous Hb E and ß-thalassaemia trait were negative. Nine out of 17 cases with ß-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 α(0)-thalassaemia were 100% and 73.1%, respectively. CONCLUSION: The results showed a high sensitivity for screening for α(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.

A newly modified hemoglobin H inclusion test as a secondary screening for α(0)-thalassemia in Southeast Asian populations.

Screening for α(0)-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 α(0)-thalassemia deletions. A modified Hb H inclusion test was positive in 31 cases, 30 of whom were α(0)-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 ß-thalassemia carriers. Two of them (2/69, 3.0%) were found to be double heterozygotes for ß(0)-thalassemia and α(0)-thalassemia. The overall sensitivity and specificity of the modified Hb H inclusion test for screening of α(0)-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 αß-thalassemia. This should lead to a significant reduction in the number of cases referred for PCR analysis of α(0)-thalassemia by about 50.0%.

Burden of anemia in relation to thalassemia and iron deficiency among Vietnamese pregnant women.

BACKGROUND AND AIMS: Information about the extent to which anemia is related to thalassemia and iron deficiency (ID) is not available in Vietnam. This study investigated the burden of anemia in relation to thalassemia and ID among Vietnamese pregnant women. METHODS: A cross-sectional study was conducted in Thua Thien Hue, Central Vietnam. Blood samples taken from 399 pregnant women with a gestational age <12 weeks were analyzed. Anemia was defined as Hb levels <11 g/dl, and ID as ferritin values <15 ng/ml. RESULTS: Out of 399 participants, 77 (19.3%) were anemic. While the prevalence of ID was 20.1%, the prevalence of ID anemia was 6.0%. The overall prevalence of thalassemia was 7.3%. Of the 77 anemic women, 24 (31.2%) had ID, and 20 (26.0%) had thalassemia genes. The rest (42.9%) were anemic due to unknown causes. CONCLUSIONS: The results indicate that ID remains a significant health burden among the study population, together with anemia caused by unknown factors. Thalassemias appear not to contribute to a great extent to anemia among Vietnamese pregnant women. Other causes need to be investigated further in order to develop an effective control program for anemia within the population.

Evaluation of the URIT-2900 automated hematology analyzer for screening of thalassemia and hemoglobinopathies in Southeast Asian populations.

BACKGROUND: The effectiveness of the URIT-2900 Hematology Analyzer for screening of hemoglobinopathies commonly found in Southeast Asian populations was examined. METHODS: Appropriate cut-off values of MCV and MCH for screening of α(0) and ß thalassemias were derived from the receiver operator characteristic curve conducted initially on 279 subjects with various thalassemia genotypes. Validation was performed additionally in a cohort of another unrelated 313 subjects. RESULTS: The best cut off values of MCV and MCH were found to be 78fL and 27pg, respectively. Using these cut off values in combination with the dichlorophenolindophenol test in screening of α(0) thalassemia, ß thalassemia and Hb E in a cohort study revealed 100% sensitivity, 79.6% specificity, 80.0% positive predictive value and 100% negative predictive value. CONCLUSION: The combined blood cell counting using the URIT-2900 Automated Hematology Analyzer and dichlorophenolindophenol test is suitable for population screening of thalassemia and hemoglobinopathies in Southeast Asia.

Anemia, iron deficiency and thalassemia among adolescents in Northeast Thailand: results from two independent surveys.

The prevalence of adolescent anemia, iron deficiency and thalassemia were examined in 2 provinces of northeast Thailand. Blood specimens were collected from adolescent subjects aged 15-17 years in 2 areas; 185 (85 males and 100 females) in Mukdahan province and 313 (116 males and 197 females) in Roi-Et. RBC parameters, serum ferritin levels, Hb and DNA analyses for the identification of common thalassemia genes in Thailand were investigated. The prevalences of anemia were found to be 21.1% (8.1 in male and 13.0 in female) and 16.6% (8.9 in male and 7.7 in female) in Mukdahan and Roi-Et province, respectively. Iron deficiency was observed to be 24.3% in Mukdahan and 14.7% in Roi-Et. Various types of thalassemia were identified in 62.2 and 58.8% of the subject populations, respectively. The proportions of iron deficiency, thalassemia and combined thalassemia and iron deficiency among anemic subjects were 10.2, 53.8 and 30.8% in Mukdahan, and 7.7, 67.3 and 9.6% in Roi-Et. Hematological characteristics were analyzed and are presented. It is concluded that thalassemia and hemoglobinopathies rather than iron deficiency are major causes of adolescent anemia which should be taken into account in public health strategies for the control of anemia in the region.