Iron deficiency does not compromise the diagnosis of high HbA(2) β thalassemia trait

Serum Iron and Ferritin Levels in Beta Thalassemia Carriers in Duhok Governorate, Iraq

Background Thalassemia and iron deficiency anemia (IDA) account for most cases of microcytic hypochromic anemia. It is a common misconception that iron deficiency does not occur in thalassemia. However, studies have found that iron deficiency can coexist in carriers of beta thalassemia. Objective The aim of this study was to determine the prevalence of iron deficiency and iron overload in carriers of beta thalassemia in Duhok, Iraq. Patients and methods This prospective cross-sectional study included 250 patients with beta thalassemia carriers attending Kurdistan Private Hospital Laboratory Department from July 2021 to June 2023. Patients with microcytic hypochromic blood picture were tested for HbA2 levels, and those with a level >3.7% were included in the study and were tested for serum iron and serum ferritin levels. Results The age range was 15-80 years, with a mean of 25 years, and the male-to-female ratio was 1.5:1. The prevalence of iron deficiency in beta thalassemia carriers was 16% (N = 40). The prevalence of iron overload was 8.4% (N = 21). There was a significant statistical difference among those with iron deficiency, normal iron status, and iron overload in terms of hemoglobin level (P=0.001), RBC count (P=0.012), HbA2 (P=0.015), and serum ferritin (P < 0.0001). Conclusion Iron deficiency is more prevalent in beta thalassemia carriers than iron overload, necessitating proper assessment of iron status in patients with beta thalassemia carriers. Those with abnormal iron status need effective treatment to optimize the overall outcomes in patients with beta thalassemia carriers.

Unresolved laboratory issues of the heterozygous state of β-thalassemia: a literature review

Although considered a mild clinical condition, many laboratory issues of the carrier state of β-thalassemia remain unresolved. Accurate laboratory screening of β-thalassemia traits is crucial for preventing the birth of a β-thalassemia major child. Identification of carriers in the laboratory is affected by factors that influence red cell indices and HbA2 quantification. Silent mutations and co-inheriting genetic and non-genetic factors affect red cell indices which decreases the effectiveness of the conventional approach. Similarly, the type of β mutation, co-inheriting genetic and non-genetic factors, and technical aspects, including the analytical method used and variations in the HbA2 cut-off values, affect the HbA2 results, leading to further confusion. However, the combination of mean corpuscular volume, mean corpuscular hemoglobin, and hemoglobin analysis increases the diagnostic accuracy. Diagnostic problems arising from non-genetic factors can be eliminated by carefully screening the patient's clinical history. However, issues due to certain genetic factors, such as Krüppel-like factor 1 gene mutations and α triplication still remain unresolved. Each laboratory should determine the population-specific reference ranges and be wary of machine-related variations of HbA2 levels, the prevalence of silent mutations in the community.

Iron interference in hemoglobin production in piglets from birth to weaning

ABSTRACT: Iron deficiency anemia (IDA) in humans is defined as the decrease of total hemoglobin concentration and the non-production of the adult hemoglobin subtype 2 - HbA2 (α2δ2 chains), which is considered a marker of IDA severity in humans, dosed together with the iron serum. This study aimed to determine the standard of hemoglobin types in piglets induced to experimentally IDA in the first 21 days of life (delivery to weaning). In the present study, 40 piglets born from four naïve gilts, were randomly and equally assigned among the gilts. On the third day after delivery, the groups were randomly distributed in different environments (cement and clay floors) and according to the iron supplementation (iron dextran and placebo). Erythrocyte parameters, serum iron, and hemoglobin trait were analyzed at four moments between birth and weaning days. The group of piglets that did not receive iron dextran supplementation on the third-day post-birth and were placed in the pen without soil did not present HbA2 from the seventh day onwards on the agarose electrophoretogram (pH 8.6) and this observation was correlated to decrease of serum iron (ρ: 0.156, p=0.003) when compared to the other groups’ piglets that did not present iron deficiency. In the present study was possible to determine the swine hemoglobin pattern in IDA, since HbA2 was absent in piglets with IDA in comparison to the non-ferropenic groups and the correlation between the reduction of iron levels and the absence of HbA2.

Genetic and non-genetic factors affecting hemoglobin A2 expression in a large cohort of Thai individuals: implication for population screening for thalassemia

OBJECTIVE

Increased hemoglobin (Hb) A₂ level is an important diagnostic marker for β-thalassemia carrier screening. The level of Hb A₂ is also useful for differentiating several thalassemia syndromes. We have examined data bases for reduced Hb A₂ expression in a large cohort of Thai subjects.

METHODS

A study was done on 1,498 subjects with non-thalassemia and various types of thalassemia and Hb variants to determine the effect of thalassemia genotypes and on 103 women of reproductive age to determine the effect of iron deficiency. Hb analysis was done using capillary electrophoresis, and thalassemia genotypes were defined by DNA analysis. Serum ferritin was measured using chemiluminescent microparticle immunoassay.

RESULTS

Subjects were divided into 35 groups based on iron status, Hb, and DNA analysis. Decreased Hb A₂ level was observed in those with Hb Q-Thailand, δ-hemoglobinopathies, δβ⁰-thalassemia, Hb Lepore, iron deficiency, α-thalassemia, and especially Hb Constant Spring (Hb CS). While β-thalassemia carriers with Hb H disease still had elevated Hb A₂ levels, most of the β-thalassemia carriers with Hb H-CS disease had Hb A₂ less than 3.5% as a diagnostic cut-off. The lowest Hb A₂ level was observed in those with Hb H-CS disease.

CONCLUSION

Iron deficiency, Hb CS trait, homozygous Hb CS, and Hb H disease may reduce Hb A₂ level, leading possibly to misdiagnosis of β-thalassemia, especially in carriers with borderline Hb A₂. Hb CS showed the strongest effect on Hb A₂ expression. Understanding the basis for reduced Hb A₂ expression may help reduce the diagnostic pitfalls of β-thalassemia in the region.

Clinical utility of Abbott Alinity hq extended red blood cell parameters in differentiating β-thalassemia trait and iron deficiency anemia

INTRODUCTION

The objective of the study was to evaluate the performance of the Abbott Alinity hq advanced multi angle polarized scatter separation (MAPSS^TM )-based optical RBC technology, for the differentiation between iron deficiency anemia (IDA) and β-thalassemia carrier status.

METHODS

Four hundred and sixty-four samples were analyzed. 228 were healthy controls, 30 were β-thalassemia carriers, and 40 were IDA. Receiver operating characteristics analysis evaluated the performance of red cell parameters and mathematical formulas.

RESULTS

RBC concentration was the most efficient discriminant (area under the curve; AUC of 0.963, Youden Index of 0.88) followed by red blood cell distribution width in size distribution (AUC of 0.960 and YI of 0.86), and red blood cell distribution width coefficient of variation (AUC of 0.924, and YI of 0.74). The absolute reticulocyte concentration showed good diagnostic efficiency, with AUC of 0.808. Hemoglobin distribution width, the %CV of directly measured cellular hemoglobin concentration, and CHCr, the average hemoglobin concentration of reticulocytes have emerged as novel discriminating parameters, with AUC of 0.749 and 0.785, respectively. The England and Fraser index was the best discriminating mathematical formula based on Youden Index of 0.91. The Ricerca, red blood cell distribution width index, Green and King, and Mentzner Index formulas also showed strong discriminative power. The Shine and Lal index, together with the recent mathematical formula M/H, (ratio of percent microcytic and hypochromic red blood cells) demonstrated moderate performance with AUC of 0.796 and 0.740, respectively.

CONCLUSION

Extended red cell analysis delivered by the advanced optical technology on the Alinity hq hematology analyzer has efficient diagnostic utility in the initial discrimination of the two most common microcytic anemias: IDA and β-thalassemia trait.

Borderline HbA2 levels: Dilemma in diagnosis of beta-thalassemia carriers

There is inconsistency in the exact definition of diagnostic levels of HbA₂ for β thalassemia trait. While many laboratories consider HbA₂ ≥4.0 % diagnostic, still others consider HbA₂ ≥3.3 % or HbA₂ ≥3.5 % as the cut-off for establishing β thalassemia carrier diagnosis. This is because, over the years, studies have described β thalassemia carriers showing HbA₂ levels that lie above the normal range of HbA₂ but below the typical carrier range of β thalassemia. These, "borderline HbA₂ levels", though not detrimental to health, are significant in β thalassemia carrier diagnosis because they can lead to misinterpretation of results. In this review, we have evaluated the prevalence of borderline HbA₂ levels and discussed the causes of borderline HbA₂ values. We have also compiled an extensive catalogue of β globin gene defects associated with borderline HbA₂ levels and have discussed strategies to avoid misdiagnosing borderline HbA₂ β thalassemia carriers. Our analysis of studies that have delineated the cause of borderline HbA₂ levels in different populations shows that 35.4 % [626/1766] of all individuals with borderline HbA₂ levels carry a molecular defect. Among the positive samples, 17 % [299/1766] show β globin gene defects, 7.7 % [137/1766] show α thalassemia defects, 2.7 % [49/1766] show KLF1 gene mutations, 2.3 % [41/1766] show the co-inheritance of β and α thalassemia, 2.0 % [37/1766] show the co-inheritance of β and δ thalassemia and 1.8 % [32/1766] show α globin gene triplication. It appears that a comprehensive molecular work up of the β globin gene is the only definite method to detect borderline HbA₂ β thalassemia carriers, especially in populations with a high prevalence of the disease. The presence of associated genetic or acquired determinants may subsequently be assessed to identify the cause of borderline HbA₂.

Development of a High Resolution Melting Curve Analysis for the Detection of Hemoglobin δ-Chain Variants in Thailand and Identification of Hb A2-Walsgrave [codon 52 (GAT>CAT), Asp→His; HBD:c.157G>C] in a Pregnant Woman from Southern Thailand

Background: Delta-chain (δ-chain) variants are a group of rare hemoglobin (Hb) variants resulting from mutations within the δ-globin gene. Although quantification of Hb A2 levels is a useful screening tool for the beta-thalassemia trait, the coinheritance of a δ-globin gene mutation can lead to misinterpretation of diagnostic results. Objective: To identify an unreported Hb A2 variant in Thailand and to develop a high resolution melting (HRM) curve assay for the four δ-globin chain variants found in the Thai population. Materials and Methods: Allele-specific polymerase chain reaction (ASPCR) was used to analyze a total of 18 DNA samples for Hb variants comprising 10 wild-type controls, 4 Hb A2-Melbourne, 1 Hb A2-Lampang, 2 Hb A2-Kiriwong, and an unknown variant via HRM assays. Results: The unreported Hb A2 variant in Thailand was found to be Hb A2-Walsgrave resulting from δ-globin gene mutation at codon 52 (GAT>CAT). This was also confirmed using ASPCR. In addition, we demonstrated that the HRM curve profile for Hb A2-Melbourne, Hb A2-Lampang, Hb A2-Walsgrave, and Hb A2-Kiriwong could be identified so as to distinguish the mutant alleles from one another and from wild-type alleles. Conclusion: This HRM assay detected both known and unknown mutations with simultaneous differentiation between heterozygous and homozygous alleles on a polymerase chain reaction fragment spanning four of the δ-globin variants found in Thailand. This assay may help to support the prevention and control of thalassemias and hemoglobinopathies in Thailand.

Twelve Cases of Hb Manitoba [α102(G9)Ser→Arg]: the Fluctuation in the Variant Expression

Hb Manitoba [α102(G9)Ser→Arg] is a rare α chain variant with diverse ethnic origins. It is mildly unstable with an expression of around 10.0-14.2% in the heterozygous state in most literature. In this study, 12 cases of Hb Manitoba [11 cases carried Hb Manitoba II (HBA1: c.309C>A) and one case carried Hb Manitoba IV (HBA1: c.307A>C)] were detected during a wide-spectrum study of α chain variants in the UK. Fluctuation in variant expression from 6.9 to 15.2% of total Hb on high performance liquid chromatography (HPLC) would pose a diagnostic dilemma in routine laboratories. Focusing on the variant expression, the median of Hb Manitoba was around 11.5% of total Hb in three cases, apparently with normal hemoglobin (Hb), and normal red blood cell (RBC) indices. Two cases showed a higher expression (13.9 and 15.2%) and five cases showed a lower expression (6.9-9.9%). The common α-thalassemia (α-thal) -α^3.7 (rightward) deletion coexisted with one case of increased Hb Manitoba expression. Iron (or other nutrient) deficiency was likely the cause of decreased Hb Manitoba percentage in this study. The α73(EF2)Val→Val (α2) (HBA2: c.222G>T) polymorphism is published for the first time and coexisted with two cases. The Cap +14 (C>G) (HBA2: c.-24C>G) polymorphism coexisted with another case in a heterozygous state. In conclusion, the fluctuation in variant expression can cause a diagnostic dilemma, especially in routine laboratories. Screening for the common -α^3.7 deletion and iron deficiency is recommended when an α chain variant is suspected.

A Chinese Male with Normal Hematological Indices and High Hb A2 Levels in β-Thalassemia Trait

β-Thalassemia (β-thal) is a common hematological disorder in the Guangxi Zhuang Autonomous Region of Southern China. Heterozygous β-thal is usually associated with reduced hematological indices and increased Hb A₂ levels. However, the preventive program of the regional government only conducts the screening of hematological indices [complete blood count (CBC)] especially at primary hospitals. In this study, we describe a male β-thal patient presenting normal hematological indices but with a high Hb A₂ level. We proposed that hemoglobin (Hb) analysis and CBC should be performed together in the preventive screening program in regions with a high thalassemia incidence to avoid misdiagnosis.

Evaluation of Thalassaemia Screening Tests in the Antenatal and Non-Antenatal Populations in Singapore

Introduction: Haemoglobinopathy testing is performed for carrier screening and evaluation of microcytic anaemia. We evaluated the effectiveness of thalassaemia screening tests at our institution and suggest ways of improving the testing algorithm. Materials and Methods: A total of 10,084 non-antenatal and 11,364 antenatal samples with alkaline gel electrophoresis (AGE), capillary electrophoresis (CE), haemoglobin H (HbH) inclusion test, mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV) were retrospectively reviewed. A subgroup of 187 samples with genetic testing was correlated with HbH inclusions and MCH/MCV. The effect of iron deficiency on percentage haemoglobin A2 (HbA2) was studied. Results: HbH inclusion test showed low sensitivity of 21.43% for α-thalassaemia mutations but higher sensitivity of 78.95% for --SEA deletion. Byreceiver operating characteristic (ROC) analysis, MCH ≤28 pg or MCV ≤80 fl for non-antenatal samples and MCH ≤27 pg or MCV ≤81 fl for antenatal samples had >98% sensitivity for HbH inclusions. Above these thresholds, the probability that HbH inclusions would be absent was >99% (negative predictive value [NPV] >99%). MCH ≤28 pg had 100% sensitivity (95% CI 95.63%-100%) for α-thalassaemia mutations and 97.68% calculated NPV in the antenatal population. Detection of haemoglobin variants by CE correlated highly with AGE (99.89% sensitivity, 100% specificity). Severe iron deficiency reduced HbA2 in haemoglobin E (P <0.001) and α-thalassaemia (P = 0.0035), but not in β-thalassaemia. Conclusion: MCH/MCV thresholds have adequate sensitivity for α-thalassaemia in the antenatal population, and genotyping plays an important role as HbH inclusion test shows low sensitivity. CE without AGE, may be used as initial screening for haemoglobin variants. Our study provides contemporary data to guide thalassaemia screening algorithms in Singapore. Key words: Haemoglobinopathy, Mean corpuscular haemoglobin, Mean corpuscular volume

Hemoglobin A2 (HbA2) has a measure of unreliability in diagnosing β-thalassemia trait (β-TT)

INTRODUCTION

Detection of β-thalassemia trait or carriers (β-TT) depends significantly on an increase in Hemoglobin A₂ (HbA₂) levels, which is found at low levels (<3%) in normal healthy individuals and elevated levels (≥3.5%) in β-TT individuals. The study was designed to evaluate the reliability of the diagnostic parameter HbA₂ in the differentiation of β-TT and non-β-TT in Saudis.

METHODS

The widely used high performance liquid chromatography (Variant II Bio-Rad) was used to measure HbA₂ levels in blood. Sanger sequencing was used to screen the variation in globin genes (HBB, HBD, HBA1, and HBA2). All the study subjects were divided into βTT and non-βTT (wild) categories based on the presence or absence of HBB variations and further sub-divided into false positive, true positive, false negative, and true negative, based on HbA₂ values.

RESULTS

Out of 288 samples, 96 had HBB gene mutations. Of the 96 β-TT samples, sickle cell trait (SCT) samples (n = 58) were excluded, while the remaining (38 β-TT) were included in the detailed analysis: seven subjects with the HBB mutation had normal HbA₂ (<3%), and three were borderline (3.1-3.9%). The remainder (n = 28) had an elevated HbA₂ level (>4%). Based on HbA₂ analysis alone, both these groups would be incorrectly diagnosed as normal. Similarly, of the 189 non-β-TT samples, 179 had normal HbA₂, eight had borderline HbA₂, and two had a HbA₂ level above 4%. Based on HbA₂ analysis alone, borderline and >4% HbA₂ individuals, negative for β-TT, can be incorrectly diagnosed as carriers.

CONCLUSION

Given the percentage of samples falling in the HbA₂ "borderline" and "normal" categories, it can be concluded that HbA₂ has a measure of unreliability in the diagnosis of β-thalassemia carriers.

Unusual Anemias

Many processes lead to anemia. This review covers anemias that are less commonly encountered in the United States. These anemias include hemoglobin defects like thalassemia, bone marrow failure syndromes like aplastic anemia and pure red cell aplasia, and hemolytic processes such as paroxysmal nocturnal hemoglobinuria. The pathogenesis, diagnostic workup, and treatment of these rare anemias are reviewed.

Evaluation of Anemia

Anemia is a common problem in primary care. Classification based on mean cell volume narrows the differential diagnosis and directs testing. A marked macrocytosis is characteristic of vitamin B12 and folate deficiencies, certain medications, and primary bone marrow disorders. The three most common causes of microcytic anemia are iron deficiency, thalassemia trait, and anemia of inflammation. Additional laboratory testing is required for diagnosis. Determination of the rate of development of anemia and examination of a blood smear may provide diagnostic clues to guide more specialized testing. Diagnosis of iron, vitamin B12, or folate deficiency mandates determination of the underlying cause.

Hemoglobin Analysis in the First Year of Life

BACKGROUND AND OBJECTIVES

In newborns and infants during their first year of life, there is a dynamic change in the fraction of hemoglobin (Hb). To apply Hb analysis as a phenotypic diagnosis of thalassemia in newborns and infants, we need normal values of each Hb fraction for reference.

METHODS

Seventeen cord bloods from normal deliveries were collected for analysis. One hundred and thirty-seven infants from the pediatric outpatient clinic were recruited and were categorized by their ages into a series of short periods (month±2 weeks). Both alpha and beta thalassemia carriers detected were excluded. Samples with an Hb level less than 10.0 g/dL were also excluded. The proportion of Hb A (α2β2), A2 (α2δ2), and F (α2γ2) was obtained from high-performance liquid chromatography and analyzed according to its categorized periods.

RESULTS

There were 90 (58.4%) specimens left for evaluation. The percentage of Hb A, A2, and F gradually changed with increasing age. The percentage of Hb A was 21.14±7.04% (mean±SD) in cord blood and increased substantially to 83.38±1.31% at the sixth month. The level was sustained thereafter. The incremental pattern of Hb A2 was similar to Hb A. The value was 0.32±0.19% at the beginning and reached a plateau with 2.78±0.25% at the sixth month. The percentage of Hb F started at 78.39±7.59% in cord blood and decreased rapidly in the first 6 months.

CONCLUSIONS

The data possibly can be applied as quick guidance for interpretation of Hb analysis in newborns and infants during their first year of life.

Incidence of haemoglobinopathies in Sicily: the impact of screening and prenatal diagnosis

BACKGROUND

Haemoglobinopathies are a major public health problem in Sicily: it was estimated a frequency of 1/245 couples are at risk of haemoglobinopathies. This paper reviews legislative actions, prevention activities, carrier screening, genetic counselling, foetal sampling and laboratory methodology analysis evolution reporting the results of 30 years of prevention actions to assess the efficiency of our preventative programme in the control of haemoglobinopathies in Sicily.

METHODS

This programme consisted principally of five phases: legislative actions, public awareness campaign, carrier screening, genetic counselling and prenatal diagnosis.

RESULTS

These programmes have been very effective, which we can see from a greater public awareness of thalassaemia and its prevention in the target population furthermore by a marked decline in the incidence of thalassaemia major and sickle cell anaemia from 1 in 245 live births in the absence of prevention to 1 in 2000, with a reduction in about 85%. The residual cases were because of a conscious choice by expecting parents in relation to improved life expectancy as well as improved quality of life of the affected patients.

CONCLUSION

The study suggests that public health authorities should act and invest in a similar programme for prevention of thalassaemia, as well as in relation to the increased survival of patients and the consequent organ complications.

Antenatal haemoglobinopathy screening: Patterns within a large obstetric service. Working towards a standard of care

BACKGROUND

Antenatal screening can predict clinically significant haemoglobinopathies, however in Australia, practices are not standardised and are evolving as the population becomes more ethnically diverse. This study describes antenatal screening practices in a large Australian laboratory/antenatal service.

METHODS

Data were collected retrospectively on consecutive antenatal haemoglobin electrophoresis over 16 months and correlated with obstetric data, obtained from the local obstetric database.

RESULTS

462 patients were included, with an average gestation of 25.8 weeks. 'Pregnancy' was the most common stated indication, with absent indication/clinical information in 8%. Gestational age was documented in 54%. In 15%, no contact details of the referrer were documented and partner screening was traceable in only 25 cases (5.4%). In 82% of cases, no abnormalities were detected. Beta thalassemia trait was the most common positive result. Only 52% of patients had recent iron studies. The mean haemoglobin was 111.6 g/L and mean cell volume was 80.5 fl at the time of testing. Ethnicity was documented on the request form in 3%. After Australasia, the most common ethnicity of patients was South East Asia and the Middle East.

CONCLUSION

Referral patterns in our health service are diverse and reflect our changing population and care practices. Detailed guidelines are required and we propose a comprehensive algorithm for general use where selective screening is practiced within an Australasian population or one with similar demographics.

Screening for thalassemia carriers in populations with a high rate of iron deficiency: revisiting the applicability of the Mentzer Index and the effect of iron deficiency on Hb A2 levels

Differentiating between β-thalassemia (β-thal) minor and iron deficiency has important implications in thalassemia carrier screening. Several complete blood count (CBC)-based equations have been proposed for differentiating these two conditions. The applicability of these equations in populations with high rates of iron deficiency and β-thal minor, where patients can have both conditions, is limited. In addition, there have been conflicting reports on the possible effect of iron deficiency on Hb A2 level with possible consequences for thalassemia screening programs. Here, we demonstrate that in our population the Mentzer Index separates individuals with β-thal minor from those without β-thal minor, regardless of their iron status. Iron deficiency also does not reduce Hb A2 levels in β-thal minor patients. Correction of iron deficiency is not required for diagnosis of β-thal minor using high performance liquid chromatography (HPLC).

Detection of Abnormal Hemoglobin Variants by HPLC Method: Common Problems with Suggested Solutions

Thalassemia and thalassemic hemoglobinopathies pose serious health problem leading to severe morbidity and mortality in Indian population. Plethora of hemoglobin variants is prevalent in multiethnic Indian population. The aim of the present study was to analyze laboratory aspects, namely, hematological profile and HPLC findings of the hemoglobin variants detected, and to discuss problems that we faced in diagnosis in a routine clinical laboratory. We screened a total of 4800 cases in a hospital based population of North India in a 2-years period of by automated HPLC method using the Variant Hemoglobin Testing System (Variant II Beta Thalassemia Short Program, Bio-Rad Laboratories) under the experimental conditions specified by the manufacturer. Whole blood in EDTA was used and red cell indices were determined using automated hematology analyzer. We detected 290 cases with abnormal variants in which beta thalassemia was the most common followed by hemoglobin E. Here, we discuss the laboratory aspects of various hemoglobin disorders and diagnostic difficulties in cases like borderline HbA2 values, presence of silent mutation, alpha thalassemia gene, and few rare variants which at times require correlation with genetic study. Special attention was given to HbA2 level even in presence of a structural variant to rule out coinheritance of beta thalassemia gene.

Impact of iron deficiency on hemoglobin A2% in obligate β-thalassemia heterozygotes

INTRODUCTION

The potential impact of concomitant iron deficiency on hemoglobin A2 (HbA2)-based identification of β-thalassemia trait (βTT) is a worrisome issue for screening laboratories. This is especially true for resource-constrained settings where iron deficiency is widespread and molecular confirmatory tests for borderline low HbA2 values may be unavailable.

METHODS

Obligate βTT carrier individuals (n = 752) were identified during screening studies on the parents of thalassemia major patients. HbA2%, complete blood counts and serum iron, ferritin and transferrin saturation were studied. Iron-deficient individuals (n = 135) with normal range HbA2% were taken as controls.

RESULTS

Concomitant iron deficiency (defined as ferritin ≤15 ng/mL and/or transferrin saturation ≤15%) was present in 20.7% (156/752) βTT cases, that is, 33.3% females (122/366) and 8.8% males with βTT (34/386). Mean HbA2 in iron-replete βTT was 5.4 ± 0.8 (range 3.1-7.9) and in iron-deficient βTT was 5.4 ± 0.9 (range 3.3-7.6). HbA2 < 4.0% was found in 23/752 (3.1%) βTT: 13/595 iron-replete (2.2%) and 10/157 (6.4%) iron-deficient βTT individuals. However, five of the 10 iron-deficient βTT cases carried the silent CAP+1 (A>C) β-thalassemia allele accounting for the borderline HbA2%. On a separate analysis, all five severely anemic βTT (Hb < 80 g/L) and 16/17 βTT with severe hypoferritinemia (<5 ng/mL) had HbA2 > 4.5%. The single case with serum ferritin 4.8 ng/mL and HbA2 3.3% showed a CAP+1 (A>C) mutation.

CONCLUSIONS

Iron deficiency was prevalent among north Indian βTT individuals, especially women. After adjusting for other causes of low HbA2 in βTT, iron deficiency, even when very severe, was very unlikely to interfere significantly with HbA2-based identification of βTT.

Coexisting iron deficiency anemia and Beta thalassemia trait: effect of iron therapy on red cell parameters and hemoglobin subtypes

Background. Coexistence of iron deficiency anemia (IDA) and beta thalassemia trait (BTT) has been the topic of few studies. However, no study from our country was found evaluating the effect of iron therapy in patients with concomitant IDA and BTT. Methods. Over a period of two years, 30 patients with concomitant IDA and BTT were included. All the patients had a complete blood count, serum iron studies, and thalassemia screening using BIORADTM hemoglobin testing system. The patients received oral iron therapy in appropriate dosages for a period of twenty weeks, after which all the investigations were repeated. Appropriate statistical methods were applied for comparison of pre- and posttherapy data. Results. All except two patients were adults with a marked female preponderance. Oral iron therapy led to statistically significant improvement in hemoglobin, red cell indices (P < 0.05), and marked change in serum iron, ferritin, and HbA2 levels (P < 0.001). There was a significant reduction in the total iron binding capacity levels. Conclusion. The present study shows the frequent occurrence of iron deficiency anemia in patients with beta thalassemia trait, which can potentially confound the diagnosis of the latter. Hence, iron deficiency should be identified and rectified in patients with suspicion of beta thalassemia trait.

Incidence of β-thalassemia carrier on 1495 couples in preconceptional period

OBJECTIVE

This research, conducted on 1495 couples in preconceptional period, demonstrates how the study of globular resistance of erythrocytes (GRO) is not a first choice test and not useful as other more accurate tests to identify subjects with β-thalassemia trait. Instead, the complete blood count (CBC) and the evaluation of HbA, HbA2 and HbF by high pressure liquid chromatography (HPLC) are essential.

METHODS

Each couple arrived in our laboratory to screen for β thalassemia. In case of patients with positive (240) or doubtful (112) results, we studied β-globin gene.

RESULTS

Of the 2990 subjects examined, we found 280 subjects with β-thalassemia trait (9.36%). During biochemical tests, among 112 subjects with doubtful--normal GRO or altered GRO--results, 40 of them resulted positive for the molecular analysis, while 72 of them did not show mutations in β-globin genes. The 2710 samples with non-carriers of β-thalassemia trait presented as mean evaluation of HbA2 2.6%, while the 280 subjects with β-thalassemia trait presented as mean evaluation of HbA2 4.8%. Molecular study showed that the β thalassemia phenotype is caused by a small number of mutations, whose regional distribution is typical.

CONCLUSIONS

In the presence of thalassemic parameters in the CBC, the accurate and precise quantification of hemoglobin HbA2 is essential for the diagnosis of β-thalassemia trait. DNA mutation analysis provides the most effective way to detect primary gene mutations. The mutations identified in this work can be identified with a simple and inexpensive kit. This means, in economic terms, a significant savings for health spending.