Screening For Hemoglobinopathies Research Articles

Use of HbA2 As a Discriminator for S/Beta Thalassaemia in a Nigerian Setting,

Abstract 4206An integral part of an EU-UNDP funded pilot sickle cell screening project, was the installation, in Abuja (Federal Capital Territory) Nigeria, June 2010, of a High Performance Liquid Chromatography (HPLC) instrument. Prior to the installation, haemoglobinopathy screening was carried out using only unstained paper electrophoresis. Minor bands were difficult to visualise and the proportions of haemoglobins were not measured. Full blood count (FBC) data was also not routinely available. Therefore awareness of both alpha and beta thalassaemia was low as was the implications of coinheritance of beta thalassaemia with haemoglobin (Hb) S.Stratified community surveys were carried out with samples collected as Guthrie card blood spots; children aged less than 6 months, and whole blood; children aged between 6 months and 5 years. Blood spot samples were analysed using newborn sickle cell screening reagents and whole blood samples using beta thalassaemia short reagents, the later allowing accurate Hb A2 and Hb F measurement. Samples were processed on a Biorad™ Classic (instrument and reagents, Biorad, Hercules, CA.). Reporting algorithms were defined for both reagent sets. Using the beta thalassaemia reagents, Hb S/beta thalassaemia was considered when Hb S was predominant, Hb A absent or significantly reduced and the Hb A2>5.Over 10,000 samples were analysed, 410 had sickle cell disease, of which 370 were transported to London for further analysis, 70 of these had an Hb A2>5%, mean and range 5.9(5.1 – 9.1)%. To validate the algorithm 31 samples (Hb A2 3.5 – 7.4%), were selected for beta gene sequencing (Mai et al, 2004) and/or PCR analysis for the 7 common alpha gene deletions (3.7kb, 4.2kb, SEA, MED, THAI, FILL, 20.5kb and triplicated alpha gene locus, anti 3.7kb), (Chong et al, 2000, Wang et al, 2003). Five samples had an Hb A2of 3.5 – 4.9%, 2 with Hb A present (23 and 25%), all were Hb SS, 4 negative for alpha thalassaemia deletions and 1 heterozygous for the alpha 3.7kb deletion. Sixteen samples had an Hb A2 of 5.0 – 5.9%, all were Hb SS, 5 negative for alpha thalassaemia deletions and 11 heterozygous for the alpha 3.7kb deletion. Seven samples had an Hb A2 of 6.0 – 6.9%, 6 were Hb SS, 1 negative for alpha thalassaemia deletions, 1 heterozygous and 4 homozygous for the alpha 3.7kb deletion. One, Hb A2 6.9%, was a compound heterozygote for Hb S/ beta zero codon 106/107(+G) mutation. Three samples had an Hb A2 of 7.0 – 7.4%, review of chromatograms indicated that all showed poor chromatography due to lack of separation between Hb A2 and Hb S or shoulders to the left of the Hb A2 peak. All were Hb SS and heterozygous for the alpha 3.7kb deletion, with 1 also positive for the triplicated alpha globin gene, anti 3.7kb. Four other samples with Hb A2 >7% also showed poor chromatography, but were insufficient for molecular testing.The results indicate that Hb A2values >5% were mainly due to co-existing alpha thalassaemia with 76% of those tested, positive for the 3.7kb deletion. Poor chromatography was also a contributor particularly at the higher Hb A2 levels. During the initial stages of the project air conditioning failure caused major temperature fluctuations on overnight runs, this problem was resolved, improving chromatography. One case of S/beta zero thalassaemia was detected confirming the presence in this population. The results suggest that the Hb A2 may be considered as a discriminator for S/beta thalassaemia screening in this setting, increasing the algorithm Hb A2 level to >6.0% may improve specificity and reduce the number of false positives, this warrants further investigation. Future aims of the project for children over 6 months of age, include initiating routine FBC analysis and testing parental samples as a cost effective means of confirming suspected cases. Disclosures:No relevant conflicts of interest to declare.

Diagnostic Utility of Isoelectric Focusing and High Performance Liquid Chromatography in Fetal Cord Blood Screening for Thalassemia and Non-Sickling Hemoglobinopathies,

Abstract 4202 Background:Thalassemia and non-sickling hemoglobinopathies are highly prevalent in Southeast Asia. High performance liquid chromatography (HPLC), β-thalassemia short program, is the most common technique routinely used in this region, while IEF is rarely employed. However, HPLC, β-thalassemia short program, cannnot quantify HbBart’s, as well as HbH. In addition, the acetylated HbF, which is frequently found in cord blood, interferes with the HbBart’s and HbH peaks on HPLC. We primarily aim to compare diagnostic utilities of IEF and HPLC in fetal cord blood screening for prenatal diagnosis of thalassemia and non-sickling hemoglobinopathies in Thailand. Methods:One-hundred and two cord bloods from the National Cord Blood Bank and fetuses of high risk couples were analyzed using IEF and HPLC, β-thalassemia short program, and correlated with red cell indices and DNA analyses. HbBart’s was quantified only on the IEF method. The sensitivity and specificity to screen for α-globin and β-globin gene mutations were determined. Results:Of 88 cases showing HbBart’s on hemoglobin analysis, IEF yielded 98.9% sensitivity to identify at least one α-globin gene defect (−α−3.7, -α−4.2, -αCS, -αPS, –SEA, –Thai, -α−3.7/-α−3.7 and -α−3.7/-αCS), while HPLC yielded only 83.7% sensitivity to detect at least one α-globin gene defect. All missing cases on HPLC were single α-globin gene deletion that had HbBart’s less than 1.5% of total hemoglobin measured on IEF. Hb Constant Spring (CS) and Hb Pakse (PS) heterozygotes (N = 11) had small amount of HbBart’s less than 3%, but neither HbCS nor HbPS was detectable on both tests. HbBart’s ≥ 2% yielded 100% sensitivity to identify two α-globin gene defects, while HbBart’s ≥ 3% yielded 100% specificity to diagnose two α-globin gene defects. MCV and MCH are the most helpful red cell parameter in screening for α-thalassemia. MCV ≤ 95 fL yielded 100% sensitivity to identify two α-globin gene deletions, while MCV ≤ 90 fL yielded 100% specificity to identify two α-globin gene deletions. In addition, MCH ≤ 30 pg yielded 100% sensitivity and 100% specificity to identify two α-globin gene deletions.Thirty two cord bloods showed HbA2/E, ranging from 1.9–15.6%. DNA analysis using a reverse dot blot technique for detecting common β-thalassemia mutations in Thailand demonstrated HbE mutation in all cases, while no β-thalassemia mutations were identified. Therefore, detectable HbA2 in cord blood usually represents HbE, not HbA2. Three HbE heterozygotes with two α-globin gene deletions demonstrated high HbBart’s and low MCV, as well as low MCH, similar to those with two α-globin gene deletions alone. On the other hand, HbE heterozygotes with single α-globin gene defects could not be differentiated from pure HbE heterozygotes. Conclusion:IEF is superior to HPLC β-short program in screening for α-globin gene defects in prenatal cord blood analysis. The amount of HbBart’s, MCV and MCH are helpful for identifying α-thalassemia. The presence of HbA2 in cord blood indicates HbE mutation, but not β-thalassemia. Disclosures:Sutcharitchan:Novartis: Research Funding.

Hemoglobinopathy Newborn Screening Knowledge of Physicians

Hawai'i has a diverse population, including many individuals of Asian descent. A relatively high proportion of Hawai'i infants are born with inherited hemoglobinopathies; about 2% have α-thalassemia trait. The Hawai'i Genetics Program engages in genetics services and public health activities, including a hemoglobinopathy clinic and provider education. This study was undertaken to assess baseline pediatrician hemoglobinopathy knowledge that would then inform the development of education programs. In 2008-2009, a brief survey assessed Hawai'i pediatrician hemoglobinopathy and newborn screening (NBS) knowledge. To place results in context, pediatricians in San Francisco (SF) and Salt Lake City (SLC) (similar and different patient demographics, respectively) were surveyed; 660 surveys were mailed to pediatricians from the NBS Program database (Hawai'i) or telephone listings (SF and SLC). Results were analyzed in 2011. Total and individual knowledge scores were calculated based on four questions. Overall, 226 (34%) pediatricians responded: 113 from Hawai'i, 54 from SF, and 59 from SLC (45%, 23%, and 34% response rates, respectively). Overall, 89.4% of participants had either good or perfect knowledge scores: 16% of participants had attended a hemoglobinopathy educational session in the past 6 months; 32.4% give iron to all anemic patients; 29% reported that β-thalassemia is not detected by NBS, and 8% were unsure. Results identified significant knowledge differences regarding sickle cell disease and whether or not a complete blood count diagnoses α-thalassemia. Knowledge gaps between and within the pediatrician populations present opportunities for education regarding hemoglobinopathies and NBS panels. The results will inform the development of hemoglobinopathy education materials to assure a knowledgeable healthcare workforce in the growing area of genetics and newborn screening.

Practical Diagnosis of Red Cell Disorders in Southern Spain

Background: Hereditary red cell disorders are associated with a protective effect against malaria, which results in an increased prevalence in malaria-endemic areas. Migratory flows from these areas are resulting in a marked increase in such abnormalities in Southern Spain. Methods: All hemoglobin disorders diagnosed between 1997 and 2010 have been recorded. Since 2008, we have performed systematic screening for hemoglobinopathies on African patients. A high-pressure liquid chromatography system was used as screening method for structural hemoglobinopathies and for separation of hemoglobin (Hb) F and A₂. Results: We detected 666 cases in patients of foreign origin and 308 in native Spanish patients. Thalassemias (thal) are the most frequent disorders amongst the local population: β-thal minor, 57.1% (176/308); α-thal, 18.2% (56/308), and δβ-thal, 7.8% (24/308). In ethnic minorities, there is a huge variety of hemoglobinopathies: heterozygous Hb S, 45% (300/666); heterozygous Hb C, 15% (100/666); β-thal minor, 13.7% (91/666); α-thal, 10.2% (68/666); Hb SS in 14 patients, and Hb CC in 9 patients. Of the native patients, 14 were found to have Hb AS and 9 Hb AC. Conclusion: Given the modern migratory flows, greater knowledge of these disorders is needed by all medical staff, and new practical and cost/time-effective diagnostic approaches have to be devised.

Screening for sickle cell and thalassaemia in primary care: a cost-effectiveness study

Haemoglobinopathies, including sickle cell disease and thalassaemia (SCT), are inherited disorders of haemoglobin. Antenatal screening for SCT rarely occurs before 10 weeks of pregnancy. To explore the cost-effectiveness of offering SCT screening in a primary care setting, during the pregnancy confirmation visit. A model-based cost-effectiveness analysis of inner-city areas with a high proportion of residents from ethnic minority groups. Comparison was made of three SCT screening approaches: 'primary care parallel' (primary care screening with test offered to mother and father together); 'primary care sequential (primary care screening with test offered to the mother and then the father only if the mother is a carrier); and 'midwife care' (sequential screening at the first midwife consultation). The model was populated with data from the SHIFT (Screening for Haemoglobinopathies In First Trimester) trial and other sources. Compared to midwife care, primary care sequential had a higher NHS cost of £34,000 per 10,000 pregnancies (95% confidence interval [CI] = £15,000 to £51,000) and an increase of 2623 women screened (95% CI: 1359 to 4495), giving a cost per additional woman screened by 10 weeks of £13. Primary care parallel was dominated by primary care sequential, with both higher costs and fewer women screened. The policy judgement is whether an earlier opportunity for informed reproductive choice has a value of at least £13. Further work is required to understand the value attached to earlier informed reproductive choices.

Comparison of Capillary Electrophoresis with Cellulose Acetate Electrophoresis for the Screening of Hemoglobinopathies

Backgroundβ-thalassemia is primarily found in individuals of Mediterranean and Southeast Asian ancestry. With rapid growth in the Southeast Asian segments of the Korean population, the geographic distribution of hemoglobinopathies is expected to become significantly different from what it is today. In this study, Hb fractions were measured in patients with hypochromic microcytosis to detect thalassemia and Hb variants. To evaluate the feasibility of replacing cellulose acetate electrophoresis (CA) with capillary electrophoresis (CE) in a clinical laboratory, both techniques were performed and the outcomes were compared.MethodsTo evaluate hemoglobinopathies, complete blood cell counts (CBC), CA, and CE were carried out on samples from healthy and microcytic hypochromic groups. The microcytic hypochromic group consisted of 103 patients whose mean corpuscular volume (MCV) was less than 75 fL and mean corpuscular hemoglobin (MCH) was less than 24 pg. Quantitative analysis of Hb fractions was performed on 143 whole blood samples.ResultsThere was a good correlation for measurements of HbA (r=0.9370, P<0.0001), HbA2 (r=0.8973 P<0.0001), and HbF (r= 0.8010, P=0.0304) between the two methods. In the microcytic hypochromic group, there were 29 cases (28.2%) with decreased HbA2, 2 cases (1.9%) with increased HbA2, 3 cases (2.9%) with increased HbF, and 2 cases (1.9%) with increased HbA2 and HbF.ConclusionsCE is comparable to CA for reliable measurement of Hb fractions. It is suitable for screening of hemoglobinopathies in many clinical laboratories.

Newborn Screening for Hemoglobin Disorders

The epidemiology of hemoglobinopathies in the United States reflects recent changes in the demographic make-up of the country’s population. The incidence of thalassemias, in particular, has risen in parallel with immigration of high-risk populations. With an increase in Asian immigration by 2000% in the past three decades, hemoglobinopathies such as Hb H (β4) and Hb E-β-thalassemia (β-thal) have acquired proportionally greater clinical significance in several states, including California. Newborn screening (NBS) for hemoglobinopathies allows for the identification of affected individuals so that prophylactic treatment and comprehensive care may be provided prior to the development of clinical complications. Although the more common hemoglobin (Hb) variants, such as Hb S or Hb C, are readily identified by NBS programs, other clinically significant Hb disorders often remain unresolved or are not reported by NBS programs.The state of California mandates NBS and follow-up for thalassemic disorders as well as sickle cell disease. A centralized laboratory for diagnostic testing and rapid reporting of NBS results is a necessary component of a comprehensive NBS program. Confirmatory diagnostic testing for the California NBS program is provided by the Hemoglobinopathy Reference Laboratory at Children’s Hospital & Research Center Oakland (CHRCO), Oakland, CA, USA. Using electrophoresis, high performance liquid chromatography (HPLC) and DNA-based methods, the laboratory annually performs diagnostic testing for sickle cell disease, β-thal and Hb H disease on more than 1,000 samples. While most screening results are straightforward, 5% of newborns identified with a presumptive hemoglobinopathy by primary screening are modified after confirmatory testing. The availability of rapid and reliable genotyping assays to complement traditional protein chemistry methods for hemoglobinopathy screening has facilitated the diagnosis of thalassemias and sickling disorders in newborns with ambiguous screening results. Together with coordinated follow-up systems in place, the Hemoglobinopathy Reference Laboratory has contributed to the success of the NBS program in the rapid identification and delivery of care to newborns with clinically significant Hb disorders.

Incomplete Follow-up of Hemoglobinopathy Carriers Identified by Newborn Screening Despite Reporting in Electronic Medical Records

ObjectiveHas the recent availability of newborn hemoglobinopathy screening results within patient electronic medical records (EMR) of birth hospitals facilitated follow-up by primary care pediatric providers? MethodsAn online survey of all 137 primary care pediatric providers at a New York City academic medical center was conducted in 2008-2009 to assess practices for hemoglobinopathy trait follow-up. Physicians were resurveyed 1 year later, following educational outreach and a letter of instruction underscoring the availability of screening results in the EMR. All 62 primary care pediatricians were surveyed at a nearby city hospital for comparison. ResultsOverall response rate for the initial survey at the teaching hospital was 58% for pediatricians (N = 57) and family physicians (N = 23), and 50% for pediatricians at the city hospital (N = 31). Despite high prevalence of hemoglobinopathies in the population served and screening results in EMRs, only 46.2% of providers surveyed at the academic center reported routinely checking results of their infant patients: 38.6% of pediatricians and 66.7% of family practitioners. Some respondents were unaware that results are available in the EMR. The proportion of providers checking screening results was not significantly affected by educational intervention (N = 40). Provision of recommended follow-up for a positive trait result was modestly improved, especially in referring families for genetic counseling (25% to 50%, p < .01). In contrast, most pediatricians (83%) at the city hospital routinely check and perform follow-up. ConclusionDespite access to results in the EMR and targeted educational outreach, follow-up of hemoglobinopathy screening by primary care varies widely across clinical sites.

A case study of haemoglobinopathy screening in the Netherlands: witnessing the past, lessons for the future

Objectives. In 2007 neonatal screening (NNS) was expanded to include screening for sickle cell disease (SCD) and beta-thalassaemia. Up until that year no formal recommendations for haemoglobinopathy (carrier) screening existed in the Netherlands. Although it has been subject to debate in the past, preconceptional and prenatal haemoglobinopathy carrier screening are not part of routine healthcare in the Netherlands. This study aimed to explore the decision-making process of the past: why was the introduction of a screening programme for haemoglobinopathy considered to be untimely, and did ethnicity play a role given the history in other countries surrounding the introduction of haemoglobinopathy screening? Design. A witness seminar was organised, inviting key figures to discuss the decision-making process concerning haemoglobinopathy screening in the Netherlands, thereby adding new perspectives on past events. The transcript was content-analysed. Results. The subject of haemoglobinopathy screening first appeared in the 1970s. As opposed to a long history of neglect of African-American health in the United States, the heritage of the Second World War influenced the decision-making process in the Netherlands. As a consequence, registration of ethnicity surfaced as an impeding factor. However, overall, official Dutch screening policy was restrained regarding reproductive issues caused by fear of eugenics. In the 1990s haemoglobinopathy screening was found to be ‘not opportune’ due to low prevalence, lack of knowledge and fear of stigmatisation. Currently the registration of ethnicity remains on the political agenda, but still proves to be a sensitive subject. Discussion. Carrier screening in general never appeared high on the policy agenda. Registration of ethnicity remains sensitive caused by the current political climate. Complexities related to carrier screening are a challenge in Dutch healthcare. Whether carrier screening will be considered a valuable complementary strategy in the Netherlands, depends partly on participation of representatives of high-risk groups in policy making.

Ethical implications and practical considerations of ethnically targeted screening for genetic disorders: the case of hemoglobinopathy screening

The prevalence of hemoglobinopathies differs among populations due to genetic differences and due to the protective effects of the heterozygote (carrier) state against malaria. Because of the difference in genetic distribution, public health programs have weighed the ethical versus practical implications of ethnically targeted versus universal newborn, and where applicable, prenatal screening. We examine newborn and prenatal screening for hemoglobinopathies in relation to the use of ‘race’ and ethnicity to assess risk for genetic conditions. First, categories of race/ethnicity are social constructs, therefore, observed or self-identified broad racial/ethnic categories are correlated but not necessarily reliable indicators of geographic ancestry or genetic risk. Second, targeting based on ethnicity poses serious issues of logistics and equity for public health programs and clinical services. In the past, newborn screening for hemoglobinopathies in the United States and United Kingdom was often selective, targeted to women of certain ethnic groups or areas with large concentrations of ethnic minority groups. Presently, newborn screening for hemoglobinopathies is universal in both countries and programs emphasize that individuals of all ethnic backgrounds are at risk for carrying a hemoglobin genetic variant. Reported race/ethnicity is still used as a criterion for offering prenatal carrier testing in the United States, where it is not a public health responsibility. In the United Kingdom, prenatal screening under the National Health Service is universal in high-prevalence areas and in low-prevalence areas is targeted based on reported ancestry. The continued use of targeted prenatal screening in both countries reflects the different purposes and modes of laboratory testing in newborn and prenatal screening. The ethical imperative to identify as many affected infants with life-threatening conditions as possible in newborn screening programs is not applicable to prenatal carrier testing. Because newborn screening dried blood spot specimens are tested for multiple disorders, targeted screening poses serious logistical challenges which is not the case in prenatal screening.

‘He's the dad isn't he?’ Gender, race and the politics of prenatal screening

Background. Men's involvement in prenatal screening is becoming increasingly important. However, despite the potentially significant role of fathers in haemoglobinopathy screening, their participation is under researched. Furthermore, the portrayal of Black and minority ethnic (BME) fathers tends to be based on persisting stereotypes of men as either absentee parents with limited roles in screening or as controlling decision-makers. Objective. To describe the influence of ethnicity and gender on the process of participation of men in antenatal screening for sickle cell and thalassaemia. Design. A qualitative study, using in-depth interviews and focus groups with 22 pregnant women from a range of socio-economic and ethnic backgrounds, 16 male partners and 15 midwives in a northern city in the UK. Results. Men from BME groups take a pragmatic and equitable role in screening with their partners. White British men on the other hand, while willing to participate in screening, take a more casual view of their own direct participation. Accounts from hospital midwives supported these findings. Conclusions. While acknowledging the importance of material connections between certain BME groups and blood disorders, two key issues are raised. First, BME men's involvement contribute a challenge towards existing assumptions often made about BME fathers. Second, White British men's participation can be useful in determining the genetic status of the foetus and therefore their role should not be neglected. Screening research and practice need to broaden out their focus on issues of gender, ethnicity and screening.

Genetic counseling following the detection of hemoglobinopathy trait on the newborn screen is well received, improves knowledge, and relieves anxiety

PurposeThe primary purpose of newborn screening for hemoglobinopathies is the presymptomatic diagnosis and early treatment of sickle cell disease. Hemoglobinopathy traits detected on the newborn screening provide an opportunity for genetic counseling of families regarding the trait and information that may impact reproductive decisions of the parents. We describe the results of a study to determine the impact of newborn screening and genetic counseling on the lives of families in which an abnormal hemoglobin trait had been identified. MethodsFrom June 2003 to December 2009, families of children with trait attending a clinic visit and receiving professional genetic counseling were asked to participate in a semistructured follow-up survey regarding their experience and the impact of genetic counseling on their families. ResultsOf the 300 patients seen in clinic during the specified time period, 209 consented to be recontacted and 114 have completed the survey. Eighty-five percent of responders reported knowing that the newborn screen had been performed, but only 55% understood the purpose of newborn screening. When asked about the effect of finding out that trait was present in their baby, 19% reported feeling guilty or upset, whereas 4% believed that their partner blamed them for the child's results. That genetic counseling was found to be beneficial was indicated by the fact that 99% reported that their questions were answered, 82% reported feeling less anxious, and 78% discussed the trait with their partner after the appointment. ConclusionGenetic counseling after newborn screening relieves anxiety, provides knowledge, facilitates dialog within families and between partners about hemoglobinopathy trait, and was seen as a positive experience for the majority of responders.

Internet‐based approach to population screening for common hemoglobinopathies in United Arab Emirates

This article reports on efforts to overcome common hurdles that were faced during population-based screening for common hemoglobinopathies in the United Arab Emirates. An Internet-based approach was designed and implemented to increase the acceptance of the screening program. The process involved: an awareness campaign, a simple bilingual (Arabic/English) online consent form and registration process, the use of a barcode for sample labeling, an equipment upgrade, electronic communication of a successful registration process, test results, and a counseling process. Before the implementation of the Internet-based system, great concern was noted among the clients in terms of the availability of accurate and timely test results, the need for pretest and post-test counseling, and the way that their personal health information was handled. Lapses in information exchange between the clients who participated in the screening program for the carrier state of inherited disorders and the screening laboratory posed significant challenges. The emphasis on confidentiality and the ease of access to services was instrumental in increasing the level of acceptance of these services in our community. Based on an analysis of > 10,000 samples, we conclude that Internet-based reporting holds much promise for improving the quality of care that clients receive.

Morning pre-prandial iron concentrations are higher in Beta-Thalassemia heterozygotes and correlates strongly with HbA2 levels

The inherited hemoglobinopathies are a large group of disorders that include thalassemias and hemoglobin variants. Accurate determination of the carrier phenotype is essential for detecting couples at risk for producing offspring with hemoglobinopathy. Heterozygous β-thalassemia is usually silent at the clinical level. His phenotype is characterized by microcytosis and hypochromia with increased hemoglobin A2 (HbA2) value. Therefore, HbA2 determination plays a key role in screening programs for hemoglobinopathy. The aim of this review is to address and suggest an approach for reducing or abolishing hemoglobinopathy screening mistakes.Quantitative methods for HbA2 value determination, comment on the accuracy of the test and on the interpretation of data were discussed. The most probable diagnostic conclusion based on the HbA2 level, hemoglobin pattern, hematological parameters and iron markers was suggested in this review.Hemoglobinopathies are the only genetic disease where it is possible to detect carriers using hematological findings rather than DNA analysis. However, hematological diagnosis is sometimes presumptive, and in these cases, DNA analysis becomes necessary. Complete screening is based on the detection of red cell indices, HbA2, HbF and hemoglobin variant values. In particular, HbA2 determination plays a key role in screening programs for β-thalassemia because a small increase in this fraction is one of the most important markers of β-thalassemia heterozygous carriers.Genetic factors both related and unrelated to the β- and α-globin gene clusters, iron metabolism, endocrinological disorders, and some types of anemia, together with intra- and inter-laboratory variations in HbA2 determination, may cause difficulties in evaluating this measurement in screening programs for hemoglobinopathies. Therefore, knowledge of all these issues is important for reducing or eliminating the risk of mistakes in screening programs for hemoglobinopathies.

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 β 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 78 fL and 27 pg, respectively. Using these cut off values in combination with the dichlorophenolindophenol test in screening of α 0 thalassemia, β 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.

Hemoglobin H newborn screening: let's not

y 2011 T he Journal has published data in support of adding various diseases to newborn screening protocols. In this issue, Kemper et al present a compelling case for not adding a particular disorder. The report is a model of the type of thoughtful consideration that should go into such decisions. Hemoglobin H (Hgb H) disease is a rare hemoglobinopathy associated with growth retardation, cholelithiasis, and a variety of other manifestations. Because of the shift to beta-globulin Hgb chains after the newborn period, Hgb H can only be detected easily within the newborn period. This has led to arguments in favor of adding it to sickle cell screening, and some states have adopted this process. This report presents a careful analysis of the published evidence against screening, as well as the experience in areas in which screening already occurs. The authors conclude that the evidence does not support newborn screening for the condition. Regardless of one’s interest in hemoglobinopathy screening, the nicely presented analysis in this report is an impressive example of the type of work that should inform policy decisions. This is timely because of the mounting political opposition to the development of evidence-based decision-making in medicine. Article page 780<

How I treat: the selection and acquisition of unrelated cord blood grafts

AbstractUse of unrelated donor cord blood (CB) as an alternative stem cell source is increasing, and yet there is little information to guide transplant centers in the unique aspects of the search and selection of CB grafts. There is no mechanism to easily access the global inventory of CB units, nor is the product information provided by all banks standardized. To address these challenges, this manuscript reviews the logistics of the search, selection process, and acquisition of CB grafts as practiced by our center. Topics include who should be considered for a CB search, how to access the global CB inventory, and how to balance total nucleated cell dose and human leukocyte antigen match in unit selection. We discuss aspects of unit quality and other graft characteristics (processing methods, unit age, availability of attached segments, infectious disease, and hemoglobinopathy screening) to be considered. We incorporate these considerations into a unit selection algorithm, including how to select double-unit grafts. We also describe how we plan for unit shipment and the role of backup grafts. This review aims to provide a framework for CB unit selection and help transplantation centers perform efficient CB searches.

Screening for Hemoglobinopathies in Allogeneic Cord Blood Units Using Capillary Electrophoresis

Screening for Hemoglobinopathies in Allogeneic Cord Blood Units Using Capillary Electrophoresis

Comprehensive healthcare for individuals with sickle cell disease

Comprehensive healthcare for individuals with sickle cell disease

Diagnostic Challenge Presented by “Hb F only” Pattern In Newborn Screening for Hemoglobinopathies: Approach to Accurate Diagnosis

AbstractAbstract 5173Newborn screening for hemoglobinopathies has been proven to be an effective means of early diagnosis of clinically significant hemoglobinopathies such as sickle cell syndromes with early recruitment to clinical care and resultant reduction in morbidity and mortality. Neonatal screening for hemoglobinopathies is currently performed in 50 states utilizing screening methods such as hemoglobin electrophoresis or isoelectric focusing (IEF) complemented by High Performance Liquid Chromatography (HPLC) in a large number of states. These two methods yield accurate diagnosis of hemoglobinopathies especially of sickle cell disease in the vast majority of cases, although occasionally additional diagnostic approaches such as DNA based tests may be required for precise genetic diagnosis. One of the diagnostic challenges in newborn screening for hemoglobinopathies is posed by the observation of “Hb F only” pattern in electrophoresis/IEF and HPLC. This pattern can result from a spectrum of inherited globin gene abnormalities including homozygous β0 thalassemia, homozygous δβ-thalassemia, homozygous deletional HPFH (Hereditary Persistence of Fetal Hemoglobin), or a compound heterozygosity for any two of the above abnormalities. Since the clinical phenotype is dependent upon the underlying molecular defect, accurate diagnosis of the genotype in “Hb F only” cases is crucial in predicting the clinical course and planning therapy. The clinical spectrum of “Hb F only” (100% Hb F) cases in newborn screening ranges from severe transfusion dependent homozygous β0 thalassemia to completely asymptomatic homozygous deletional HPFH with intermediate phenotypes due to compound heterozygosity for any two of the above mentioned abnormalities. The prediction of the clinical phenotype based on the genotype is therefore important in ascertaining the significance of “Hb F only” cases. We present two cases of “F-only” phenotype detected during newborn screening, which were found to result from two distinct genotypes. Case 1 was an 8 mo old African-American male born in Sinai Hospital of Baltimore, MD at 39 weeks of gestation who was found to have 100% Hb F during newborn screening. He was referred to Pediatric Hematology at Sinai Hospital at two months of age, at which time a Hb electrophoresis confirmed the presence of 100% Hb F. His CBC showed a Hb of 13 g/dl, Hct 39%, RBC 4.68, MCV 84 fl, retic count 2.9%. At 8 months, he continued to be asymptomatic. She had a follow-up visit at 20 months of age and had Hbg 11.7, MCV 62; no repeat electrophoresis at that time. Work-up at MCG Sickle Cell Center Laboratory confirmed 100% Hb F with normal Hb and Hct. A gap PCR with primers specific for HPFH-1 and HPFH-2 deletions showed that the patient was a compound heterozygote for these two deletions. These findings were confirmed with family studies, which showed that the father was heterozygous for the HPFH-1 deletion, and the mother was heterozygous for HPFH-2. Case 2 was an African-American female born at UNC Hospital in Chapel Hill, NC. Newborn screening showed 100% Hb F. At age 2, she had a Hb of 11 g/dl, Hct 31.3%, MCV 80 fl. Hb analyses by HPLC revealed 96.2% Hb F, 2.9% Hb A, 0.9% Hb A2. Molecular analyses showed that the patient was a compound heterozygote for the HPFH-1 deletion and the β-globin promoter mutation, -90 C→T. These results were confirmed with family studies, which revealed that the father carried the HPFH-1 deletion while the mother was heterozygous for the rare -90 C→T mutation in the β-globin promoter. These two cases serve to illustrate the importance of detailed molecular diagnostic work up for the definite diagnosis of the genotype in “Hb F only” or 100% Hb F cases identified during neonatal screening for hemoglobinopathies. Since the phenotype of “100% Hb F” in a newborn can result from a variety of genotypes with a wide ranging spectrum of phenotypic expression, accurate genetic diagnosis is crucial in predicting the clinical course and determining the appropriate course of action. A stepwise approach to the work-up and the use of a combination of sensitive methods such as IEF, HPLC, and gene analysis will be helpful in establishing the correct diagnosis. Disclosures:No relevant conflicts of interest to declare.