Hemoglobin Chapel Hill masquerading as hemoglobin S in newborn sickle cell screening: A case study.

Antenatal screening/testing of pregnant women should be carried out according to the guidelines of the NHS Sickle Cell and Thalassaemia Screening programme. Newborn screening and, when necessary, follow up testing and referral, should be carried out according to the guidelines of the NHS Sickle Cell and Thalassaemia Screening programme. All babies under 1 year of age arriving in the UK should be offered screening for sickle cell disease. Preoperative screening for sickle cell disease should be carried out in patients from ethnic groups in which there is a significant prevalence of the condition. Emergency screening with sickle solubility tests must always be followed by definitive analysis. Laboratories performing antenatal screening should utilize methods capable of detecting significant variants and be capable of quantitating haemoglobins A 2 and F at the cut-off points required by the national antenatal screening programme. The laboratory must ensure a provisional report is available within three working days from sample receipt.

Newborn screening (NBS) for hemoglobinopathies facilitates early identification of affected individuals to ensure the prompt institution of comprehensive medical care for affected newborns in California. When linked to extensive follow-up and education, NBS has been shown to significantly reduce mortality in children with sickle cell disease. Due to changing immigration patterns from Asia and Latin America, the State of California has witnessed an increased prevalence of clinically significant hemoglobin (Hb) disorders, including those resulting from novel genotypes. In 1999, newborn screening for Hb H disorders was incorporated in the statewide hemoglobinopathy screening program. Primary screening for hemoglobin variants was performed using high performance liquid chromatography. Confirmatory testing on hemoglobinopathy mutations was performed by electropheresis techniques and genotyping methods. Of 530,000 newborn samples screened annually in California, 2,118 samples were referred to the Hemoglobin Reference Laboratory (HRL) for confirmatory testing between January 1, 1998 and June 30, 2006 (0.05%). Sickle cell disease was most frequently observed (1 in 6,600 births) followed by alpha-thalassemia (1 in 9,000 births) and beta-thalassemia disease (1 in 55,000 births). The confirmatory analysis modified the initial screening in 5% of cases and revealed 25 rare or new genotypes. Diverse ethnicities were associated with hemoglobin mutations including Southeast Asian, Black, Indian/Asian, Middle Eastern, and Hispanic. The California hemoglobinopathy screening program provides accurate diagnosis of hemoglobinopathies. Increasing incidence of diverse mutations require new strategies of laboratory screening, counseling, and patient management.

Sickle cell disease (SCD) and other hemoglobinopathies are a major health concern with a high burden of disease worldwide. Since the implementation of newborn screening (NBS) for SCD and other hemoglobinopathies in several regions of the world, technical progress of laboratory methods was achieved. This short review aims to summarize the current practice of classical laboratory methods for the detection of SCD and other hemoglobinopathies. This includes the newborn screening technologies of high-performance liquid chromatography (HPLC), capillary electrophoresis (CE), and isoelectric focusing (IEF).

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

Sickle haemoglobinopathies are among the most common genetic disorders in the world, affecting over 300 000 newborns annually, with estimates for further increases to over 400 000 annual births within the next generation (Piel et al, 2013). Both the World Health Organization (WHO) and United Nations have appropriately identified sickle cell disease (SCD) as a current global health burden. Ten years ago, the WHO estimated that haemoglobinopathies (mostly SCD, but also thalassaemia) were found in 71% of 229 countries, accounting for a substantial amount of mortality in children under 5 years of age (Modell & Darlison, 2008). The optimal care for children with sickle haemoglobinopathies begins with newborn screening (NBS), which can accurately establish the diagnosis before the onset of symptoms and allow early intervention with prophylactic penicillin, pneumococcal immunisations, caregiver education and preventive medical screening. In high-resource settings, access to hydroxycarbamide (hydroxyurea), a safe and effective disease-modifying therapy, provides an additional vital healthcare link between sickle cell diagnosis and treatment that helps reduce morbidity and mortality. In the United States, universal NBS for SCD has been in place for many years and represents a highly successful progamme (Therrell et al, 2015). England adopted a similar approach and recently reported a highly favourable initial evaluation (Streetly et al, 2018). In contrast, sickle cell screening and treatment programmes remain virtually non-existent in sub-Saharan Africa, which is disproportionately affected because of the high prevalence of sickle cell trait that confers protection against severe malaria. Europe and the UK now find themselves at crossroads with regard to NBS for SCD. Previously, few European countries had enough patients to warrant neonatal testing, and any limited testing typically used a targeted strategy based on ethnic ancestry. But migration patterns from the Middle East and Africa have changed dramatically over the past decade. Between 2010–2017, it is estimated that nearly 1 million sub-Saharan African migrants have sought asylum in Europe (Connor, 2018), and that trend is projected to continue well into the future. Nigeria, Ghana and Kenya are major sources of migrants to Europe, which is important when considering the very high prevalence of sickle cell trait and disease in these African countries. Migrant populations are often under-diagnosed and under-represented, particularly in European countries with low incidence rates, where migrant flow is rapidly changing (Martinez et al, 2014). Haemoglobinopathies are now found in all European countries with increasing prevalence (Inusa & Colombatti, 2017), an enlightening fact that prompted a pan-European consensus conference. In this issue of the Journal, Lobitz et al (2018) explain that the goals of this April 2017 conference were to summarise current European NBS efforts and epidemiological data, as well as identify key questions regarding the implementation and sustainability of comprehensive NBS programmes. Building on previous evidence-based guidelines, the manuscript includes a number of consensus statements and clear recommendations that form a backbone for future work by individual countries and the region as a whole. Many of the statements are well-accepted and therefore not controversial, such as highlighting the increasing burden of SCD in Europe; listing the sickle genotypes that can be accurately determined through NBS; describing laboratory methodologies that should be used for screening; stating the need for confirmatory testing, standardized data collection systems, and coordinated follow-up; and describing benefits of early diagnosis to improve clinical care. Somewhat surprisingly, there is no mention of offering disease-modifying therapy with hydroxycarbamide to children identified through the screening programme. An additional recommendation to evaluate screening programmes for cost-effectiveness is prudent, and likely to improve the scope and quality of the process. Taken together, these excellent recommendations represent best practices and should be adopted promptly by current and future European screening programmes. A few of the statements, however, may require further consideration before widespread adoption and implementation. Whom to screen, and specifically whether to recommend targeted screening of babies from certain ethnic ancestries versus universal screening of all babies, is really a question of resource allocation rather than scientific merit. The authors correctly recommend universal screening, because targeted screening will miss many affected babies due to a number of factors; accordingly, the suggestion about targeted screening as a "interim policy" solution is hard to justify for well-resourced European countries. Perhaps more debatable are the statements and recommendations about the best practice for babies who are identified as haemoglobinopathy carriers. Since these newborns do not have SCD, their trait status represents collateral information gained from the screening process and is not a true goal of the NBS programme. In the United States, efforts to track down babies with the most common forms of haemoglobinopathy trait (HbAS or HbAC), which is mathematically about 40 times the number of babies with SCD, have encountered logistical challenges and provided only modest evidence of success. While seemingly sensible and empowering for the affected families regarding future reproductive choices, there are legal, ethical and genetic issues related to trait notification. Should both parents also be tested, thus potentially leading to familial strife or even occasionally uncovering false paternity? Will one goal of counselling be to limit future offspring and prevent additional SCD births? Could a baby with asymptomatic HbAS or HbAC be subject to future medical or genetic discrimination? Such questions are difficult to answer, yet must be asked when considering the risks and benefits, as well as resources required, for notifying all families whose newborns are haemoglobinopathy carriers. This pan-European conference represents an important and pivotal first step towards wider NBS for the sickle haemoglobinopathies. These European and UK investigators deserve approbation for taking this opportunity to create consensus guidelines and recommendations for NBS practices. There is an urgent need to develop and initiate universal screening programmes across Europe, particularly in light of the rapid globalization of migration flows, which lead to greater diversity among populations and higher prevalence of SCD. Though it may take several years to implement and evaluate, the lessons of early and universal NBS across Europe can be predicted: reduced morbidity and mortality for children with SCD, which ultimately leads to better comprehensive care, higher quality of life for patients and reduced healthcare costs. Universal screening for SCD in Europe is an idea whose time has finally come.

HemoTypeSC Demonstrates >99% Field Accuracy in a Sickle Cell Disease Screening Initiative in Children of Southeastern Uganda.

The International Society for Neonatal Screening (ISNS) recognises six different geographical regions [...]

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.

Is integrating sickle cell disease and HIV screening logical?

Predictors of Hydroxyurea Use in Children with Sickle Cell Disease

Management of black children who present to a pediatric emergency department (ED) commonly requires knowledge of their sickle cell status. To determine the practice of sickle cell screening, 32 pediatric EDs were surveyed. Twenty-eight (88%) completed the survey, and, of these, 22 (79%) included sickle cell screening (differential solubility test for hemoglobin S) in the management of a black febrile six-month-old infant. To determine the method of screening for sickle cell disease, 60 consecutive black children less than two years of age, who presented to a pediatric ED, were reviewed prospectively. In 51 patients (85%), their condition warranted knowledge of their sickle cell status. Of these, parents of only nine (18%) children knew their child's sickle cell status. Thirty-five (69%) patients had a presumptive newborn screening test for sickle cell disease, but only 15 presented between 8 AM and 5 PM on a weekday, the time during which the newborn screening laboratory could be telephoned for test results. For these same 15 patients, 13 had private physicians, but only three physicians had results of newborn sickle cell screening tests. The patients' hospital records were reviewed, and nine (18%) patients had prior sickle cell screening tests, but five of these tests were performed before the child was six months of age. To determine sickle cell status, 30 (59%) patients required a sickle cell screening test in the ED. ED screening detected three (6%) newly diagnosed sickle cell trait patients. In summary, sickle cell screening is recommended for young black children who present to an ED with fever or signs and symptoms supportive of sickle cell disease complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Newborn screening (NBS) for sickle cell disease (SCD) requires a robust, high-throughput method to detect hemoglobin S (HbS). Screening for SCD is performed by qualitative methods, such as isoelectric focusing (IEF), and both qualitative and quantitative methods such as high performance liquid chromatography (HPLC), capillary electrophoresis (CE), and tandem mass spectrometry (MS/MS). All these methods detect HbS, as well as low-level or absent HbA, and also other variants of hemoglobin. HPLC is considered as a reference method for NBS, because of its high sensitivity and specificity in detecting HbS. NeoSickle®, a fully automated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platform, combined with automated sample processing, a laboratory information management system and NeoSickle® software for automatic data interpretation, has increased the throughput of SCD testing. The purpose of this study was to compare the performances of NeoSickle® and HPLC. A prospective study was conducted including 9,571 samples from the NBS program to compare MALDI-MS using NeoSickle® with an HPLC method. Correlation between the two methods was studied. For the MALDI-MS method, sensitivity, specificity, NPV, and PPV were calculated. We found over 99.4 % correlation between the HPLC and MALDI-MS results. NeoSickle® showed 100 % of sensitivity and specificity in detecting SCD syndrome, leading to positive and negative predictive values of 100 %. NeoSickle® is adapted to NBS for SCD, and can be used in first-line high-throughput screening to detect HbS, and beta-thalassemia major warning. When HbS is detected, second-line use of another specific method as HPLC is necessary.

Cost and Reliability of Two Methods of Hemoglobin Identification for Sickle Cell Newborn Screening in the Republic of Angola

Newborn screening for sickle cell disease, other hemoglobinopathies and G6PD deficiency is one of the most important means of decreasing mortality and morbidity in high prevalence areas. Nine years experience in newborn screening in Qatif Central Hospital are summarized. All newborns in Qatif Central Hospital had cord blood screening for sickle cell disease, other hemoglobinopathies and G6PD deficiency using alkaline and electrophoresis, agar gel electrophoresis for sickle cell disease and fluorescent screening technique for G6PD deficiency. Families of infants with minor hemoglobinopathies and G6PD deficiency were informed about the results in the well baby clinic. From December 1992 to December 2001, 24 012 newborn were screened. 21 858 (91.03%) were Saudi and 2154 (8.97%) were non-Saudi. In the Saudi hemoglobin electrophoresis patterns, AF (normal) was found in 49.52%, hemoglobin FS (sickle cell disease) + FS Bart s (sickle cell disease with alpha thalassemia) in 2.57%, hemoglobin AFS (sickle cell trait) + AFS Bart s (sickle cell trait with alpha thalassemia) in 21.14%, and alpha thalassemia (based on elevated Bart s hemoglobin > or = 2%) in 35.68%. G6PD deficiency was found in 37.02% and 21.27% in males and females, respectively. Of 563 Saudi newborn with a presumptive diagnosis of sickle cell disease, 48 (8.5%) did not come to the hematology clinic or were not contactable. The diagnosis of sickle cell anemia or sickle thalassemia was confirmed in 513 patients, and 2 cases were found to have sickle cell trait on repeat testing. Many parents found it hard to accept the initial diagnosis and the resulting impact on their relationship with one another. Prevention and early identification of sickle cell disease, other major hemoglobinopathies and G6PD deficiency remains the cornerstone of management of these diseases. The main barriers to successful neonatal screening for hemoglobinopathies are the level of the education and deficiency in manpower. We recommend including newborn screening for hemoglobinopathies and G6PD deficiency in the national hypothyroidism screening program in the eastern province and the establishment of a special center for hemoglobinopathies with a high standard of medical care in Qatif.

Cord blood screening of newborns for sickle cell disease was initiated in Florida at the Miami Sickle Cell Clinical Center in 1979 as a part of its participation in the national Cooperative Study of Sickle Cell Disease. Funding for newborn sickle cell screening in Florida began as a pilot project with a line-item appropriation in fiscal years 1983/84, and this funding for the three medical schools (University of Florida, University of Miami, and University of South Florida) continues to the present. During fiscal year 1984/85, a contract was negotiated between the University Hospital at Jacksonville and the local Children's Medical Services' office for the provision of newborn sickle cell screening. This contract has been renewed each year to the present. The primary objective in each of these programs is to identify babies with clinically significant hemoglobinopathies and to offer the services of the institution's pediatric hematology division. Additionally, education, genetic counseling, family studies, and appropriate referrals are provided for all babies found to have any hemoglobinopathy and for their family members. Initially, at the University of Miami, cord blood specimens were obtained at the time of delivery from at-risk (mostly black) mothers from whom informed consent had been obtained during a visit to one of several prenatal clinics associated with the University of Miami/Jackson Memorial (UM/ JM) Medical Center. It was soon discovered that many at-risk expectant mothers did not attend a prenatal clinic before their babies were born. Our internal review board did not consider consent "at delivery" informed consent.