Significant haemoglobinopathies: guidelines for screening and diagnosis

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. Disorders of globin chain synthesis, both thalassaemias and haemoglobin variants, are common in the UK and constitute a significant public health problem. Diagnosis may be required: (i) to confirm a provisional diagnosis, such as sickle cell disease or β thalassaemia major; (ii) to explain a haematological abnormality, such as anaemia or microcytosis; (iii) to identify an abnormality in the presymptomatic phase, as in neonatal screening; (iv) to identify fetuses at risk of significant haemoglobinopathies and offer the parents informed choice; (v) to permit genetic counselling of prospective parents; (vi) to identify the presence of sickle cell haemoglobin preoperatively. Improved fully automated systems and reagents for techniques such as high-performance liquid chromatography (HPLC) and isoelectric focusing (IEF) have led to their introduction in many laboratories. There is also increasing use of other methods to identify globin gene abnormalities including DNA analysis, mass spectrometry and immunological methods. There is therefore a need for an updated guideline defining the role of new techniques and their place in screening and in specific diagnostic settings. The detection of unstable haemoglobins, methaemoglobins and high and low oxygen affinity haemoglobins is not discussed but laboratories should either have methods for detecting these variant haemoglobins or should refer such samples to a reference laboratory. It should be noted that the identification of haemoglobins is often presumptive, based on electrophoretic mobility or other characteristics in an individual of appropriate family origin. Presumptive identification should be based on a minimum of two techniques based on different principles. Definitive identification usually requires DNA analysis, mass spectrometry or protein sequencing. Family studies are also of considerable importance in elucidating the nature of disorders of haemoglobin synthesis. As testing for haemoglobinopathies has implications for genetic counselling, informed consent should be obtained from individuals prior to testing. Throughout these guidelines the term ‘sickle cell disease’ (SCD) encompasses both homozygous and the compound heterozygous states that lead to symptomatic disease as the result of the presence of haemoglobin S. Sickle cell anaemia refers specifically to those homozygous for βS. These guidelines are intended for UK Haematologists and the approach to screening is that which is considered practical and feasible for the British population. Different strategies may be required for populations with a different prevalence of haemoglobinopathies. These guidelines are an update of previous guidelines [British Committee for Standards in Haematology (BCSH) 1988, BCSH 1994a,b, 1998] and were written by clinical and laboratory experts representing areas of high and low prevalence of haemoglobin disorders. A patient representative was also included. Sections relating to antenatal and newborn screening are based on policies produced by the laboratory subcommittee of the National Health Service (NHS) Sickle Cell and Thalassaemia Screening programme and available in the programme’s Laboratory Handbook (NHS Sickle Cell and Thalassaemia Screening updated guideline and were for in from to and were also The produced a which was by by of the Haematology of the British Committee for Standards in The guideline was by a of UK the BCSH and the British for Haematology Committee and as to and of are as in of the for for the BCSH The of haemoglobin and is in of different haemoglobins from of haemoglobin of haemoglobin by for of haemoglobin in the A as F F of haemoglobin with A to in of F be in are for have or have F for the 2 of and by when and is of haemoglobin by of A the haemoglobin by of may be in is produced in from and usually by of for the of and may be in at The of haemoglobin chain abnormalities clinical from and β chain abnormalities may be to in the neonatal testing for haemoglobinopathies is in groups testing is be to antenatal screening and within the of the is of the is to be feasible in but other should be to the of a for a and should offer The individuals must be informed of the or not an abnormality is an abnormality is variant or testing should be according to the antenatal testing testing should always be in women for and in those a is to have or be a for a significant the or other should be and the women a is to be the should be for haemoglobinopathies. screening for haemoglobinopathies is not in the UK but for groups screening for β thalassaemia may be or antenatal National Screening Committee antenatal screening for haemoglobinopathies significant haemoglobinopathies that should be are in The according to the antenatal is in a high or low prevalence for and high prevalence areas prevalence of or laboratory screening and use of the Family is low prevalence areas prevalence of screening is based on the individual risk by the family of the and by of the (NHS Sickle Cell and Thalassaemia Screening screening is the laboratory must ensure a provisional report is available within three working days from sample receipt. Screening in high prevalence The screening for high prevalence areas with a and or on a The women should also be to the or The to the laboratory should the of and the of the of the women should be and the including should be within the of (NHS Sickle Cell and Thalassaemia Screening National for and Health women for the in should be offered testing the be both to and Screening in low prevalence low prevalence areas is that women be offered screening and the to their family and that of the All should have an and the cell should be and on in a as for high prevalence is to those women or the family is not or is of a haemoglobin a significant variant is should be by a haemoglobin or the was and the should be offered screening for the definitive result has not or result is not haemoglobins of clinical in are haemoglobins and variant haemoglobin is is when is the cell haemoglobin is of in the presence of a for β A of with a should be as may a β thalassaemia that testing of the the is on a of should be considered a may variant haemoglobins also have a to that of on F the of an an F of for thalassaemia and testing of the is the presence of a of haemoglobin should be thalassaemia the of a variant and β or thalassaemia thalassaemia states should be considered the is should be considered of as there is in the antenatal to the is the individual should be for the of thalassaemia in the of or family origin. Family that that thalassaemia is are in for these laboratory is for thalassaemia or which may also be in these ethnic thalassaemia is in many ethnic with a high in of and both are there is risk to the thalassaemia is not a significant with to genetic or but diagnostic with thalassaemia or have a of and a of are have a as in for the is and thalassaemia is the approach that use of is to the family and cell of the and to DNA analysis, in the and the both are at risk of there is in a sample from the or is not is appropriate to the The of women with haemoglobin disease also for for DNA testing is a be obtained at the antenatal to to anaemia may be offered as an to DNA testing from to in the is thalassaemia in other ethnic populations and in individuals in and other of the there is also a significant prevalence of which to haemoglobin disease in from such areas should be but in DNA and testing is not The of should be on It should be noted that a of β thalassaemia not thalassaemia and, in ethnic groups with a significant prevalence of the DNA is when to has β thalassaemia and the other thalassaemia both should be offered testing for National Screening Committee and NHS is that newborn babies should be for screening should also be to babies under the age of 1 year in the UK (NHS Sickle Cell and Thalassaemia Screening The of the newborn screening programme is to in and The screening programme also other variant haemoglobins by of the methods the of F or of a low of haemoglobin A on the newborn identify the of babies with β thalassaemia screening is based on the place of and is at the age of days as of the newborn screening programme testing of samples that a significant abnormality is consent is required and parents have the to out of testing the programme is out should be significant that should be are in that are or have a be and need to be from significant sickle to be from of and to be from counselling and testing is for babies in there is the of a significant abnormality and are to the and health at the place of the the of testing and clinical should be in a that be by of is to babies from of age but is the has is also for babies with F have in or in the neonatal are DNA techniques for the presence of the sickle gene as the NHS Sickle Cell and Thalassaemia Screening programme. is not available or is testing should be from the of variant haemoglobins of clinical or genetic haemoglobins also be and in the and health at the place of the should be and parents offered testing may be by a or other with the informed consent of the or by a an abnormality that requires is in individuals to have cell or of a testing for sickle cell is in testing by the laboratory on It is to prior to presence clinical should be by clinical on the of a clinical and of family origin. All patients from groups with a high prevalence of should be offered testing as of disease may be and the presence of may also cell techniques a risk of cell and are and the use of should be considered there is on which to counselling should be testing that patients are to their informed consent as there may be implications for patients are of the sickle cell The or should be informed of the of when and the result in the to testing. should be offered the result of the is for and haemoglobin or a diagnostic should be at the an an and a sickle solubility should be in should be and must be followed by definitive testing for should be from often are for haemoglobinopathies. patients a clinical and and the should be with other laboratory in the of the clinical and family origin. there is appropriate tests for and anaemia of disease should be and testing for thalassaemia considered in patients of appropriate family origin. on such tests may be by the laboratory. laboratories use to when to such but should be noted that such are not to be in or pregnant women or in patients may have the and cell should therefore be considered in the cell are not of thalassaemia or may be in the new in the UK with a of or significant thalassaemia patients with including with the of the of patients with or β thalassaemia or other to the F or is but should be noted that on F the of other haematological disorders or laboratory should screening/testing of their patients of should and screening/testing of patients of age when testing is to the out should always out screening and, when necessary, testing of both the the 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. under 1 year of age arriving in the UK should be offered screening for as of the screening programme. Preoperative testing should be carried out in patients from ethnic groups in which there is a significant prevalence of sickle cell Emergency screening with a sickle solubility and must always be followed by definitive analysis. The need to for thalassaemia and haemoglobinopathies should be considered in patients with with are by or with should be The of fully automated systems and reagents for such as and have led to their introduction in a of as a screening The use of mass spectrometry is for variant identification and may have for screening The of and be based on of sample or of and and the for are the are a to may be when many samples are to be and of the techniques for haemoglobin are the of guideline but are available in at a is and It the provisional identification of haemoglobins and a of common variant haemoglobins to a be obtained by on or The provisional identification of variant haemoglobin should be by at of an the that a in either the or a compound heterozygous such as or and or a patient has the that a compound for a variant haemoglobin and thalassaemia must also be haemoglobins, such as be by of haemoglobin by is not as the is not for the of β thalassaemia is when a of samples are to be liquid chromatography be for the of haemoglobins and F and for the provisional identification and of many variant usually of and is therefore for the of β thalassaemia systems are as the diagnostic in laboratories with a high with haemoglobin has the 1 The are therefore and permit of 2 sample are for analysis. of and variant haemoglobins is available on identification of a of variant haemoglobins be chain variants of which is in the of β thalassaemia are liquid chromatography usually haemoglobins and from both and often with other haemoglobins with and but may be by has the that also and other of which of haemoglobin with haemoglobin of is As with of haemoglobin analysis, should be with of variants is and methods should be for is as the screening is to and the of the which are as the identification of variants is by the or the that the at a is as as the of the and F and should be should be focusing is for the of or of F from A and significant variant haemoglobins and be the for screening of has not for has and the that variants also has the that haemoglobin F and A and and for other of variants is and methods should be for analysis. The for sickle cell solubility tests that are in the UK haemoglobin to a of in as low as The of to a of The methods are therefore capable of detecting of sickle cell the of when there is thalassaemia not when there is have in patients with high protein and in patients when the of is in the The be by a sample of or the All and sickle solubility tests should be by or an both for of the presence of and to sickle cell from sickle cell anaemia and from compound heterozygous an be with with a sickle solubility with a and a It is also that sickle solubility tests be by or an sickle solubility testing should be an haemoglobin is that in the of the by or is in the of on or a sickle solubility is not in an the age of a result may be a sickle solubility be in an prior to as is is that clinical the be The of the report on such a must that a not the presence of a low of haemoglobin and that testing is and are of in with are in there is an of β globin which always from a of be in of thalassaemia and in disease as as in thalassaemia and and disease. of has to and homozygous and heterozygous These two are the lead to a with in the homozygous are to in is an which is and has by DNA analysis. of is to confirm the of in which are in of It is also to for in of or disease. of these are when there is in the presence of clinical the is of in these be The of from in of to in disease. chromatography or may be to with is but in a laboratory performing the and are not is the is and the cell are of β thalassaemia and may in the and should be considered the is other haemoglobin variants in the should be of F is F is in thalassaemia or thalassaemia and such as and A may in of these DNA testing has use in the UK a be to confirm that in the F on is The is for the of F but by has the of and the of which lead to a significant at high there be from and variant haemoglobins that with F by Screening for The must be capable of detecting the common significant haemoglobin variants, and and must be for screening for The techniques be in antenatal screening for haemoglobin liquid chromatography (HPLC) focusing (IEF) should be by a different that is appropriate for the that be for those is or is not as a screening Sickle solubility testing be as of an that the presence of sickle haemoglobin Screening for are cell in with of of of and cell is that is to for thalassaemia as is These are usually for is by or an an for use in antenatal screening for sickle cell and need to be in A national cut-off of or has as the in the of of β A of for F has for the of a haemoglobin in The must therefore be to and F with and at these and the haemoglobin variants as by the antenatal screening programme. should be for Laboratories should place and be that on or on of are to be (NHS Sickle Cell and Thalassaemia Screening liquid chromatography systems must be to variant to or chain variants, and These should be the a patient with an the cut-off be required the is or an programme for and laboratories should ensure that the of and F is not may a different the with the and of or in or electrophoretic other need to be considered when many is in the presence of S. is not a in sickle cell the of A is and the is in The may be by up to in of with may β thalassaemia with or or the of or antenatal the in the and DNA when The thalassaemia risk to be considered in the of the family of the The risk is for β but the risk of should not be with cell and a F usually be as β thalassaemia in of are with an of anaemia the up to of anaemia should be and the haemoglobin when the patient is pregnant women there is for the for haemoglobinopathies as the of be offered It may be appropriate to pregnant women for or but is not specifically of The NHS Sickle Cell and Thalassaemia Screening that be offered screening for variant haemoglobins and guidelines have 1988, The for sickle screening is the as for the other newborn screening and samples are at such as in the of a testing in of screening be carried out on the a liquid sample from the must be in a laboratory in the of newborn methods of are for newborn screening for sickle cell disorders from and of these is for the for testing to the of the methods DNA analysis, immunological reagents or may be for newborn screening but have not fully The of and for newborn screening has the that the also the F and haemoglobins, which the of the haemoglobin to the the of the presence of should also be The must be capable of detecting the common significant haemoglobin variants, and in to F and samples are of F with A and of F and The must therefore be and in of detecting of A and the haemoglobin in the presence of of It is also to that the identification of a haemoglobin variant screening methods is variants the screening The and are for the methods identification of haemoglobin variants be by either protein mass or DNA analysis. laboratory screening should be by a different that is appropriate for the Laboratories performing antenatal screening should utilize methods capable of detecting significant variants and be capable of A 2 and F at the cut-off points required by the national antenatal screening programme. of A 2 by is not A sickle cell solubility is not in the age of and is not as a screening in an All sickle solubility tests should be by or an of may be in the of laboratory tests but should not testing in the antenatal screening programme. for thalassaemia and should not be for Laboratories should be of the that may not be when the Antenatal and Newborn Screening and also of the of on the of a of laboratory laboratories to with their and on in is required for laboratory and is an of clinical National Health Service requires antenatal and newborn screening laboratories both to in an and to the in the UK National for of are to written for their to be to the of the National for Sickle and Thalassaemia Screening in the of Laboratory for antenatal and newborn screening have by the NHS Sickle Cell and Thalassaemia Screening programme and are available in their laboratory (NHS Sickle Cell and Thalassaemia Screening The by the National Screening which is to should DNA is in a of and not usually in those thalassaemia is The of at risk of a with β thalassaemia or should be by laboratory techniques the antenatal screening programme. The of thalassaemia is DNA is the to and is not practical to to confirm of thalassaemia by DNA the is common and not usually is not for DNA laboratories to on such of thalassaemia are common was and methods for their detection are not (NHS Sickle Cell and Thalassaemia Screening the genetic risk that antenatal screening according to the antenatal screening and which of samples for studies by DNA other should be by a in the for haemoglobinopathies is a of the of haemoglobin disorders that are The National Screening has produced a of report for both newborn and antenatal screening that should and of to be in a (NHS Sickle Cell and Thalassaemia Screening of the of haemoglobin variants and thalassaemia there always be that tests on different or family studies a be on screening The sample must be be a has a a has within and may in should be when are should be from The should be and should be followed by a which may there is to be a in a an result should be which may be for the to with that clinical should also be to the on newborn there is that the presence of F is in from the is in to a the of the in those of the as haemoglobin cell must be in the on is should be in the of the sickle solubility in the of from an should be as an The report with from the and other appropriate tests should follow as as As the should always be both in and in in Sickle Cell or Sickle Cell The is for the to be in the of to is required may be to or to that testing is not antenatal identify abnormalities but the of the and techniques for haemoglobins at the of screening is The of haemoglobin variants is not and be by the identification usually be by DNA or mass be of to be but for the of the screening testing is required in with in an individual or in a and may be to other family definitive identification should be is a and testing a sample has not or the was for the of DNA testing for the sickle gene is for to the need for a at a is the Laboratory testing should utilize from their laboratory a may have not by the newborn screening programme. The be the haemoglobin has β thalassaemia as in the are the of of as have of F with considerable in the not by the newborn screening programme. The be the haemoglobin and, in cell are available thalassaemia as in the diagnostic testing is thalassaemia as be compound heterozygous or homozygous states of or clinical A is usually at and is at babies may not have A and therefore need testing to ensure A and that not have β thalassaemia and other β chain variants are at A may not be in a may also to the in a sickle cell from a with thalassaemia when the is the A Family studies and DNA testing may be to a not by the antenatal screening programme. The not be when the for both low and high prevalence β thalassaemia thalassaemia in risk groups haemoglobinopathies in of women with unstable or affinity haemoglobins The are when the for low prevalence haemoglobin variants in thalassaemia by disease or other of a in the β thalassaemia and thalassaemia in low risk a is The programme is not to at risk of a with disease. with may be by the newborn screening programme and may The may not be by laboratory affinity haemoglobins haemoglobins of family origin. The antenatal programme is on the of from the family in the high prevalence areas may result in and with to thalassaemia low prevalence that women screening family is DNA testing is required to ensure that tests for the appropriate are included. The of is on and to ensure that women the importance of and not of and not of and their but also of when the family is or not by a patients are as which a significant in low prevalence laboratories. The in the was to antenatal and newborn screening programme for haemoglobinopathies and (NHS The national requires that should not the that must be by newborn and antenatal A for the is to the of screening and and be by the two screening All are required to have a national on the of antenatal and newborn screening Different different systems for which should of risk is required screening laboratories as to which should be to the newborn screening laboratory and by in high prevalence areas may be practical to ensure that to be at risk of a are in low prevalence areas may also be to also that are not at It is that a is for to the antenatal and in low prevalence areas may not be available to ensure that are A written for is including of risk may to and and detection and of National are available for and individuals It is considered to to those individuals with a and also to a definitive be The of to individuals with of a significant should be risk by The national screening have specifically to significant of these on such screening not to the of DNA patients should not be with that are of thalassaemia or of may to or for of should be to individuals with a should be to a definitive be should not be to individuals with thalassaemia by DNA testing. the and in these guidelines is to be and at the of to the the British of Haematology the for the of these National for Health Sickle or or 1 or 2 or or or or or or or or or tests or mass genetic neonatal or or mass risk or clinical isoelectric or high liquid or to or or or or or or or or or or or or or or or or or or or or or or or or or or or or or or or or or or and and