Haemoglobin LeporeBoston in a Turkish family.
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Haemoglobin Lepore was demonstrated in four members of a Turkish family. It was found in the heterozygote state and was associated with erythrocyte morphology similar to that observed in the beta thalassaemia trait. The average concentration of haemoglobin Lepore was 8.1% of the total haemoglobin. Structural analysis showed that the Lepore haemoglobin was the LeporeBoston type. This is the first reported instance of the occurrence of haemoglobin Lepore in Turkey. (+info)
Costing model for neonatal screening and diagnosis of haemoglobinopathies.
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AIM: To compare the costs and cost effectiveness of universal and targeted screening for the haemoglobinopathies; to compare the cost of two laboratory methods; and to estimate the cost effectiveness of programmes at different levels of prevalence and mix of haemoglobinopathy traits. METHODS: A retrospective review of laboratory and follow up records to establish workload and costs, and estimation of costs in a range of circumstances was made in a haematology department and sickle cell and thalassaemia centre, providing antenatal and neonatal screening programmes in Inner London. The costs for 47,948 babies, screened during 1994, of whom 25 had clinically significant haemoglobinopathies and 704 had haemoglobinopathy traits, were retrospectively assessed. RESULTS: The average cost per baby tested (isoelectric focusing and high power liquid chromatography) was 3.51 Pounds /3.83 Pounds respectively; the cost per case of sickle cell disease identified (IEF/HPLC) was 6738 Pounds /7355 Pounds; the cost per trait identified (IEF/HPLC) was 234 Pounds /255 Pounds; the cost per extra case of SCD and trait identified by universal programme varied. CONCLUSIONS: IEF and HPLC are very similar in terms of average cost per test. At 16 traits/1000 and 0.5 SCD/1000 there was no significant identification cost difference between universal and targeted programmes. Below this prevalence, a targeted programme is cheaper but likely to miss cases of SCD. If targeted programmes were 90-99% effective, universal programmes would cease to be good value except at very high prevalence. Greater use of prenatal diagnosis, resulting in termination, and therefore fewer affected births, reduces the cost effectiveness of universal screening. Screening services should aim to cover a screened population which will generate a workload over 25,000 births a year, and preferably over 40,000. (+info)
Evaluation of cation-exchange HPLC compared with isoelectric focusing for neonatal hemoglobinopathy screening.
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BACKGROUND: Central Middlesex Hospital, in northwest London, has screened neonates for hemoglobinopathies, using the established manual technique of isoelectric focusing (IEF) since 1989. Recently, this laboratory has faced a large increase in the number of samples tested per year. This study compared the detection of hemoglobin abnormalities between the existing manual IEF method and that of automated cation-exchange HPLC to determine the reliability of HPLC and whether an automated system would save time in the laboratory. METHODS: Over a 15-month period, 25 750 blood samples, collected by heel prick onto filter paper, were tested using HPLC, and the results were compared with those obtained with IEF. RESULTS: HPLC and IEF each identified 568 patients with FAS, 151 with FAC, 49 with FAD-Punjab, 23 with FS, 3 with FC, 6 with FSC, 5 with FE, and 1 with FD. IEF detected 62 patients with FAE, whereas HPLC detected 63. This additional FAE was observed on repeat IEF. One additional heterozygote detected by HPLC was initially not observed by IEF, but was detected on repeat IEF. HPLC detected all but six cases of Hb Barts observed by IEF. One double heterozygote and four heterozygotes were detected by IEF, but not by HPLC. The detection of hemoglobin variants expressed at low concentrations was comparable for the two methods, and carryover was not observed in routine analysis on HPLC. CONCLUSIONS: HPLC is a sensitive, efficient, and time-saving alternative to IEF for the neonatal screening of common hemoglobinopathies. (+info)
Multicenter evaluation of Tosoh glycohemoglobin analyzer.
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BACKGROUND: We describe an Anglo-French evaluation of a new analyzer. METHODS: The Tosoh HLC-723 GHb V, A1c2.2 glycohemoglobin analyzer is an HPLC instrument with primary blood tube sampling, bar-code reading, cap piercing, and the ability to chromatographically separate labile hemoglobin A1c (HbA1c). We evaluated two analytical protocols, 2.2 and 3.0 min, and compared results for blood samples collected from diabetic and nondiabetic subjects with those obtained with Bio-Rad Diamat and Variant analyzers. RESULTS: Within- and between batch-imprecision (CVs) was <2% with linearity to at least 15.9% HbA1c. Although some hemoglobinopathies were detected in the 2. 2-min chromatography, clearer evidence of abnormality was visible in the 3.0-min version. Comparison with established methods showed good correlation (r = 0.993; n = 316 with Diamat; and r = 0.995; n = 133 with Variant) but highlighted calibration differences. CONCLUSIONS: The problems of manual blood sample preparation, labile HbA1c, and carbamylated hemoglobin interference associated with the older instruments have been eliminated in the new Tosoh analyzer. The 3. 0-min protocol is preferred for routine use. (+info)
An analysis of relative costs and potential benefits of different policies for antenatal screening for beta thalassaemia trait and variant haemoglobins.
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AIMS: To investigate the costs and potential benefits of different policies for antenatal screening for haemoglobinopathies in two multiethnic London communities. METHODS: 1000 consecutive antenatal patient samples referred to each of two London teaching hospital laboratories for haemoglobinopathy testing were investigated using the standard procedures of the laboratory in question. When the standard procedures did not include high performance liquid chromatography (HPLC), this technique was added, in order to assess its diagnostic value and cost-effectiveness. A comparison was made between the costs and potential benefits of universal testing for variant haemoglobins and beta thalassaemia trait using HPLC and the costs and potential benefits of universal testing for variant haemoglobins and selective testing for beta thalassaemia trait using the mean cell haemoglobin (MCH) as a screening test and less automated techniques than HPLC for definitive diagnosis. RESULTS: The costs of the two policies were found to be comparable, as the higher reagent/instrument costs of HPLC were offset by the lower labour costs. Universal testing of 2000 consecutive samples did not disclose any extra cases of beta thalassaemia trait which would not have been detected by universal screening and selective testing. However, six patients were found to have a haemoglobin A2 variant which can interfere with the diagnosis of beta thalassaemia trait. CONCLUSIONS: The introduction of universal testing by HPLC into British laboratories could be cost neutral and has potential benefits. If a higher cost is accepted then the greater degree of automation could be used to release skilled staff for other tasks within the laboratory. (+info)
From genotype to phenotype: genetics and medical practice in the new millennium.
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The completion of the human genome project will provide a vast amount of information about human genetic diversity. One of the major challenges for the medical sciences will be to relate genotype to phenotype. Over recent years considerable progress has been made in relating the molecular pathology of monogenic diseases to the associated clinical phenotypes. Studies of the inherited disorders of haemoglobin, notably the thalassaemias, have shown how even in these, the simplest of monogenic diseases, there is remarkable complexity with respect to their phenotypic expression. Although studies of other monogenic diseases are less far advanced, it is clear that the same level of complexity will exist. This information provides some indication of the difficulties that will be met when trying to define the genes that are involved in common multigenic disorders and, in particular, in trying to relate disease phenotypes to the complex interactions between many genes and multiple environmental factors. (+info)
Iron deficiency is a more important cause of anemia than hemoglobinopathies in Kuwaiti adolescent girls.
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Anemia is the most prevalent nutritional problem worldwide, due mainly to iron deficiency. Studies of anemia are less common in adolescents than in women and children. We examined anemia prevalence in adolescent Kuwaiti schoolgirls, and its association with hemoglobinopathies as well as the most common environmental cause, Fe deficiency. A cross-sectional sample of 1051 healthy adolescent schoolgirls was studied. Sample size was based on WHO criteria. Anemia, Fe deficiency and hemoglobin (Hb) variations were studied by Hb concentration, erythrocyte protoporphyrin (EP) and an HPLC quantitation, respectively. Of the subjects sampled, 30% were anemic. Mildly elevated EP values were found in 68%. Girls with high EP levels were more likely (P < 0.001) to be anemic than girls with normal EP. Up to 25% of the girls may have had Fe deficiency anemia. Hemoglobinopathies were neither prevalent nor significantly associated with anemia. These data indicate that environmental factors play a significant role in anemia among healthy, well-to-do Kuwaiti adolescent girls. (+info)
Evaluation of HbA1c determination methods in patients with hemoglobinopathies.
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OBJECTIVE: To evaluate commercially available determination methods for HbA1c in patients with hemoglobin variants. RESEARCH DESIGN AND METHODS: HbA1c values were determined with various commercially available methods, including ion-exchange high-performance liquid chromatography (HPLC), boronate affinity assay, and immunoagglutination in patients with the hemoglobin mutations Hb Graz, Hb Sherwood Forest, Hb O Padova, Hb D, and Hb S. RESULTS: The effect of hemoglobinopathies on glycohemoglobin measurements was highly method dependent. The HPLC methods for HbA1c determination lacked the resolution necessary to differentiate hemoglobin variants. They demonstrated additional peaks in the chromatograms and HbA1c results either too low or too high compared with the nondiabetic reference range. With all immunoassays, Hb Graz demonstrated falsely low values. The other hemoglobinopathies in our study caused falsely low and/or high HbA1c results in immunoagglutination methods. The boronate affinity method showed values in an acceptable range for all hemoglobin variants. CONCLUSIONS: Because of the local occurrence of Hb variants and the ethnic origin of a given population, every individual laboratory must establish and validate its own assay method. In managing diabetic patients, knowledge of hemoglobinopathies influencing HbA1c determination methods is essential because hemoglobin variants could cause mismanagement of diabetes resulting from false HbA1c determinations. (+info)