[Hemoglobin C Variant Affecting Glycated Hemoglobin Test Results: A Rare Case Report].

Hemoglobin (Hb) variants are common factors that affect the results of glycosylated hemoglobin (A1C) tests. Hemoglobin variants react differently to different testing methods. Herein, we presented the first ever report of the effect of hemoglobin C (Hb C) on the test results of A1C in the Chinese population. High performance liquid chromatography (HPLC) and capillary electrophoresis were performed to measure A1C. Hemoglobin electrophoresis was conducted to identify the hemoglobin variants. Hb sequencing was performed to determine the mutation sites on the ß chain. HPLC showed decreased A1C results, which could be corrected by electrophoresis, but the electrophoresis graph still showed abnormal peaks. The hemoglobin electrophoresis results suggested that there were hemoglobin variants, which hemoglobin sequencing results revealed to be Hb C. Uncommon variations in a specific population tend to be overlooked. To avoid clinical decision-making being affected by the results of a single test, we recommend that an explanatory reporting model be routinely adopted for A1C tests so that all reports always contain explanatory notes for the testing methodology and analysis of the graphs.

Southeast Asian Ovalocytosis and Hemoglobinopathies in Newborns: Prevalence, Molecular, and Hematologic Analyses.

OBJECTIVES: Southeast Asian ovalocytosis (SAO) is an inherited red blood cell (RBC) membrane disorder, whereas hemoglobinopathies are inherited globin gene disorders. In an area where both diseases are prevalent, the interaction between them resulting in variable hematologic parameters can be encountered. However, little is known about the genetic interaction of SAO and thalassemia. We investigated the prevalence of SAO and hemoglobinopathy genotypes among newborns in southern Thailand. PATIENTS AND METHODS: This study was carried out on 297 newborns recruited consecutively at Naradhiwas Rajanagarindra Hospital in the south of Thailand. The SAO was identified on blood smear examination and polymerase chain reaction analysis. Thalassemia genotypes were defined. Hematologic parameters and hemoglobin (Hb) profiles were recorded and analyzed. RESULTS: Among 297 newborns, 15 (5.1%) carried SAO, whereas 70 (23.6%) had thalassemia with 15 different thalassemia genotypes. Abnormal Hb including Hb C, Hb Q-Thailand, and Hb D-Punjab were observed in 5 newborns. It was found in the nonthalassemic newborns that RBC count, Hb, and hematocrit of the nonthalassemic newborns with SAO were significantly lower than those without SAO. The same finding was also observed in the thalassemic newborns; RBC count, Hb, and hematocrit of the thalassemic newborns with SAO were significantly lower than those without SAO. However, the mean corpuscular volume, mean corpuscular Hb, and RBC distribution width of the SAO-newborns were significantly higher. CONCLUSIONS: Both SAO and hemoglobinopathy genotypes are common in southern Thailand. One should take this into consideration when evaluating neonatal anemia and other hematologic abnormalities. Identification of both genetic defects and long-term monitoring on the clinical outcome of this genetic interaction should be essential to understand the pathogenesis of these common genetic disorders in the region.

Nanofocused Scanning X-ray Fluorescence Microscopy Revealing an Effect of Heterozygous Hemoglobin S and C on Biochemical Activities in Plasmodium falciparum-Infected Erythrocytes.

While there is ample evidence suggesting that carriers of heterozygous hemoglobin S and C are protected from life-threatening malaria, little is known about the underlying biochemical mechanisms at the single cell level. Using nanofocused scanning X-ray fluorescence microscopy, we quantify the spatial distribution of individual elements in subcellular compartments, including Fe, S, P, Zn, and Cu, in Plasmodium falciparum-infected (P. falciparum-infected) erythrocytes carrying the wild type or variant hemoglobins. Our data indicate that heterozygous hemoglobin S and C significantly modulate biochemical reactions in parasitized erythrocytes, such as aberrant hemozoin mineralization and a delay in hemoglobin degradation. The label-free scanning X-ray fluorescence imaging has great potential to quantify the spatial distribution of elements in subcellular compartments of P. falciparum-infected erythrocytes and unravel the biochemical mechanisms underpinning disease and protective traits.

Point-of-care screening for sickle cell disease in low-resource settings: A multi-center evaluation of HemoTypeSC, a novel rapid test.

Sickle cell disease (SCD) is a common, life-threatening genetic disorder that is best managed when diagnosed early by newborn screening. However, SCD is most prevalent in low-resource regions of the world where newborn screening is rare and diagnosis at the point-of-care is challenging. In many such regions, the majority of affected children die, undiagnosed, before the age of 5 years. A rapid and affordable point-of-care test for SCD is needed. The diagnostic accuracy of HemoTypeSC, a point-of-care immunoassay, for SCD was evaluated in individuals who had SCD, hemoglobin C disease, the related carrier (trait) states, or a normal hemoglobin phenotype. Children and adults participated in low-, medium- and high-resource environments (Ghana [n = 383], Martinique [n = 46], and USA [n = 158]). Paired blood specimens were obtained for HemoTypeSC and a reference diagnostic assay. HemoTypeSC testing was performed at the site of blood collection, and the reference test was performed in a laboratory at each site. In 587 participants, across all study sites, HemoTypeSC had an overall sensitivity of 99.5% and specificity of 99.9% across all hemoglobin phenotypes. The test had 100% sensitivity and specificity for sickle cell anemia. Sensitivity and specificity for detection of normal and trait states were >99%. HemoTypeSC is an inexpensive (<$2 per test), accurate, and rapid point-of-care test that can be used in resource-limited regions with a high prevalence of SCD to provide timely diagnosis and support newborn screening programs.

New approach to accurate interpretation of sickle cell disease newborn screening by applying multiple of median cutoffs and ratios.

BACKGROUND: The main goal of newborn screening (NBS) for sickle cell disease (SCD) is to detect affected neonates so that specific preventive care can be implemented. High-performance liquid chromatography (HPLC) used for NBS has high sensitivity and specificity, but we lack guidelines for quantitative hemoglobin (Hb) fraction interpretation. The purpose of this study was to determine cutoff values to standardize quantitative interpretation in SCD NBS for different clinical situation such as, red blood cell transfusion or beta-thalassemia, which can be real screening pitfalls. METHODS: Retrospective study of 75,026 samples from the neonatal screening program analyzed in our laboratory. Precise HbA and HbS percentages at birth were recorded and median values established for each gestational age, allowing percentage results to be expressed in normal gestation-specific multiples of the median (MoM). Three threshold values of clinical interest were determined. RESULTS: High levels of HbA (>2.5 MoM) allowed identification of newborns who received transfusions. Low levels of HbS (≤0.7 MoM) allowed detection of the association between HbS and other mutations of the beta-globin gene (i.e., HbHope, ß0-thalassemia, etc.). An HbA/HbS ratio <0.5 to distinguish healthy carriers from SCD with S/ß+-thalassemia. The screening accuracy for each threshold was established. The screening accuracy of low-level HbA, which is determinant in identifying the subgroup of patients at risk of ß-thalassemia, will be determined prospectively. CONCLUSIONS: This new approach introduces tools for a quantitative interpretation in SCD NBS by HPLC methods and could allow standardization of interpretation between centers.

Hemoglobinosis C in Morocco : A report of 111 cas.

BACKGROUND: - Hemoglobin C is a hemoglobin variant encountered worldwide. The regionswith high prevalence are West Africa and South-East Asia.The objective of this study is to report cases of hemoglobin C disease brought together during these last twelve years in the Laboratory of Biochemistry and Toxicology of RabatMilitary Hospital Mohammed V (MHIMV). METHODS: - This was a retrospective study including111 cases of hemoglobin C disease collected in the Laboratory of Biochemistry of the MHIMVover the past 12 years. A questionnairewasfulfilledwith the epidemiological data,clinical data and the results of the biological explorations. The screening of the hemoglobin variant in this study included several biochemical (hemoglobin electrophoresis at acid and alkalinepH) and hematological tests. RESULTS: - Sex-ratio was equal to 1,22. The age at the time of diagnosis ranges between 4 and 80years old, with the mean of 38. North-West regions of Morocco seem most affected. The most frequent reasons for prescription of the hemoglobin's studywere: biological abnormalities, splenomegaly and anemic syndrome. Blood smear reveals frequently anisopoikilocytosis and red blood target. The biochemical tests contribute to the diagnosis and reveal various and varied etiological groups: heterozygous A/C (75%),homozygous C/C (8%), double heterozygous S/C (9%),C/ß+-thal (6%) andC/O-Arab (2%). Conclusion - The results of the present descriptive study are in line with the literature data. The importance of genetic counseling and the installation of a national card of systematic neonatal tracking seemto be unavoidable.

Erroneous HbA1c results in a patient with elevated HbC and HbF.

BACKGROUND: HbA1c is used in the diagnosis and monitoring of diabetes mellitus (DM). Interference from hemoglobin variants is a well-described phenomenon, particularly with HPLC-based methods. While immunoassays may generate more reliable HbA1c results in the presence of some variants, these methods are susceptible to negative interference from high concentrations of HbF. We report a case where an accurate HbA1c result could not be obtained by any available method due to the presence of a compound hemoglobinopathy. METHODS: HbA1c was measured by HPLC, immunoassay, and capillary electrophoresis. Hemoglobinopathy investigation consisted of a CBC, hemoglobin fractionation by HPLC and electrophoresis, and molecular analysis. RESULTS: HbA1c analysis by HPLC and capillary electrophoresis gave no result. Analysis by immunoassay yielded HbA1c results of 5.9% (Siemens DCA 2000+) and 5.1% (Roche Integra), which were inconsistent with other markers of glycemic control. Hemoglobinopathy investigation showed HbC with the hereditary persistence of fetal hemoglobin-2 Ghana deletion. CONCLUSION: Reliable HbA1c results may be unobtainable in the presence of some hemoglobinopathies. HPLC and capillary electrophoresis alerted the laboratory to the presence of an unusual hemoglobinopathy. Immunoassays generated falsely low results without warning, which could lead to missed diagnoses and under treatment of patients with DM.

Characteristics of a rapid, point-of-care lateral flow immunoassay for the diagnosis of sickle cell disease.

Sickle cell disease (SCD) is a common and life-threatening hematological disorder, affecting approximately 400,000 newborns annually worldwide. Most SCD births occur in low-resource countries, particularly in sub-Saharan Africa, where limited access to accurate diagnostics results in early mortality. We evaluated a prototype immunoassay as a novel, rapid, and low-cost point-of-care (POC) diagnostic device (Sickle SCAN) designed to identify HbA, HbS, and HbC. A total of 139 blood samples were scored by three masked observers and compared to results using capillary zone electrophoresis. The sensitivity (98.3-100%) and specificity (92.5-100%) to detect the presence of HbA, HbS, and HbS were excellent. The test demonstrated 98.4% sensitivity and 98.6% specificity for the diagnosis of HbSS disease and 100% sensitivity and specificity for the diagnosis of HbSC disease. Most variant hemoglobins, including samples with high concentrations of HbF, did not interfere with the ability to detect HbS or HbC. Additionally, HbS and HbC were accurately detected at concentrations as low as 1-2%. Dried blood spot samples yielded clear positive bands, without loss of sensitivity or specificity, and devices stored at 37°C gave reliable results. These analyses indicate that the Sickle SCAN POC device is simple, rapid, and robust with high sensitivity and specificity for the detection of HbA, HbS, and HbC. The ability to obtain rapid and accurate results with both liquid blood and dried blood spots, including those with newborn high-HbF phenotypes, suggests that this POC device is suitable for large-scale screening and potentially for accurate diagnosis of SCD in limited resource settings.

Hemoglobin Variants Acquired Post-Exchange Transfusion in Pediatric Sickle Cell Disease (SCD) Patients.

BACKGROUND: Many SCD patients receive chronic transfusions for prevention or treatment of disease related complications. Complications of the chronic transfusion noted in these patients include allergic reactions, transfusion transmitted infections, iron overload, and alloantibody formation. Even though hemoglobin (Hb) variants are prevalent in the general population, reports of transfusion-acquired Hb variants are rare. We performed a retrospective analysis on all SCD patients who underwent red cell exchange (RBCEx) transfusions at our institution during 2011-2013 to identify the presence of Hb variants acquired as a result of RBCEx. RESULTS: We found 66 occurrences of acquired Hb variants in 30 SCD patients during the period examined. The most commonly acquired Hb variant was Hemoglobin C (HbC) (64/66 occurrences). More than half of the patients (19/30) acquired HbC on multiple occasions (2-6 times). One patient acquired HbJ and another patient acquired HbD/G in addition to HbC. The segments from donor units were available in some of these cases and hemoglobin electrophoresis (HBE) was performed to confirm the presence of the variant Hb in the donor segments corresponding to that seen on the post-RBCEx sample. CONCLUSIONS: Heterozygous donors are asymptomatic and show no abnormalities during donor screening. Since HBE is not routinely performed on the donor specimen, it may go unrecognized until the post-transfusion recipient results pose diagnostic difficulties. There are no definitive guidelines on deferring these donors; hence one should be cognizant of these findings to prevent misdiagnosis. In a population where HbS negative blood is routinely requested, the effect of other Hb variants remains unknown. None of the patients in our study showed any adverse events due to the acquired Hb variants; however, this is of special concern in the pediatric population where a single RBC unit can contribute a significant portion of the exchanged blood volume. Additionally, donor centers may need mechanisms to confirm the findings and counsel the donors as needed.

Blood typing profile of a school-aged population of a North Togo township.

The aim of this study was the determination of hemoglobin (Hb) variants and ABO blood groups in a school population aged 6 to 9 years in the township of Agbandé-Yaka in North Togo. A cross-sectional study was carried out on 570 children of four primary schools at Agbande-Yaka, between March and July 2010. Hemoglobin characterization was done by alkaline buffer electrophoresis and the blood types ABO-Rhesus (Rh) D by immuno-hematological methods. A Hb variant was detected in 37.0% of the schoolchildren. Among them, the AS trait accounted for 11.9% and the AC trait for 20.2%. Homozygous Hb S (HBB: c.20A>T) was not found but Hb C (HBB: c.19G>A) appeared at a frequency of 3.3%, while compound heterozygotes carrying Hb SC were seen at a frequency of 1.6%. The O, B and A blood groups accounted for 49.0, 26.8 and 21.9%, respectively. The Hb anomalies reached a high prevalence in this school population. These results are remarkable by the absence of homozygous Hb S individuals compared to homozygous Hb C individuals, which were as numerous as expected. The frequencies of the ABO blood groups are similar to what has been found in other West African populations.

Study of a newly developed high-performance liquid chromatography analyser for glycosylated haemoglobin measurements in blood containing haemoglobin variants in the Japanese population.

BACKGROUND: This study examined the new high-performance liquid chromatography analyser HLC-723GX (GX) and investigated its ability to both measure glycosylated haemoglobin (HbA1c) values and determine whether haemoglobin variants could cause interference with these measurements in the Japanese population. METHODS: For the basic GX examination, the within- and between-run precision, linearity of measurements, correlation of HbA1c values with current systems and the interference of chemically modified haemoglobin were determined. GX interference caused by the haemoglobin variant was examined by analysing 39 clinical laboratory samples that contained haemoglobin variants. RESULTS: Good within- and between-run precision were found, with the coefficients of variation at ≤1.0%. A wide range of HbA1c measurement values were confirmed, with the HbA1c values strongly correlated with the results of the currently used HLC-723G8 system. Chemically modified haemoglobins were prepared by adding glucose, sodium cyanate, acetaldehyde or acetylsalicylic acid to normal blood samples. None of these samples had any influence on the HbA1c values determined by GX. GX analysis showed haemoglobin variants that eluted after HbA0 and were similar to HbD, or HbS had HbA1c values that were close to those measured by boronate affinity chromatography and immunoassay. GX found lower HbA1c values in blood that contained HbE or haemoglobin variants, which elute before or at nearly the same time as HbA0. CONCLUSIONS: GX is useful for the analysis of HbA1c samples that contain HbD, HbS, HbC and haemoglobin variants, even though the elution times are similar. However, a countermeasure is needed in order to avoid overlooking other haemoglobin variants in Japan.

Calidad de vida y satisfacción con el tratamiento de sujetos con diabetes tipo 2: resultados en España del estudio PANORAMA / Quality of life and satisfaction with treatment in subjects with type 2 diabetes: Results in Spain of the PANORAMA study

OBJETIVOS: La evaluación de la calidad de vida y la satisfacción con el tratamiento relacionados con la diabetes tipo 2 han sido poco estudiados. Ambos son los objetivos principales del estudio PANORAMA (NCT00916513). También se evalúa el grado de control metabólico, los patrones de tratamiento y la actuación del profesional sanitario. MATERIAL Y MÉTODOS: Estudio observacional, transversal y multicéntrico que incluyó pacientes diabéticos tipo 2 mayores de 40 años seleccionados de manera aleatorizada entre los centros de salud españoles. Se determinó la HbA1c mediante un mismo sistema y cada paciente completó cuestionarios de calidad de vida (EQ-5D y ADDQoL), satisfacción con el tratamiento (DTSQ) y temor a la hipoglucemia (HFS-II). RESULTADOS: Cincuenta y cuatro investigadores incluyeron 751 pacientes. El 60,3% presenta HbA1c < 7%. El mayor tiempo de evolución de la enfermedad y los tratamientos complejos, especialmente con insulina, se asocian a peor control. Cerca de un 25% de los pacientes en monoterapia presenta HbA1c ≥ 7%. Aunque la satisfacción con el tratamiento en general es buena (media 29,3 ± 6,1, escala de 0 a 36 puntos), los pacientes con peor control metabólico, hipoglucemias previas y tratamientos más complejos refieren significativamente peor calidad de vida y más miedo a sufrir hipoglucemias. CONCLUSIONES: Aunque el grado de control metabólico ha avanzado, todavía existen áreas de mejora. La adición precoz a la monoterapia de fármacos seguros ayudaría a lograr los objetivos de control sin aumentar el riesgo de hipoglucemias, y retrasando el inicio del tratamiento con insulina. Esto mejoraría la calidad de vida y la satisfacción con el tratamiento

OBJECTIVES: Few studies are available on quality of life and treatment satisfaction of patients with type 2 diabetes mellitus (T2DM). Both of them were the primary objectives of the PANORAMA (NCT00916513) study. Metabolic control, treatment patterns, and management by healthcare professionals were also evaluated. MATERIAL AND METHODS: This multicenter, cross-sectional, observational study randomly recruited > 40 year-old patients with T2DM from Spanish healthcare centers. HbA1c was measured using the same technique in all patients, who also completed quality of life (EQ-5D and ADDQoL) and treatment satisfaction (DTSQ) questionnaires and the Hypoglycemia Fear Survey (HFS-II). RESULTS: Fifty-four investigators recruited 751 patients, 60.3% of whom had HbA1c levels < 7%. Approximately 25% of patients on monotherapy had HbA1c values ≥ 7%, Patients with longer disease duration and more complex treatments, especially with insulin, showed the poorer control. Despite good overall treatment satisfaction (mean 29.3 ± 6.1, 0 to 36-point scale), patients with a poorer metabolic control, previous hypoglycemia episodes, and more complex therapies had a worse QoL and a greater fear of suffering hypoglycemia. CONCLUSIONS: Despite advances in metabolic control, there are still areas to improve. Early addition of safe drugs to monotherapy would help achieve control objectives without increasing the risk of hypoglycemia, and delaying the start of insulin therapy. This would also improve QoL and treatment satisfaction

HPLC-ESI-MS/MS analysis of hemoglobin peptides in tryptic digests of dried-blood spot extracts detects HbS, HbC, HbD, HbE, HbO-Arab, and HbG-Philadelphia mutations.

BACKGROUND: Hemoglobinopathies are mutations resulting in abnormal globin chain structure; some have clinically significant outcomes such as anemia or reduced lifespan. Five ß-globin mutations are (c.20A>T, p.E6V), (c.19G>A, p. E6K), (c.79G>A, p.E26K), (c.364G>C, p.E121Q), and (c.364G>A, p.E121K), resulting in HbS (sickle-cell hemoglobin), HbC, HbE, HbD-Los Angeles, and HbO-Arab, respectively. One α-globin mutation is (c.[207C>G or 207C>A], p.N68K), resulting in HbG-Philadelphia. METHODS: HPLC-ESI-MS/MS analysis of dried-blood spot (DBS) punches from newborns extracted with a trypsin-containing solution provides greater than 90% coverage of α-, ß-, and γ-globin amino acid sequences. Because the (c.20A>T, p.E6V), (c.19G>A, p. E6K), (c.79G>A, p.E26K), (c.364G>C, p.E121Q), (c.364G>A, p.E121K), and (c.[207C>G or 207C>A], p.N68K) mutations generate globin peptides with novel amino acid sequences, detecting one of these peptides in DBS extracts is indicative of the presence of a hemoglobinopathy in the newborn. RESULTS: The method described here can distinguish normal ß-globin peptides from the mutant HbS, HbC, HbE, HbD-Los Angeles and HbO-Arab peptides, as well as normal α-globin peptide from the mutant HbG-Philadelphia peptide, allowing the identification of unaffected heterozygotes such as HbAS, and of compound heterozygotes such as HbASG-Philadelphia. CONCLUSIONS: This HPLC-ESI-MS/MS analytical approach provides information that is not available from traditional hemoglobin analyses such as isoelectric focusing and HPLC-UV. It is also capable of determining the amino acid sequence of hemoglobin peptides, potentially allowing the detection of numerous hemoglobinopathies resulting from point mutations.

The distribution of haemoglobin C and its prevalence in newborns in Africa.

Haemoglobin C (HbC) is one of the commonest structural haemoglobin variants in human populations. Although HbC causes mild clinical complications, its diagnosis and genetic counselling are important to prevent inheritance with other haemoglobinopathies. Little is known about its contemporary distribution and the number of newborns affected. We assembled a global database of population surveys. We then used a Bayesian geostatistical model to create maps of HbC frequency across Africa and paired our predictions with high-resolution demographics to calculate heterozygous (AC) and homozygous (CC) newborn estimates and their associated uncertainty. Data were too sparse outside Africa for this methodology to be applied. The highest frequencies were found in West Africa but HbC was commonly found in other parts of the continent. The expected annual numbers of AC and CC newborns in Africa were 672,117 (interquartile range (IQR): 642,116-705,163) and 28,703 (IQR: 26,027-31,958), respectively. These numbers are about two times previous estimates.

Identification and quantification of hemoglobins in whole blood: the analytical and organizational aspects of Capillarys 2 Flex Piercing compared with agarose electrophoresis and HPLC methods.

BACKGROUND: The present study was conducted to evaluate the analytical performance and the organizational aspects of Capillarys 2 Flex Piercing system (CFP) respect to agarose electrophoresis and HPLC methods in hemoglobinopathies screening. METHODS: The measurement of imprecision in HbA 2 and HbF quantification was verified on HbA 2 CFP control and on three samples; 74 whole blood samples were used to evaluate migration time imprecision of hemoglobin variants S, C and E (HbS, HbC, and HbE); to compare methods, 451 samples were tested on CFP and HPLC; reference values were verified as value distribution in 160 blood donors and at ROC curve analysis on 449 samples from routine analysis. RESULTS: Imprecision: the analytical CV % s ranged from 1.25 to 3.9 at HbA 2 quantification, the CV % was 3.78 at HbF quantification; the running time imprecision for HbS and HbC and HbE ranged from 0.20 to 0.69 % . Method comparison: at regression analysis findings were HbA 2: CFP=1.21×HPLC­0.64, HbF: CFP=1.31×HPLC−0.75, HbS: CFP=1.10×HPLC−3.24. Reference values: the HbA 2 95th percentile range was 2.5­2.8; HbF was undetectable in 154 out 160 samples tested; at ROC curve analysis the best combination of sensitivity and diagnostic efficiency was obtained using 2.2 and 3.0, as reference values, for HbA 2 and 1.1 as the upper reference limit for HbF. Organizational aspects: with respect to the procedures currently implemented in our laboratory CFP requires 2 h less time and obviates the need for some manual steps. CONCLUSIONS: The quantification, reproducibility and diagnostic efficiency provided by CFP in identification and quantification of hemoglobins appear accurate. In addition, the use of primary tubes allows improved safety, and the avoidance of some manual steps, that prolong working time and are a source of possible errors.

Comparison of Sebia Capillarys Flex capillary electrophoresis with the BioRad Variant II high pressure liquid chromatography in the evaluation of hemoglobinopathies.

BACKGROUND: There are multiple biochemical screening techniques for assessing hemoglobinopathies. Here we compare a new instrument, the Sebia Capillarys Flex (capillary zone electrophoresis (CE)), with the BioRad Variant II (high pressure liquid chromatography (HPLC) in the evaluation of hemoglobinopathies. METHODS: This was a retrospective study using 174 whole blood samples encompassing the 5 most common (Hb A, A2', S, C, and E) and 10 rare (Hb G(Philidelphia), D, H, Bart's, O(Arab), S/G(Philidelphia), Hasharoon, Q(India), N(Baltimore), and Malmo) hemoglobin variants. An additional 126 samples were used to establish a CE reference interval for Hb A2. RESULTS: Hb A measurements agreed well between the 2 methods (bias=-0.06;r=0.999). The agreement of Hb F was also very good (bias=-0.17; r=0.994). When samples with the highest Hb F concentration were excluded, agreement was less precise (bias=-0.44; r=0.811). When no variant was present, the Hb A2 concentrations showed excellent agreement (bias=0.00; r=0.994). Positive bias for Hb A2 is seen when Hb C is present using CE. The Hb A2 reference interval using CE was <3.2%. CONCLUSION: The Capillarys Flex is capable of identifying and quantifying hemoglobin species, consistent with existing HPLC methods.

Hemoglobins S and C interfere with actin remodeling in Plasmodium falciparum-infected erythrocytes.

The hemoglobins S and C protect carriers from severe Plasmodium falciparum malaria. Here, we found that these hemoglobinopathies affected the trafficking system that directs parasite-encoded proteins to the surface of infected erythrocytes. Cryoelectron tomography revealed that the parasite generated a host-derived actin cytoskeleton within the cytoplasm of wild-type red blood cells that connected the Maurer's clefts with the host cell membrane and to which transport vesicles were attached. The actin cytoskeleton and the Maurer's clefts were aberrant in erythrocytes containing hemoglobin S or C. Hemoglobin oxidation products, enriched in hemoglobin S and C erythrocytes, inhibited actin polymerization in vitro and may account for the protective role in malaria.