Point-of-care microchip electrophoresis for integrated anemia and hemoglobin variant testing

Point-of-care diagnostic test accuracy in children and adolescents with sickle cell disease: A systematic review and meta-analysis

BACKGROUND

Detection of sickle cell disease (SCD) could be improved with greater use of point-of-care testing (POCT). This review assessed the accuracy of POCTs for SCD in children and adolescents.

METHODS

We systematically searched EMBASE, PubMed, Cochrane libraries, registries and conference proceedings from inception to 28th February 2023. We included cross-sectional and case-control studies that tested for SCD using POCTs and reference tests in individuals aged 0-19. We conducted meta-analysis to assess sensitivity and specificity of individual POCTs.

FINDINGS

The review included 31 studies overall, with 20 covering lateral flow immunoassays (LFIAs) and four covering micro-engineered electrophoresis. When detecting homozygous SCD, the pooled sensitivity and specificity of the included LFIAs and micro-engineered electrophoresis POCTs was 92 % or higher in all individual meta-analyses. Sensitivities and specificities were also nearly 100 % when detecting haemoglobin SC disease for these POCTs.

INTERPRETATION

POCTs could be used to accurately diagnose SCD.

A multiplexed, allele-specific recombinase polymerase amplification assay with lateral flow readout for sickle cell disease detection

Isothermal nucleic acid amplification tests have the potential to improve disease diagnosis at the point of care, but it remains challenging to develop multiplexed tests that can detect ≥3 targets or to detect point mutations that may cause disease. These capabilities are critical to enabling informed clinical decision-making for many applications, such as sickle cell disease (SCD). To address this, we describe the development of a multiplexed allele-specific recombinase polymerase amplification (RPA) assay with lateral flow readout. We first characterize the specificity of RPA using primer design strategies employed in PCR to achieve point mutation detection, and demonstrate the utility of these strategies in achieving selective isothermal amplification and detection of genomic DNA encoding for the healthy βA globin allele, or genomic DNA containing point mutations encoding for pathologic βS and βC globin alleles, which are responsible for most sickle cell disorders. We then optimize reaction conditions to achieve multiplexed amplification and identification of the three alleles in a single reaction. Finally, we perform a small pilot study with 20 extracted genomic DNA samples from SCD patients and healthy volunteers - of the 13 samples with valid results, the assay demonstrated 100% sensitivity and 100% specificity for detecting pathologic alleles, and an overall accuracy of 92.3% for genotype prediction. This multiplexed assay is rapid, minimally instrumented, and when combined with point-of-care sample preparation, could enable DNA-based diagnosis of SCD in low-resource settings. The strategies reported here could be applied to other challenges, such as detection of mutations that confer drug resistance.

Microstrip isoelectric focusing with deep learning for simultaneous screening of diabetes, anemia, and thalassemia

BACKGROUND

Hemoglobin (Hb) is an important protein in red blood cells and a crucial diagnostic indicator of diseases, e.g., diabetes, thalassemia, and anemia. However, there is a rare report on methods for the simultaneous screening of diabetes, anemia, and thalassemia. Isoelectric focusing (IEF) is a common separative tool for the separation and analysis of Hb. However, the current analysis of IEF images is time-consuming and cannot be used for simultaneous screening. Therefore, an artificial intelligence (AI) of IEF image recognition is desirable for accurate, sensitive, and low-cost screening.

RESULTS

Herein, we proposed a novel comprehensive method based on microstrip isoelectric focusing (mIEF) for detecting the relative content of Hb species. There was a good coincidence between the quantitation of Hb via a conventional automated hematology analyzer and the one via mIEF with R2 = 0.9898. Nevertheless, our results showed that the accuracy of disease diagnosis based on the quantification of Hb species alone is as low as 69.33 %, especially for the simultaneous screening of multiple diseases of diabetes, anemia, alpha-thalassemia, and beta-thalassemia. Therefore, we introduced a ResNet1D-based diagnosis model for the improvement of screening accuracy of multiple diseases. The results showed that the proposed model could achieve a high accuracy of more than 90 % and a good sensitivity of more than 96 % for each disease, indicating the overwhelming advantage of the mIEF method combined with deep learning in contrast to the pure mIEF method.

SIGNIFICANCE

Overall, the presented method of mIEF with deep learning enabled, for the first time, the absolute quantitative detection of Hb, relative quantitation of Hb species, and simultaneous screening of diabetes, anemia, alpha-thalassemia, and beta-thalassemia. The AI-based diagnosis assistant system combined with mIEF, we believe, will help doctors and specialists perform fast and precise disease screening in the future.

Differential sensitivity to hypoxia enables shape-based classification of sickle cell disease and trait blood samples at point of care

Red blood cells (RBCs) become sickle-shaped and stiff under hypoxia as a consequence of hemoglobin (Hb) polymerization in sickle cell anemia. Distinguishing between sickle cell disease and trait is crucial during the diagnosis of sickle cell disease. While genetic analysis or high-performance liquid chromatography (HPLC) can accurately differentiate between these two genotypes, these tests are unsuitable for field use. Here, we report a novel microscopy-based diagnostic test called ShapeDx™ to distinguish between disease and trait blood in less than 1 h. This is achieved by mixing an unknown blood sample with low and high concentrations of a chemical oxygen scavenger and thereby subjecting the blood to slow and fast hypoxia, respectively. The different rates of Hb polymerization resulting from slow and fast hypoxia lead to two distinct RBC shape distributions in the same blood sample, which allows us to identify it as healthy, trait, or disease. The controlled hypoxic environment necessary for differential Hb polymerization is generated using an imaging microchamber, which also reduces the sickling time of trait blood from several hours to just 30 min. In a single-blinded proof-of-concept study conducted on a small cohort of clinical samples, the results of the ShapeDx™ test were 100% concordant with HPLC results. Additionally, our field studies have demonstrated that ShapeDx™ is the first reported microscopy test capable of distinguishing between sickle cell disease and trait samples in resource-limited settings with the same accuracy as a gold standard test.

Metabolite and protein shifts in mature erythrocyte under hypoxia

As the only cell type responsible for oxygen delivery, erythrocytes play a crucial role in supplying oxygen to hypoxic tissues, ensuring their normal functions. Hypoxia commonly occurs under physiological or pathological conditions, and understanding how erythrocytes adapt to hypoxia is fundamental for exploring the mechanisms of hypoxic diseases. Additionally, investigating acute and chronic mountain sickness caused by plateaus, which are naturally hypoxic environments, will aid in the study of hypoxic diseases. In recent years, increasingly developed proteomics and metabolomics technologies have become powerful tools for studying mature enucleated erythrocytes, which has significantly contributed to clarifying how hypoxia affects erythrocytes. The aim of this article is to summarize the composition of the cytoskeleton and cytoplasmic proteins of hypoxia-altered erythrocytes and explore the impact of hypoxia on their essential functions. Furthermore, we discuss the role of microRNAs in the adaptation of erythrocytes to hypoxia, providing new perspectives on hypoxia-related diseases.

Point-of-Care Diagnostic Test for Beta-Thalassemia

Hemoglobin (Hb) disorders are among the most common monogenic diseases affecting nearly 7% of the world population. Among various Hb disorders, approximately 1.5% of the world population carries β-thalassemia (β-Thal), affecting 40,000 newborns every year. Early screening and a timely diagnosis are essential for β-thalassemia patients for the prevention and management of later clinical complications. However, in Africa, Southern Europe, the Middle East, and Southeast Asia, where β-thalassemia is most prevalent, the diagnosis and screening for β-thalassemia are still challenging due to the cost and logistical burden of laboratory diagnostic tests. Here, we present Gazelle, which is a paper-based microchip electrophoresis platform that enables the first point-of-care diagnostic test for β-thalassemia. We evaluated the accuracy of Gazelle for the β-Thal screening across 372 subjects in the age range of 4-63 years at Apple Diagnostics lab in Mumbai, India. Additionally, 30 blood samples were prepared to mimic β-Thal intermediate and β-Thal major samples. Gazelle-detected levels of Hb A, Hb F, and Hb A2 demonstrated high levels of correlation with the results reported through laboratory gold standard high-performance liquid chromatography (HPLC), yielding a Pearson correlation coefficient = 0.99. This ability to obtain rapid and accurate results suggests that Gazelle may be suitable for the large-scale screening and diagnosis of β-Thal.

Diagnosis and screening of abnormal hemoglobins

Hemoglobin (Hb) abnormalities, such as thalassemia and structural Hb variants, are among the most prevalent inherited diseases and are associated with significant mortality and morbidity worldwide. However, there were not comprehensive reviews focusing on different clinical analytical techniques, research methods and artificial intelligence (AI) used in clinical screening and research on hemoglobinopathies. Hence the review offers a comprehensive summary of recent advancements and breakthroughs in the detection of aberrant Hbs, research methods and AI uses as well as the present restrictions anddifficulties in hemoglobinopathies. Recent advances in cation exchange high performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE), isoelectric focusing (IEF), flow cytometry, mass spectrometry (MS) and polymerase chain reaction (PCR) etc have allowed for the definitive detection by using advanced AIand portable point of care tests (POCT) integrating with smartphone microscopic classification, machine learning (ML) model, complete blood counts (CBC), imaging-based method, speedy immunoassay, and electrochemical-, microfluidic- and sensing-related platforms. In addition, to confirm and validate unidentified and novel Hbs, highly specialized genetic based techniques like PCR, reverse transcribed (RT)-PCR, DNA microarray, sequencing of genomic DNA, and sequencing of RT-PCR amplified globin cDNA of the gene of interest have been used. Hence, adequate utilization and improvement of available diagnostic and screening technologies are important for the control and management of hemoglobinopathies.

Inherited disorders of hemoglobin: A review of old and new diagnostic methods

The genetic regulation of hemoglobin is complex and there are a number of genetic abnormalities that result in clinically important hemoglobin disorders. Here, we review the molecular pathophysiology of hemoglobin disorders and review both old and new methods of diagnosing these disorders. Timely diagnosis of hemoglobinopathies in infants is essential to coordinate optimal life-saving interventions, and accurate identification of carriers of deleterious mutations allows for genetic counseling and informed family planning. The initial laboratory workup of inherited disorders of hemoglobin should include a complete blood count (CBC) and peripheral blood smear, followed by carefully selected tests based on clinical suspicion and available methodology. We discuss the utility and limitations of the various methodologies to fractionate hemoglobin, including cellulose acetate and citrate agar hemoglobin electrophoresis, isoelectric focusing, high-resolution high-performance liquid chromatography, and capillary zone electrophoresis. Recognizing that most of the global burden of hemoglobin disorders exists in low- and middle-income countries, we review the increasingly available array of point-of-care-tests (POCT), which have an increasingly important role in expanding early diagnosis programs to address the global burden of sickle cell disease, including Sickle SCAN, HemoTypeSC, Gazelle Hb Variant, and Smart LifeLC. A comprehensive understanding of the molecular pathophysiology of hemoglobin and the globin genes, as well as a clear understanding of the utility and limitations of currently available diagnostic tests, is essential in reducing global disease burden.

A pH-mediated field amplification sample stacking technique based on portable microchip electrophoresis heavy metal ion detection system

We built a portable microchip electrophoresis heavy metal ion detection system and proposed a pH-mediated field amplified sample stacking (pH-mediated FASS) online preconcentration method. The pH-mediated FASS focuses and stacks heavy metal cations by controlling electrophoretic mobilities with a pH change between the analyte and the background electrolyte (BGE) in solution to improve the detection sensitivity of the system. We optimized and adjusted sample matrix solution (SMS) ratios and pH to create concentration and pH gradients for SMS and BGE. Furthermore, we optimize the microchannel width to improve the preconcentration effect further. The system and method analyzed soil leachates polluted with heavy metals and separated Pb2+ and Cd2+ within 90 s, obtaining their levels at 58.01 mg/L and 4.91 mg/L with sensitivity enhancement factors (SEF) of 26.40 and 43.73. Compared with inductively coupled plasma atomic emission spectrometry (ICP-AES), the detection error of the system was less than 8.80%.

Catch bonds in sickle cell disease: Shear-enhanced adhesion of red blood cells to laminin

Could the phenomenon of catch bonding-force-strengthened cellular adhesion-play a role in sickle cell disease, where abnormal red blood cell (RBC) adhesion obstructs blood flow? Here, we investigate the dynamics of sickle RBCs adhering to a surface functionalized with the protein laminin (a component of the extracellular matrix around blood vessels) under physiologically relevant microscale flow. First, using total internal reflectance microscopy we characterize the spatial fluctuations of the RBC membrane above the laminin surface before detachment. The complex dynamics we observe suggest the possibility of catch bonding, where the mean detachment time of the cell from the surface initially increases to a maximum and then decreases as a function of shear force. We next conduct a series of shear-induced detachment experiments on blood samples from 25 sickle cell disease patients, quantifying the number and duration of adhered cells under both sudden force jumps and linear force ramps. The experiments reveal that a subset of patients does indeed exhibit catch bonding. By fitting the data to a theoretical model of the bond dynamics, we can extract the mean bond lifetime versus force for each patient. The results show a striking heterogeneity among patients, both in terms of the qualitative behavior (whether or not there is catch bonding) and in the magnitudes of the lifetimes. Patients with large bond lifetimes at physiological forces are more likely to have certain adverse clinical features, like a diagnosis of pulmonary arterial hypertension and intracardiac shunts. By introducing an in vitro platform for fully characterizing RBC-laminin adhesion dynamics, our approach could contribute to the development of patient-specific antiadhesive therapies for sickle cell disease. The experimental setup is also easily generalizable to studying adhesion dynamics in other cell types, for example, leukocytes or cancer cells, and can incorporate disease-relevant environmental conditions like oxygen deprivation.

A Novel Approach for Glycosylated Hemoglobin Testing Using Microchip Affinity Electrophoresis

OBJECTIVE

Effective management of diabetes largely benefits from early diagnosis followed by intensive long-term regulation of blood glucose. The levels of glycohemoglobin (HbA1 and HbA1c) have been used as standard biomarkers to assess long-term blood glucose concentrations for diabetes diagnosis and management. Gold standard laboratory methods for HbA1 and HbA1c testing are often costly and not widely available. Moreover, currently available point-of-care (POC) immunoassay-based glycohemoglobin tests may produce inaccurate test results for patients with co-existing diseases such as hemoglobin disorders and anemia. Here, we report a POC platform, HemeChip-GHb, for quantitative HbA1 detection leveraging paper-based affinity electrophoresis.

METHODS

We describe the design and development of the HemeChip-GHb test. Feasibility and accuracy of the HemeChip-GHb system were demonstrated by testing blood samples collected from healthy donors, patients with prediabetes, and patients with diabetes.

RESULTS

HbA1 levels measured with HemeChip-GHb show 0.96 correlation to the levels reported from the clinical standard HPLC tests, and with a bias of -0.72% based on Bland-Altman analysis. 99.6% of the HbA1 levels for paired HemeChip-GHb and HPLC fell within A and B zones of no difference in clinical outcome based on error grid analysis.

CONCLUSION

Using HemeChip-GHb we achieved accurate diabetes status detection with sensitivity and specificity of 100%.

SIGNIFICANCE

We presented a novel POC paper-based affinity electrophoresis platform that has the potential for accurately diagnosing diabetes, and addressing an unmet need for accurate and affordable diagnostics in resource-challenged environments.

Last Trends in Point-of-Care (POC) Diagnostics for the Management of Hematological Indices in Home Care Patients

Today, complete blood count (CBC) analyses are highly automated and allow for high throughput and accurate and reliable results. However, new analytical tools are in great demand to provide simple, rapid and cost-effective management of hematological indices in home care patients. Chronic disease monitoring at home has become a benefit for patients who are finding cost savings in programs designed to monitor/treat patients in offsite locations. This review reports the latest trends in point-of-care (POC) diagnostics useful for home testing of key hematological counts that may be affected during home therapy treatment.

A retrospective case study of successful translational research: Gazelle Hb variant point-of-care diagnostic device for sickle cell disease

Evaluation researchers at Clinical and Translational Science Award (CTSA) hubs are conducting retrospective case studies to evaluate the translational research process. The objective of this study was to deepen knowledge of the translational process and identify contributors to successful translation. We investigated the successful translation of the HemeChip, a low-cost point-of-care diagnostic device for sickle cell disease, using a protocol for retrospective translational science case studies of health interventions developed by evaluators at the National Health Institutes (NIH) and CTSA hubs. Development of the HemeChip began in 2013 and evidence of device use and impact on public health is growing. Data collection methods included five interviews and a review of press, publications, patents, and grants. Barriers to translation included proving novelty, manufacturing costs, fundraising, and academic-industry relations. Facilitators to translation were CTSA pilot program funding, university resources, entrepreneurship training, due diligence, and collaborations. The barriers to translation, how they were overcome, and the key facilitators identified in this case study pinpoint areas for consideration in future funding mechanisms and the infrastructure required to enable successful translation.