Point-of-Care Screening for Sickle Cell Disease By a Mobile Micro-Electrophoresis Platform

Abstract

In developing countries, diagnostic tests for homozygous (HbSS) or compound heterozygous (HbSC or HbS-Beta thalassemia) sickle cell disease (SCD) are not readily available at the point-of-care (POC). Very few infants are screened in Africa for SCD because of the high cost and level of skill needed to run traditional tests. Current methods are too costly and take too much time to enable equitable and timely diagnosis to save lives. The World Health Organization recognizes a crucial need for early detection of SCD in newborns, since it is estimated that 70% SCD-related deaths in Africa are preventable with early cost-effective interventions. The diagnostic barrier can be broken with affordable, POC tools that facilitate early detection immediately after birth. We have developed a mobile micro-electrophoretic device (HemeChip) through which to quickly, accurately, and affordably screen for SCD (Fig. 1A). The HemeChip uses a microfabricated platform housing cellulose acetate electrophoresis to rapidly separate hemoglobin (Hb) types. Less than 5 microliters of blood, which can be obtained through a finger stick or heel stick, is processed on a piece of cellulose paper in alkaline buffer. The HemeChip reliably identifies and discriminates amongst Hb C/A2, S, F and A0. The micro-electrophoresis results were validated against standard clinical hemoglobin screening methods, including high performance liquid chromatography (HPLC), with Pearson Correlation Coefficient (PCC) of ≥0.96 relative to HPLC for all Hb types tested. The receiver Operating-Characteristic (ROC) curves showed more than 0.89 sensitivity and 0.86 specificity for identification of hemoglobin types using the HemeChip, based on the travelling distance from the sample application point (Fig. 1B). We developed a web-based image processing application for automated and objective quantification of HemeChip results at the POC using cloud computing resources (Fig. 1C). This intensity-based mobile phone image quantitation method showed high correlation with HPLC results for tested patient blood samples (PCC=0.95). HemeChip can distinguish between different patient phenotypes, including HbSS (HbS only), transfused HbSS (HbS and HbA), and Hemoglobin SC disease (HbS and HbC). In conclusion, the HemeChip identification and quantification of hemoglobin phenotypes, as a POC technique, were comparable to standard clinical methods. This platform has clinical potential in under-served populations worldwide, in which SCD is endemic. Figure 1. Mobile micro-electrophoretic device (HemeChip) for point-of-care screening for sickle cell disease. ( A) HemeChip prototype is shown with a miniscule blood sample that has been separated into characteristic hemoglobin bands. (B) The receiver Operating-Characteristic (ROC) curves show sensitivity and specificity of HemeChip for differentiating between adjacent hemoglobin bands based on the travelling distance from the sample application point. band traveling distance thresholds are shown: circle=7.5 mm, triangle=10.0 mm, and square=12.5 mm. (C) Web-based image processing application for automated and objective quantification of HemeChip results at the POC using cloud computing resources. Figure 1. Mobile micro-electrophoretic device (HemeChip) for point-of-care screening for sickle cell disease. ( A) HemeChip prototype is shown with a miniscule blood sample that has been separated into characteristic hemoglobin bands. (B) The receiver Operating-Characteristic (ROC) curves show sensitivity and specificity of HemeChip for differentiating between adjacent hemoglobin bands based on the travelling distance from the sample application point. band traveling distance thresholds are shown: circle=7.5 mm, triangle=10.0 mm, and square=12.5 mm. (C) Web-based image processing application for automated and objective quantification of HemeChip results at the POC using cloud computing resources. Disclosures No relevant conflicts of interest to declare.

Dynamic pH and Thermal Analysis of Paper-Based Microchip Electrophoresis

“…We have previously developed the first mass-producible, paper-based microchip electrophoresis (HemeChip) system for separation, identification, and quantification of various subtypes of hemoglobin variants for screening and diagnosing hemoglobin disorders (e.g., sickle cell disease) [7,[17][18][19][20][21][22][23]. Particularly in sickle cell disease (SCD), polymerization of hemoglobin S makes red blood cells stiff, which triggers abnormal cellular adhesion on inflamed vascular walls and the hallmark vaso-occlusive crisis [24][25][26][27][28].…”

Evaluation of Paper-Based Point of Care Screening Test for Sickle Cell Disease

“…HemeChip diagnostic system (Hemex Health Inc., Portland, OR) is another point of care device based on microchip electrophoresis assay. HemeChip separates hemoglobin variants on a piece of paper that is housed in a micro-engineered chip with a controlled environment and electric field [12,13]. The advantage of HemeChip diagnostic system is that it can detect and quantitate different hemoglobin variants HbA, HbS, HbF, HbA 2 and HbC as well.…”

Trends in the Development of Diagnostic Tools for Red Blood Cell-Related Diseases and Anemias

“…It is worthwhile to mention that most point of care devices work completely non-invasive or at least only require such small amounts of blood that can be taken by finger prick avoiding venous puncture (e.g., Pandey et al, 2018). Examples of early developments of smartphone-based diagnostic devices in conjunction with an "App" and appropriate sensors have been described for the detection of sickle cell disease (Knowlton et al, 2015;Ung et al, 2015), although not all point of care diagnostic devices are smartphone based. Promising recent developments are the HemoTypeSC to determine the hemoglobin types by Silver Lake Research (Azusa, CA, United States) (e.g., Nankanja et al, 2019;Steele et al, 2019;Mukherjee et al, 2020) or Sickle SCAN with a similar application by BioMedomics (Morrisville, NC, United States) (Nguyen-Khoa et al, 2018).…”