Rapid detection of SARS-CoV-2 antibodies using electrochemical impedance-based detector

Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was classified as a pandemic by the World Health Organization and has caused over 550,000 deaths worldwide as of July 2020. Accurate and scalable point-of-care devices would increase screening, diagnosis, and monitoring of COVID-19 patients. Here, we demonstrate rapid label-free electrochemical detection of SARS-CoV-2 antibodies using a commercially available impedance sensing platform. A 16-well plate containing sensing electrodes was pre-coated with receptor binding domain (RBD) of SARS-CoV-2 spike protein, and subsequently tested with samples of anti-SARS-CoV-2 monoclonal antibody CR3022 (0.1 μg/ml, 1.0 μg/ml, 10 μg/ml). Subsequent blinded testing was performed on six serum specimens taken from COVID-19 and non-COVID-19 patients (1:100 dilution factor). The platform was able to differentiate spikes in impedance measurements from a negative control (1% milk solution) for all CR3022 samples. Further, successful differentiation and detection of all positive clinical samples from negative control was achieved. Measured impedance values were consistent when compared to standard ELISA test results showing a strong correlation between them (R2=0.9). Detection occurs in less than five minutes and the well-based platform provides a simplified and familiar testing interface that can be readily adaptable for use in clinical settings.

Development of a multiplex fully automated assay for rapid quantification of CD4+ T cells from whole blood

The development of cost-effective and rapid assays for the accurate counting of CD4 cells has remained prime focus for disease management. The lack of such assays has severely affected people living in resource-limited disease prevalent areas. CD4 count information plays a vital role in the effective management of HIV disease. There is an unmet need to develop rapid, cost-effective, portable and user-friendly point-of-care (POC) disease diagnostic platform technology for CD4+ T cell counting. Here, we have developed a flow-free magnetic actuation platform that uses antibody-coated magnetic beads to efficiently capture CD4+ T cells from a 30 μL drop of whole blood. On-chip cell lysate electrical impedance spectroscopy has been utilized to quantify the isolated CD4 cells. The developed assay has a limit of detection of 25 cells per μL and provides accurate CD4 counts in the range of 25-800 cells per μL. The whole immunoassay along with the enumeration process is very rapid and provides CD4 quantification results within 5 min time frame. The assay does not require off-chip sample preparation steps and minimizes human involvement to a greater extent. The developed impedance-based immunoassay has potential to significantly improve the CD4 enumeration process especially for POC settings.

Economic benefits of BIS-aided assessment of post-BC lymphedema in the United States

OBJECTIVES

To estimate the economic outcomes associated with routine use of bioimpedance spectroscopy (BIS) to aid in the assessment of lymphedema following breast cancer (BC) treatment.

STUDY DESIGN

Budget impact analysis for a hypothetical payer, comparing a "current standard assessment methods" scenario with a hypothetical scenario in which BIS is used routinely.

METHODS

A payer-perspective decision model was built to calculate the 1-year budget impact of using either current standard methods or BISaided assessments for lymphedema in post-BC patients among a hypothetical payer population. Parameter values were obtained from the medical literature, including population characteristics, lymphedema incidence, resource utilization, and costs associated with assessments and treatment. Alternate scenario analysis incorporated incidence and associated costs of downstream infections and excess mental health care.

RESULTS

With 627 BC patients in a payer of 1M covered lives, base-case analysis shows cost savings of $315,711, or $0.03 per enrolled member per month (from the payer perspective), from implementation of BIS-aided assessments for lymphedema. Savings improved with consideration of sequelae (eg, infection, hospitalization). However, savings are reduced if specificity of current standard assessments improves by 25% (fewer unnecessary expensive treatments), or if cost of complex decongestive therapy falls by 25%. Sensitivity analysis showed that cost savings results were robust to changes in other model parameters.

CONCLUSIONS

Over 1 year, BIS-aided assessment of lymphedema for patients following treatment for BC results in cost savings, even without considering potential cost savings associated with averted downstream sequelae.