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Diagnostic tests that detect antibodies (AB) against SARS-CoV-2 for evaluation of seroprevalence and guidance of health care measures are important tools for managing the COVID-19 pandemic. Current tests have certain limitations with regard to turnaround time, costs and availability, particularly in point-of-care (POC) settings. We established a hemagglutination-based AB test that is based on bi-specific proteins which contain a dromedary-derived antibody (nanobody) binding red blood cells (RBD) and a SARS-CoV-2-derived antigen, such as the receptor-binding domain of the Spike protein (Spike-RBD). While the nanobody mediates swift binding to RBC, the antigen moiety directs instantaneous, visually apparent hemagglutination in the presence of SARS-CoV-2-specific AB generated in COVID-19 patients or vaccinated individuals. Method comparison studies with assays cleared by emergency use authorization demonstrate high specificity and sensitivity. To further increase objectivity of test interpretation, we developed an image analysis tool based on digital image acquisition (via a cell phone) and a machine learning algorithm based on defined sample-training and -validation datasets. Preliminary data, including a small clinical study, provides proof of principle for test performance in a POC setting. Together, the data support the interpretation that this AB test format, which we refer to as 'NanoSpot.ai', is suitable for POC testing, can be manufactured at very low costs and, based on its generic mode of action, can likely be adapted to a variety of other pathogens., (© 2021. The Author(s).)

A stool and serosurvey for Strongyloides stercoralis was conducted in a community in the Peruvian Amazon region. Strongyloidiasis stercoralis was identified in the stool of 69 (8.7%) of 792 participants. Six hundred nine sera were tested using by an enzyme-linked immunosorbent assay (ELISA), which had a sensitivity of 92% and a specificity of 94%; 442 (72%) were positive. In multivariable logistic regression models, having S. stercoralis in stool was associated with hookworm in the same specimen (odds ratio [OR] = 4.44, 95% confidence interval [CI] = 2.02-9.79), occasionally or never wearing shoes (OR = 1.89, 95% CI = 1.10-3.27), and increasing age (OR = 1.012 for each one-year increase, 95% CI = 1.00-1.03). Similarly, occasionally or never wearing shoes (OR = 1.54, 95% CI = 1.01-2.37) and increasing age (OR = 1.04 for each one-year increase, 95% CI = 1.02-1.06) were associated with an increased risk of a positive S. stercoralis ELISA result. The ELISA had a negative predictive value of 98% and is an excellent screening test for strongyloidiasis.

Objective: This research used a study-control group design and examined data collected from five hospitals to evaluate the effectiveness of retrospective peer-review systems on reducing utilization of red blood cells (RBCs)., Design: The effects of retrospective peer-review systems were studied in three parts: (1) trends of RBC utilization were compared by the slopes of linear regression lines that assessed the effect of time on RBC utilization among four study hospitals and one control hospital, (2) diagnosis-specific RBC utilization was compared between the control hospital and one matched study hospital, and (3) the effect of the retrospective review system of one study hospital was assessed by linear regression using data accumulated 1 year before and 2 years after implementation of the program., Results: Three study hospitals showed no significant changes in RBC utilization during the 10-month study period. One study hospital and the control hospital demonstrated trends of reduced RBC use with negative slopes of regression lines; however, there was no difference in the degree of the two slopes, and the diagnosis-specific RBC utilization was not lower at the study hospital than at the control hospital. Furthermore, implementation of the retrospective peer-review system at one study hospital demonstrated no effect on RBC utilization., Conclusions: We conclude that the retrospective peer-review systems implemented at these four hospitals had no effect on reducing red blood cell utilization.