A Novel Implementation of Magnetic Levitation to Quantify Leukocyte Size, Morphology, and Magnetic Properties to Identify Patients With Sepsis

Background: We have developed a novel, easily implementable methodology using magnetic levitation to quantify circulating leukocyte size, morphology, and magnetic properties, which may help in rapid, bedside screening for sepsis. Objective: Our objectives were to describe our methodological approach to leukocyte assessment, and to perform a pilot investigation to test the ability of magnetic levitation to identify and quantify changes in leukocyte size, shape, density, and/or paramagnetic properties in healthy controls and septic patients. Methods: This prospective, observational cohort study was performed in a 56,000/y visit emergency department (ED) and affiliated outpatient phlebotomy laboratory. Inclusion criteria were admittance to the hospital with suspected or confirmed infection for the septic group, and we enrolled the controls from ED/outpatient patients without infection or acute illness. The bench-top experiments were performed using magnetic levitation to visualize the leukocytes. We primary sought to compare septic patients with noninfected controls and secondary to assess the association with sepsis severity. Our covariates were area, length, width, roundness, and standard deviation (SD) of levitation height. We used unpaired t test and area under the curve (AUC) for the assessment of accuracy in distinguishing between septic and control patients. Results: We enrolled 39 noninfected controls and 22 septic patients. Our analyses of septic patients compared with controls showed: mean cell area in pixels (px) 562 ± 111 vs. 410 ± 45, P < 0.0001, AUC = 0.89 (0.80–0.98); length (px), 29 ± 2.5 vs. 25 ± 1.9, P < 0.0001, AUC = 0.90 (0.83–0.98); and width (px), 27 ± 2.4 vs. 23 ± 1.5, P < 0.0001, AUC = 0.92 (0.84–0.99). Cell roundness: 2.1 ± 1.0 vs. 2.2 ± 1.2, P = 0.8, AUC = 0.51. SD of the levitation height (px) was 72 ± 25 vs. 47 ± 16, P < 0.001, AUC = 0.80 (0.67–0.93). Conclusions: Septic patients had circulating leukocytes with especially increased size parameters, which distinguished sepsis from noninfected patients with promising high accuracy. This portal-device compatible technology shows promise as a potential bedside diagnostic.