Clinical Utility of Recently FDA Approved IntelliSep test (Sepsis biomarker) for early Diagnosis of Sepsis: Comparison with other Biomarkers and von Willebrand Factor/ADAMTS13 Ration

Abstract

Abstract Background Sepsis, a relatively common presentation in emergency departments, is a life-threatening disease. Recently, IntelliSep test by Cytovale (San Francisco, CA) received FDA approval as sepsis biomarker. We investigated clinical utility of this test using 44 patients (19 disease group and 25 non-disease group). Materials and Methods IntelliSep assesses cellular host response via deformability cytometry of leukocyte biophysical properties and intended for use in conjunction with clinical assessments and laboratory findings for early detection of sepsis. Test results are available within 10 minutes. Results consists of IntelliSep Band 1 (low risk, score: 0.1-4.9) to Band 3 (high risk, score: 6.3-10; total scale: 0.1-10). We measured IntelliSep score in 44 patients using EDTA blood. Left over plasma was used for measuring both plasma von Willebrand factor (vWF) antigen and ADAMTS13 antigen by ELISA assays. Monocyte distribution width (MDW) were obtained during routine CBC analysis using Beckman hematology analyzer. Lactate and high sensitivity troponin I were measured using Beckman analyzer. Results The median IntelliSep score was two-fold higher in the disease group (mean score 7.1, SD: 1.5, median: 7.4) compared to non-disease group (mean score 4.0, SD: 1.4, Median: 3.7) indicating that this new test can identify patients with high risk of developing sepsis and also rule out low risk patients (p<0.01 by both Mann-Whitney U test two tailed and t-test two tailed). The median MDW was also 34.8 % higher in the disease group (mean:25.6, SD: 5.0, Median: 24.4) compared to non-disease group (mean: 18.9, SD: 2.4, Median: 18.1) and difference was also statistically significant (p < 0.01 by both Mann-Whitney U test and t-test, two tailed). However, correlation between IntelliSep scores and MDW was only modest (overall, r= 0.66). Both lactate and procalcitonin concentrations were significantly higher in the disease group compared to the non-disease group. Interestingly, high-sensitivity troponin I concentrations were also significantly higher in the disease group. In addition, we observed significantly higher plasma vWF antigen in the disease group compared to the non-disease group (mean: 67.4 ug/mL in disease group vs 34.1 ug/mL in the non-disease group. However, in some patients in the disease group plasma vWF values were 6.8-fold higher than normal. In addition, vWF/ADAMTS13 ratio was also significantly elevated in the disease group compared to non-disease group. Discussion New IntelliSep test is useful in early prediction of sepsis in patients admitted to emergency department and may be superior to MDW and lactate for early diagnosis. Significant increase in plasma vWF in these patients indicate that vWF may also be a surrogate marker for endotheliopathy in sepsis. Lack of correlation between plasma VWF and Intellisep results indicates that these two markers probably measure different pathways for sepsis (endothelial activation vs neutrophil activation).