B-277 Analytical Validation of Whole Blood Suitability for MeMed BV, A Host-protein Test for Differentiating Between Bacterial and Viral Infection

Abstract Background MeMed BV® is an FDA-cleared test for differentiating bacterial and viral infections. It is based on computational integration of serum levels of TNF-related apoptosis-induced ligand (TRAIL), interferon gamma-induced protein-10 (IP-10), and C-reactive protein (CRP). The test result is a score between 0 and 100 that correlates with increasing likelihood of bacterial infection (or co-infection). Here, we assessed the analytical performance of MeMed BV using whole blood (WB). Methods Precision for each BV analyte and the score were assessed using 3 clinical WB samples representing bacterial, viral and equivocal scores. Each specimen was analyzed in four runs on five MeMed Key® analyzers in accordance with CLSI EP05-A3 Evaluation of Precision of Quantitative Measurement Procedures. For the matrix comparison study, paired samples of serum and WB were collected from patients with suspected acute bacterial/viral infection. The study was performed in accordance with CLSI EP35Ed1E Assessment of Equivalence or Suitability of Specimen Types. Limit of Quantitation was established based on CLSI EP17-A2 Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures. Results Precision results passed the pre-determined acceptance criteria for the analytes and score. The precision coefficient of variation range was 4.6%–6.9%, 3.1%–5.8%, and 4.0%–12.0% for TRAIL, IP-10 and CRP, respectively. The precision standard deviation for the score was 0.0–3.0 score units. For the matrix comparison study, 216 patients were recruited, aged 1–92 years (median 42.0) and 45.8% female. Passing-Bablok regression analysis of test scores from serum vs WB yielded a slope of 1.00 (95% confidence interval, CI 0.99–1.00) and intercept of 0.00 (95%CI 0.00–0.06) fulfilling pre-defined acceptance criteria (Fig. 1). Limit of Quantitation was established to be 1mg/L, 100 pg/mL, and 15 pg/mL for CRP, IP-10 and TRAIL, respectively, the same values as for serum.Fig. 1. Conclusion Suitability of MeMed BV® for whole blood was demonstrated.