Figure 10

Performance, dynamic range, and reproducibility of the ECL-based IA assay across three independent test sites. Plasma samples from 59 non-diabetic individuals (30 males, 29 females, Mean Age: 28.61 ± 8 yr) and serum samples from 34 long-standing diabetic individuals (11 males, 21 females, Mean Age: 38.23 ± 15.73) were evaluated using our human IA ECL-assay at three separate laboratories. A) IA values from all samples were analyzed by receiver operating characteristic (ROC) analysis for the ability to distinguish between non-diabetic and diabetic donors. B) Plot of mean values obtained across the three test sites for each sample. Samples could be distinguished by IA values spanning a 3-log range (0.77-943.3). A cutoff IA value of 3.0 (dashed line) determined by ROC analysis of these samples. C) Plot of ascending intra-laboratory rank vs ascending mean rank for the 93 samples across the three test sites. Samples were ranked 1 through 93 in order of increasing IA value as determined by our IA ECL assay. Black circles = Lab 1 (Wellstat), black squares = Lab 2 (NIAID), and black triangles = Lab 3 (DIL). All statistical analyses were performed using Prism software. *AUC, Area under the curve;^† 95% CI, 95% confidence interval; AS95 = sensitivity at 95% specificity; Lab1-Wellstat = Wellstat Diagnostics in Gaithersburg, MD, USA. Lab2-NIAID = Laboratory of Immunology, National Institute of Allergy and Infectious Disease in Bethesda, MD, USA; and Lab3-DIL = Diabetes and Inflammation Laboratory, University of Cambridge in Cambridge, UK.