Detection of Multiple Allergen-specific IgEs on Microarrays by Immunoassay with Rolling Circle Amplification

Abstract

limit (15 and 22 below the limits for the Stratus and Immulite assays, respectively) and 42 (12%) had both results below the respective detection limits. Regression analysis was performed on the 268 remaining samples: Immulite cTnI 1.84 (Stratus cTnI) 1.1 g/L; r 0.977; S yx 4.7 g/L. The high slope might result from a lack of standardization between cTnI assays (2 ) and/or a difference in the reactivities of the antibodies used to the various circulating forms of the protein (3-6 ). We routinely used an upper reference limit (URL) of 0.6 g/L for the Stratus cTnI assay. To estimate the corresponding value for the Immulite cTnI assay, we established the relationship between the two assays in 137 samples with Stratus cTnI values 5 g/L: Immulite cTnI 1.51 (Stratus cTnI) 0.27; r 0.924. The estimated Immulite URL (based on the regression) corresponding to a Stratus value of 0.6 g/L was 1.18 g/L (Fig. Using these cutoffs, we studied 80 patients admitted to the intensive care unit (37 with acute myocardial infarction, 22 with unstable angina, and 21 with chest pain). Heparinized samples were collected on admission. The Stratus (0.6 g/L) and estimated Immulite (1.18 g/L) URLs gave specificities of 93% [95% confidence interval (CI), 69.6 -98.8%] and 95% (95% CI, 76.2-99.9%), respectively, for acute coronary syndrome (vs 21 chest pain patients) and sensitivities of 95% (95% CI, 85.9 -98.9%) and 92% (95% CI, 81.3-97.2%), respectively.