Ultrasensitive Flow-based Immunoassays Using Single-Molecule Counting

• Published in: Clinical chemistry (Baltimore, Md.) Md.), 2007-11, Vol.53 (11), p.1990-1995
• Main Authors: Todd, John, Freese, Bob, Lu, Ann, Held, Douglas, Morey, Jennifer, Livingston, Richard, Goix, Philippe
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Biomarkers - blood; Blood banks; Detection limits; Dogs; Erenna; Fundamental and applied biological sciences. Psychology; Haplorhini; Humans; Immunoassay; Immunoassay - methods; Immunoassays; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Performance assessment; Plasma; Proteins; Rats; Reproducibility of Results; Sensitivity and Specificity; Technical support; Troponin I - blood
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1373/clinchem.2007.091181

Immunoassay (IA) technology has expanded the clinical utility of protein biomarkers, but demands for increased sensitivity, dynamic reporting ranges, and small sample volumes have limited the potential clinical usefulness of many biomarkers. We assessed the performance, including limits of detection (LODs) and the dynamic reporting range, of an IA-based technology, Erenna Immunoassay System, for a series of biomarkers, including cardiac troponin I (cTnI). Erenna IAs were used with 10 different and clinically important biomarkers to ascertain the LOD with various sample sizes (10 microL to 200 microL). The Erenna Immunoassay System generated LODs of 10-100 pg/L using 100 microL of sample. For cTnI, the LOD was 0.2 ng/L and a 10% CV was seen between 0.78 and 1.6 ng/L. The Erenna IA-based technology reproducibly measures protein biomarkers with detection limits of 10-100 pg/L, with a dynamic range of >4.5 logs in sample volumes of 50-150 microL.