Validation and performance of MicroVue sC5b-9 Plus ELISA on the Dynex DS2 platform

• Published in: Clinica chimica acta Vol. 568; p. 120127
• Main Authors: Wilson, Rebecca J., Bhandari, Marcy, Dickerson, Jane A., Johnson, Lisa M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.02.2025
• Subjects: Adult; Complement Membrane Attack Complex - analysis; Eculizumab; ELISA; Enzyme-Linked Immunosorbent Assay - methods; Female; Humans; Male; Middle Aged; sC5b-9; TA-TMA; Thrombotic Microangiopathies - blood; Thrombotic Microangiopathies - diagnosis; Eculizumab; TA-TMA; sC5b-9; ELISA
• ISSN: 0009-8981; 1873-3492; 1873-3492
• DOI: 10.1016/j.cca.2025.120127

•This study validates the Quidel Microvue sC5b-9 Plus Assay for early detection of transplant-associated thrombotic microangiopathy in stem cell transplant recipients.•The assay exhibited reliable precision, and linearity, proving effective in identifying elevated sC5b-9 levels, a marker of TA-TMA risk.•Early identification of at-risk patients enables timely eculizumab treatment, improving outcomes and reducing healthcare costs. The complement membrane attack complex involves C5b-mediated assembly of C6-C9 polymers to form pores in cell membranes during complement activation. Inactive complexes can become soluble C5b-9 (sC5b-9) when they bind to Protein S. Elevated sC5b-9 levels are associated with increased risk of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), a serious condition which can be improved with eculizumab therapy. Early detection of TA-TMA is essential for improving patient outcomes and optimizing the use of this costly treatment. We assessed the Quidel Microvue sC5b-9 Plus Enzyme Immunoassay on the Dynex-DS2 platform to screen for patients at risk of TA-TMA. EDTA plasma samples were collected from bone marrow transplant (BMT) patients and others not at risk for TA-TMA. Assay validation included correlation with another laboratory, precision, linearity, and hemolysis interference. Additionally, clinical accuracy was assessed through retrospective patient data analyses. The assay showed acceptable intra- and interday precision, with less than 13 % variation. Linearity ranged from 80 to 1600 ng/mL, and there was no hemolysis interference up to 800 mg/dL. Clinical data revealed that monitoring sC5b-9 levels could detect significant increases indicative of TA-TMA, facilitating timely eculizumab intervention. Analytically, changes in sC5b-9 by 2- to 3-fold were significant for patient monitoring of TA-TMA. Lastly, a retrospective analysis on utility of the assay demonstrated effective utilization at our institution. The Quidel Microvue sC5b-9 Plus Enzyme Immunoassay demonstrated good analytical and clinical performance in screening patients with increased risk of TA-TMA.