Abstract

A Troponin T Assay with Lab-like Performance at the Point-of-Care using a Novel Immunochemistry Platform

Eloisa Lopez-Calle, Research & Development Line Manager & Development Lead, Roche Diagnostics GmbH

A high sensitivity cardiac troponin T assay was developed on a new immunoassay platform technology for the determination of the analyte with lab-like performance. The assay was completely run in a ready-to-use plastic disposable, a centrifugal microfluidic disc, with fully integrated reagents required for the analysis, and the total assay time from sample application to result was 11 minutes. The disc consists of a plastic body containing structures for assay processing, a porous membrane and all dried immuno reagents. Additionally, a blister containing a washing buffer is implemented for performing repetitive bound-free separation steps. After sample application, 30µL of whole blood, the assay was automatically processed in the instrument, firstly by generating plasma via centrifugation, followed by incubation of a defined volume of the generated plasma with the immunoreagents. After washing, the fluorescence in the signal zone of the membrane was measured for the quantitation of cardiac troponin T.

For the proof-of-concept a dose-response curve, measured from whole blood samples spiked with native human cardiac troponin T, was generated covering a range up to a concentration of approx. 8000 ng/L which yielded a lower detection limit of 3.0 ng/L. The imprecision for 3 individual whole blood samples from different donors was determined to be 3.8% at a concentration level of 14 ng/L, the 99th percentile value from the high-sensitivity cardiac troponin T assay in the Elecsys® system,. An imprecision profile indicated that human cardiac troponin T is determinable with a functional sensitivity (CV <10%) of 6.8 ng/L. An excellent correlation with the high-sensitivity cardiac troponin T Elecsys® assay for 49 clinical plasma samples (r = 0.9744) was obtained.

The data shows that the analytical performance for the determination of cardiac troponin T with lab-like performance is achievable in a point-of-care setting. The superior performance was achieved by fully controlled steps in terms of time, volumes and temperature in a fleece-free test carrier. The presented assay technology can be applied to any kind of immunoassays where analytes require an elevated analytical performance.