ImageQuant: An image-based quantitative Immunoassay Analyzer

Abstract

Lateral flow immunoassay (LFIA) is popularly employed in point-of-care (PoC) diagnostics for quantitative estimation of a particular analyte present in a sample. Here, we present a compact, affordable and easy-to-use quantitative LFIA reader: ImageQuant Analyzer. This is an image-based analyzer for LFIA test kits. It gives a quantitative estimate of the target analyte — a good improvement over existing semi-quantitative or qualitative image-based LFIA readers. The instrument's hardware architecture and software are described in this paper. The Coefficient of Variation (CoV) for repeatability and reproducibility of the measurements was verified with four stable fluorescence cartridges. The CoV for repeatability test across all four reference cartridges was found to be less than 1 %. The variation observed for the reference cartridges across two instruments was also found to be good — 2.3 % for reproducibility test. The instrument was tested with human blood and serum samples on two distinct LFIA tests; Glycated Hemoglobin (HbA1c) and Vitamin D. The tests using blood/serum samples with both LFIA kits demonstrated excellent correlation. The correlation between the value measured by standard lab reference instrument and ImageQuant ratio-metric calculated output was 0.97 and 0.95 for HbA1C and Vitamin D tests respectively. The ImageQuant Analyzer can be a good substitute over traditional bulky, expensive LFIA Analyzers overcoming the many challenges posed by the latter in POC applications.