Fluorogenic hand-held immunoassay for the identification of ricin: rapid analyte measurement platform

Rapid analyte measurement platform (RAMPtrade mark) fluorogenic hand-held immunoassays (HHAs) were evaluated for inclusivity/sensitivity, exclusivity/specificity, sample matrix effects, ruggedness/stability, and reproducibility in detection of ricin (RCA(60)), a potential biological threat agent. The limit of detection of HHAs for RCA(60) was 14 ng/mL or approximately 140 pg/test. HHAs were inclusive in detection of ricin RCA(60), RCA(120), ricin A chain, and ricin B chain and exclusive in discrimination of RCA(60) from other toxins. None of the sample matrices tested affected assay performance. RAMPtrade mark ratios were tolerant of increases in sample volume, however, a decrease in sample volume of 25% resulted in significantly increased readings. RAMPtrade mark readings were highly reproducible lot-to-lot, cartridge-to-cartridge, day-to-day, and reader-to-reader.