Evaluation of rapid test kits for quantification of HT-2 and T-2 toxins in naturally contaminated oats

The aim of this study was to evaluate the performance and usefulness of three rapid test kits for analysis of HT-2 and T-2 toxins (HT-2 and T-2), two of the most potent trichothecenes commonly found in European oats. Concentrations of these two toxins combined (HT-2+T-2) were analysed in naturally contaminated oat samples (n=68) using the following test kits: Ridascreen (R) FAST T-2 Toxin ('Fast ELISA'), DRAFT Ridascreen (R) HT-2/T-2 ('Standard ELISA; not commercially available), and the lateral flow device ROSA (R) HT-2-T-2 ('Rosa LFD'). Mycotoxin analysis by LC-MS/MS was used as a reference method. Rosa LFD offered the best reliability, achieving detection that was stable across toxin levels, whereas detection by both ELISA kits differed significantly among toxin levels (P<0.01). The kits were also evaluated regarding agreement with the reference method (measured as Cohen's kappa) at a HT-2+T-2 concentration of 1000 mu g/kg in naturally contaminated oats. Agreement was greatest for Rosa LFD (89.2%), intermediate for Standard ELISA (66.8%), and lowest for Fast ELISA (62.2%). Rosa LFD showed cross-reaction of 100% with both T-2 and HT-2. For the ELISA kits, cross-reactions were 100% with T-2 but below 100% with HT-2. Therefore, to estimate the sum of HT-2 and T-2 in an oat sample, it was necessary to re-calculate the data from both ELISA kits according to the known cross-reaction of each kit with HT-2 and the concentration ratio of HT-2 to T-2 in Norwegian oats. Rosa LED had the highest correlation with LC-MS/MS (R-2=0.94), and the corresponding R-2 values for Fast and Standard ELISA were 0.61 and 0.83, respectively. Rosa LFD was well suited for on-site detection. Standard ELISA allows simultaneous testing of several samples that are useful for centralised laboratories.