Summary of results from the ‘method’ validation of the different quantRTK’s.

a LoD, limit of detection; LoQ, limit of quantification; for the description of the calculations, refer to the description in the method section;b three iodine levels were used (15.0, 29.6, 59.1 mg/kg) and the three CV’s are given in the order of increasing iodine concentration;c Recovery A was calculated from the linearity assessment, and results are presented as mean recovery ± SD; Recovery B was calculated from the inter-operator precision exercise and comprises the observed/expected values from the samples with approximate KIO3 concentrations of 15, 20, 30, 45, 60, and 90 mg/kg; results are shown with % SD.d the device gives results in mg/L and anything above 13mg/L is indicated as 'above measuring range'; assuming 1:5 dilution (factor 5.45), this corresponds to 65 mg/kg;e The device has set working ranges from 15–50 mg/kg and thus, LoD and LoQ could not be assessed; further, for intra- and inter-assay imprecision and recovery, the low level of salt (15.0 mg/kg) could not be assessed; the high level yielded results, because the device gave consistently lower readings; n/d thus, means not determined;f For the saltPAD, three types of interpretation of the results on the cards were done: interpretation by the operator, by an expert reader (a person from the device developer) and an image analysis software; for the device performance, the expert reader’s results only were used.Summary of results from the ‘method’ validation of the different quantRTK’s.