Salt iodization programs have been successful in reducing iodine deficiency, but to ensure program sustainability and appropriate monitoring of salt iodine levels, simple methods to quantitatively assess whether salt is adequately iodized are required. Thus, we validated the several quantitative rapid test kits (quantRTK) in a comparative manner for both their laboratory performance, reliability and ease of use in field settings.
Laboratory performance parameters were conducted on 5 quantRTK (iCheck, ID-ERTK, I-Reader, saltPAD, WYD) available at the time of the study (2015): linearity, detection and quantification limit, intra- and inter-assay imprecision. Further, we assessed inter-operator imprecision using salt of different quality along with the comparison of 59 salt samples from across the globe; measurements were made both in a laboratory and a field setting by technicians and non-technicians. Results from the quantRTK were compared against iodometric titration for validity. An âease-of-use’ rating system was developed to identify the most suitable quantRTK for a given task.
Most of the devices showed acceptable laboratory performance, but for some of them, use by non-technicians revealed poorer performance when using routine procedures. Of the quantRTK tested, the iCheck and I-Reader showed most consistent performance and ease of use. A newly developed paper-based method (saltPAD) holds promise if further developed.
User- and field-friendly devices are now available and the most appropriate quantRTK can be selected depending on the number of samples and the budget available. The availability and usefulness of such devices will render quantitative salt measurements easier.