Validation of the IDDSI funnel for liquid flow testing

In 2017, the International Dysphagia Diet Standardisation Initiative (IDDSI) introduced the IDDSI flow test which enables patients, clinicians, caregivers, food service professionals and researchers to classify liquid thickness into five levels based on the volume of liquid remaining in a standard 10 mL slip tip syringe after 10 s of flow under gravity. Within a few months of publishing the IDDSI flow test instructions, several barriers emerged: (1) the preferred model of syringe (BD 303134) was not equally accessible around the world, causing some users to perform flow tests with alternate models of syringe; (2) differences in syringe geometry across models led to variations in IDDSI flow test results; and (3) the need to use a second syringe for sample loading added complexity and cost to end users. To address these barriers, IDDSI designed the IDDSI funnel, a novel device, which combines the geometry of the BD 303134 syringe with a kitchen funnel to facilitate easy loading of liquid samples without need for a second syringe. In this report, we compare the IDDSI flow test results across two devices: syringe BD 303134 and IDDSI funnel. IDDSI level classifications were in complete agreement with the syringe reference test results in 67/73 (92%) of the test fluids and temperature conditions with mean difference of residual liquid across devices of 0.2 (2% full scale). These results demonstrate excellent correspondence between the two devices.