Fork test: A new simple and reliable consistency measurement for the dysphagia diet.

The objective of this study was to validate fork test which is a simple tool to assess the consistency of food. The consistencies of 27 water and thickener mixtures were measured with a viscometer. These measures were then compared to those obtained with fork test to evaluate the validity of fork test. The inter-observer and intra-observer reliabilities of the fork test were assessed with an intra-class correlation coefficient. The viscometer was used to obtain reference values for three categories (0-300 cP, 300-10,000 cP, and >10,000 cP) in order to categorize water and thickener mixtures into grade 1, grade 2, or grade 3 according to the results of fork test. Our results revealed that the fork test showed excellent validity (r = -0.889, p < 0.05), intra-observer reliability, and inter-observer reliability. Therefore, fork test may be used as a practical tool to assess food consistency.