Test-retest reliability of the Food Allergy Quality of Life Questionnaires (FAQLQ) for children, adolescents and adults

Abstract

Objective: The self-administered Food Allergy Quality of Life Questionnaire-Child Form (FAQLQ-CF), -Teenager Form (FAQLQ-TF) and -Adult Form (FAQLQ-AF) were recently developed within EuroPrevall, a multi-centred study of food allergy in Europe. The primary aim of this study was to evaluate the test-retest reliability of the FAQLQ-CF, -TF and -AF. Methods: One hundred and one Dutch patients (31 children, 34 adolescents and 36 adults) completed the FAQLQ twice with a 10-14 day interval. The intraclass correlation coefficient (ICC), Lin's concordance correlation coefficient (CCC) and Bland-Altman plots were used to assess test-retest reliability. Results: Test-retest reliability was excellent with ICCs and CCCs above 0.907, 0.975 and 0.951 for the FAQLQ-CF, -TF and -AF, respectively. Bland-Altman plots showed that the mean differences of the test and re-test were all close to zero for the FAQLQs. Conclusions: The FAQLQs are reliable over a short time interval. The FAQLQs are not only excellent tools for group comparison studies, but also for monitoring individual patients.