Aim The aim of this study was to assess the psychometric properties of tools developed for the purpose of assessing infants with bronchiolitis.

Background Bronchiolitis is the leading cause of hospitalization in infants under the age of 1 year. Several bronchiolitis assessment tools have been developed primarily for use in randomized control trials of medical treatments for infants with bronchiolitis, however, the reliability and validity of many of these tools is not well reported.

Design Systematic review.

Data sources CINAHL, MEDLINE, EMBASE and PubMed electronic databases were searched between January 1960–December 2015 using the key words ‘bronchiolitis’ and ‘assessment’ or ‘screen’ or ‘tool’ or ‘scale’ or ‘score’.

Review methods A systematic review of the psychometric properties of bronchiolitis assessment tools was undertaken using the COSMIN checklist.

Results Fourteen studies meeting the inclusion criteria were reviewed and the methodological quality of the studies and reported psychometric properties of 11 instruments were assessed. Overall, the reliability and validity of bronchiolitis assessment tools was poorly established. Although several studies reported that their tools had good inter-rater reliability, the methodological quality of these studies was generally poor. Only one study underwent psychometric testing that was assessed as being of excellent quality. The Respiratory Distress Assessment Index was deemed to have undergone the most rigorous psychometric testing but had poor to moderate construct validity and considerable test–retest error.

Conclusion Current bronchiolitis assessment tools lack clearly established reliability and validity and may not be sensitive to clinically meaningful outcomes for patients.