RESUMEN
OBJECTIVE: To validate the defining characteristics of the nursing diagnosis "labile emotional control" in traumatic brain injury (TBI) outpatients. DESIGN: This was a descriptive, cross-sectional, quantitative study. METHODS: Thirty-one Brazilian nurses who were experts in the area of TBI answered a semistructured questionnaire on the diagnosis "labile emotional control" based on NANDA-International (NANDA-I) Taxonomy II (2015-2017) using a Likert-type scale to rate the 13 defining characteristics. Based on Fehring's model, the weighted average of ≥80 was used to define the main characteristic and the mean of ≥0.50 was considered for total content validation. RESULTS: Out of the 13 defining characteristics of the nursing diagnosis studied, "leaving a social situation" (0.80) and "expression of emotions inconsistent with the triggering factor" (0.81) were classified as principal characteristics, while the 11 others were classified as secondary characteristics. The diagnosis "labile emotional control" obtained a total score of 0.69, which was considered valid according to NANDA-I Taxonomy II. CONCLUSIONS: Because this is a new diagnosis with subjective characteristics, there is a need to train nurses to recognize the defining characteristics for the diagnosis. CLINICAL RELEVANCE: The validation of this diagnosis helps nurses understand and identify the subjective characteristics of the emotional impressions expressed by patients with TBI. These defining characteristics will help improve TBI nurses' clinical practice.