Psychometric properties and concurrent validity of the Transgender Congruence Scale (TCS) in the Swedish setting

The Transgender Congruence Scale (TCS) is a non-binary tool used in Sweden for gender dysphoria (GD) assessment; however, its Swedish version has not been validated. To investigate the psychometric properties of the TCS, its capacity to distinguish individuals with GD and its concurrent validity compared to other scales. Patients with GD (n = 135) and controls (n = 443) filled in a questionnaire containing sociodemographic questions, the TCS, the Utrecht Gender Dysphoria Scale (UGDS), and the Gender Identity/Gender Dysphoria Questionnaire for Adolescents and Adults (GIDYQ-AA). TCS had good discriminatory validity and internal consistency. Patients with GD, stratified by birth-assigned sex, had lower TCS scores compared to controls. Confirmatory factor analysis (CFA) supported the two-factor model of the TCS. Multiple-group CFA suggested measurement invariance between birth-assigned sexes and configural invariance between patients with GD and controls. Area under the ROC curve for birth-assigned males was 0.991 and for females 0.994. A TCS mean value of three provided sensitivity 94.3% and 95.1% as well as specificity 98.6% and 98% for aM and aF, respectively. The TCS was significantly correlated to UGDS and GIDYQ-AA. The TCS may be a valuable tool in the clinical assessment of individuals with GD.