It is unknown if the DSM-oriented (DSM) scales of the Youth Self-Report (YSR) are useful to determine what kind of narrowly-focused psychiatric assessment is needed, and how well these scales serve as a triage tool in real-world forensic settings. To address this knowledge gap, the YSR and diagnostic interviews were administered to 405 detained boys as part of a clinical protocol. Continuous DSM scale scores (e.g., Conduct Problems) were moderately to highly accurate in predicting their corresponding disorder (e.g., conduct disorder), whereas dichotomized DSM scale scores were not. To test the DSM scales' usefulness for triage purposes, the sensitivity and specificity of being in the borderline range of one or more DSM scales were calculated. Almost all boys who did not have a disorder were in the normal range of at least one DSM scale (high specificity). However, many boys with a disorder would have been missed if such a decision rule was used for triage purposes (low sensitivity). In conclusion, their relations with the corresponding disorders support the construct validity of the DSM scales in an applied forensic setting. Nevertheless, the findings also warrant against the use of these scales for planning further narrowly-focused assessment or for triage purposes.