Practitioner perceptions of human factors contributing to DNA contamination risk in forensic practice: a cross-sectional survey

Abstract Background Modern forensic DNA methods can recover low-level, trace, and mixed profiles, increasing the importance of contamination control, background DNA, and secondary-transfer-aware interpretation. This cross-sectional online survey of 100 forensic practitioners, contextualised by a targeted narrative literature search, examined perceived human-factor risks, contamination-event experience, and prevention priorities. Responses were analysed descriptively, and each open-ended response was grouped according to its principal recommendation. Results Retained aggregate mean Likert ratings were 4.58 for workload, 4.51 for fatigue, 4.46 for time pressure, 4.42 for improper glove changes, 4.39 for personal protective equipment (PPE) non-compliance, 4.31 for interruptions and distractions, 4.25 for communication failures, and 4.20 for staffing shortages. Sixty-two of 100 respondents reported witnessing or being involved in a DNA contamination incident, and 81 of 100 reported observing a near-miss. Among the 62 respondents reporting contamination-event experience, workload was the most frequently identified primary contributor (29.0%), followed by PPE non-compliance (21.0%), communication failures (16.1%), improper glove changes (12.9%), time pressure (11.3%), laboratory layout or workspace constraints (6.5%), and other factors (3.2%). Open-ended responses ( n = 100) emphasised workload management (44%), training and competency (27%), communication and team coordination (16%), and quality culture and reporting (13%). Conclusions Practitioners perceived DNA contamination as a socio-technical quality issue shaped by interacting operational, behavioural, organisational, and environmental conditions. The author-developed, survey-informed Human-Factor DNA Contamination Framework is presented as a non-scored, non-predictive, and unvalidated conceptual aid for structured risk review and future empirical assessment.