This research employed a mixed-methods design to provide a comprehensive understanding of the unregulated handling of biological samples among postgraduate students in Iraq. The study combined descriptive quantitative analysis, conducted through an online questionnaire, with qualitative analysis, derived from semi-structured interviews. This mixed-methods approach allowed the study to combine quantitative evidence on the prevalence of practices with qualitative insights explaining the underlying structural and contextual factors influencing these behaviors.

Data were collected using both quantitative and qualitative instruments, as follows:

A non-probability sampling approach was utilized for both components of the study:

Quantitative Component: A convenience sample of postgraduate students was recruited from various medical and life sciences fields across several Iraqi universities. Proportional representation was not a requirement for this component.

Qualitative Component: Participants for the interviews were selected using a quasi-purposive sampling method, based on their direct relevance to the research topic and their willingness to share their experiences.

Different analytical approaches were applied to the quantitative and qualitative datasets:

Quantitative Data Analysis: Quantitative data were analyzed solely using descriptive statistics, specifically frequencies and percentages. Inferential statistical tests were not applied due to the imbalanced representation of universities within the sample, which could introduce bias into the conclusions.

Qualitative Data Analysis: Qualitative data, derived from the interview responses, were analyzed using thematic analysis. This approach facilitated the identification of recurring themes and key insights pertinent to the research objectives.

Participants were informed of the study’s purpose and assured full confidentiality. Participation was voluntary, with the right to withdraw at any point, and no personally identifiable information was collected or recorded. The study was reviewed and approved by the Research Ethics Committee at the Genetic Engineering and Biotechnology Institute for Postgraduate Studies / University of Baghdad.

The quantitative data collected from 172 postgraduate students across various Iraqi universities provides valuable insights into the challenges, practices, and perceptions surrounding the handling and exchange of biological samples. The findings are presented below according to key thematic areas of the study:

This section presents the findings from the qualitative phase of the study, which involved 25 semi-structured interviews with postgraduate students. These students were drawn from diverse biological and medical science disciplines across various Iraqi universities. The interviews aimed to comprehensively explore the realities of biological sample handling, including motivations and challenges, awareness of associated risks, and the current state of biosafety training. The data were analyzed using Thematic Analysis to identify recurring patterns and insights from participants' responses.

The quantitative results indicated that a substantial majority of participants (71.5% out of 172 students) faced difficulties in obtaining necessary biological samples, while 78.5% reported that time constraints and limited access to adequately equipped university laboratories hindered their research progress. These figures are deeply contextualized and elaborated by the qualitative analysis. Interviews revealed that "poor infrastructure in university labs and shortage of essential materials" was the most frequently cited reason (mentioned in 21 out of 25 interviews), directly compelling students to seek alternative solutions. A typical quote from a postgraduate student at the University of Baghdad encapsulates this reality: "We don't have the necessary materials, and the university labs are barely functioning for a few hours during official hours-if the equipment even works at all-so we have no choice but to go to commercial labs."

This resource deficit directly translates into reliance on "commercial laboratories and external offices to conduct experiments" (quantitatively acknowledged by 65.1% of students) and the transfer of samples to these external facilities (80.2% quantitatively). The absence of adequate infrastructure is not merely an academic impediment; it represents a critical biosafety vulnerability [5,12]. Once biological samples leave a controlled laboratory environment, they become susceptible to multiple risks, including contamination, loss, or unauthorized use [13]. The lack of established protocols for transferring these samples between institutions, as evidenced by these practices, compromises the chain of custody, potentially leading to inaccurate research outcomes and increasing the likelihood of exposure to hazardous biological agents outside formal oversight [14], This unregulated movement of samples also raises biosecurity concerns, as it bypasses institutional controls designed to prevent the misappropriation or misuse of sensitive biological materials [15,16].

According to quantitative data, 51.7% of students acknowledged sharing biological samples with their peers, and another 19.2% did so on occasion. This suggests that informal collaboration is a coping mechanism. This behavior is supported by qualitative data, as 17 out of 25 participants personally admitted to exchanging samples, while the remaining participants said they knew others who did so. Statements like "We take samples from colleagues who already completed the practical part, because we don't have time to start from scratch" demonstrate how students are compelled to find these easy fixes due to time constraints and a lack of available samples.

While seemingly innocuous from the students' perspective, this practice poses significant biosafety and biosecurity risks. Informal exchange means a complete absence of traceability records, making it difficult to pinpoint the sample's origin in cases of contamination or misuse [17,18]. It also elevates the risk of pathogen transmission among individuals if stringent safety procedures (e.g., proper personal protective equipment use, safe waste disposal) are not followed [19,20]. From a biosecurity standpoint, this signifies a loss of control over potential biological agents, which could lead to undeclared laboratory incidents or even the unintentional release of pathogens into the community, thereby threatening public health [19,21].

The discrepancy between high-risk awareness and ongoing participation in risky behaviors is a startling paradox in this study. 91.3% of students acknowledged, quantitatively, that sample transfer would jeopardize sample integrity and result accuracy, while 82% said sample exchange involved "high risk." However, 60.5% of respondents still engaged in these procedures despite expressing concern about possible sample loss or leakage.

Qualitative findings elucidate this cognitive and behavioral dissonance. While 16 participants acknowledged the biological risks, they perceived them as an "unavoidable reality." A student from the University of Karbala vividly expressed this dilemma: "I know it’s wrong, but I have no choice, and time is running out." This highlights that awareness alone is insufficient to alter behaviors if viable alternatives are not available. In terms of biosafety, this means students' knowledge of risks does not translate into safe practices due to academic and institutional pressures, creating a dangerous gap between awareness and the actual implementation of biosafety measures [22]. This significantly increases the likelihood of serious biological incidents, given inadequate training and protocols [21,23].

Although 70.9% of students reported receiving some form of practical instruction, qualitative results revealed the insufficient nature of this training. Fifteen interviews indicated a lack of clear training programs, with existing training described as "purely theoretical, outdated (from undergraduate years), or non-specialized." One participant elaborated: "The training was just a lecture in undergrad, with no practical component. We never learned how to handle dangerous samples properly."

This issue is compounded by the scarcity of clear written protocols for biological sample handling, confirmed by only 29.1% of students. These gaps in training and protocols pose a substantial biosafety and biosecurity risk [11,24]. The absence of specialized practical training means students may lack fundamental skills for safe sample handling, increasing the risk of exposure to pathogens, cross-contamination, and infection spread [4,25]. Furthermore, the lack of standardized protocols fosters disorganization, makes sample tracking difficult, and creates an environment conducive to biological incidents and the potential misuse of biological materials [26,27]. The strong support (69.8%) for implementing a mandatory training program underscores students' recognition of this critical gap and the urgent need for institutional intervention.