Co‐Design of a Theory‐Informed, Multicomponent, Intervention for Diagnostic Stewardship in a Major‐Referral Emergency Department: A Qualitative Descriptive Study

ABSTRACT

Objective

Low‐value diagnostic tests harm patients. Stewardship of tests can improve patient safety. Co‐design and behavioural change theories can enhance the effectiveness of diagnostic stewardship interventions. This study aimed to co‐design a theory‐informed diagnostic stewardship intervention at a major‐referral emergency department in Queensland, Australia.

Methods

A qualitative study was conducted at Townsville University Hospital Emergency Department. The Theoretical Domains Framework underpinned intervention design. Emergency clinicians ordering pathology tests were eligible for inclusion. A purposive sample of consenting participants was recruited. Data were collected via workshops facilitated by the lead author. Conversations were audio recorded and digitally transcribed. Data were managed with NVivo. Data were analysed by inductive and deductive approaches to generate codes, categories and themes. Thematic saturation and optimal stakeholder engagement influenced the final sample size. Trustworthiness was ensured via reflexivity, audit trail, thick description and participant validation.

Results

Seven workshops were conducted with 35 emergency physicians (18 male, 17 female) with a range of specialist experience (1–31 years). Urine culture was the diagnostic test of choice. Culture, complexity, and efficiency were identified as the major drivers of low‐value urine cultures. Education, nudge, clinical champions, and audit/feedback were selected as intervention components. Credibility of change and workflow inefficiency were perceived as intervention challenges.

Conclusion

Stakeholder engagement has enhanced perceived acceptability of this co‐designed intervention for urine culture diagnostic stewardship. Behavioural change theories strengthen co‐designed interventions by addressing context‐specific drivers of low‐value tests. Co‐design and behavioural change theories can inform bespoke interventions to nurture a culture of diagnostic stewardship in emergency medicine practice.

1. Introduction

Low‐value diagnostic tests are unscientific, ineffective, inefficient, inequitable and increase the risk of patient harm [1, 2] At least one third of some diagnostic tests have been shown to be low‐value in multiple emergency department (ED) settings, including Australia [3, 4] Diagnostic stewardship—appropriate test ordering, processing and reporting—enables clinicians to avoid low‐value tests by ordering the right test for the right patient at the right time, thus improving patient care, safety and outcomes [5].

Interventions to promote diagnostic stewardship in emergency medicine practice have included the following components: stakeholder engagement, education, training, nudge, clinical champions, incentive and audit/feedback [6]. Multicomponent interventions have been reported to be more effective than interventions with a single component [6]. However, multicomponent interventions have not been found to be uniformly effective indicating that effectiveness is determined by fidelity that is, the process of design and implementation [6].

Behavioural change theories, such as the Theoretical Domains Framework (TDF), [7] have been reported to increase effectiveness [8, 9] of interventions by modifying clinician behaviours that contribute to low‐value tests. TDF‐informed interventions have successfully changed emergency clinician behaviour, improving cervical spine Computed Tomography stewardship [8] opioid stewardship [10] guideline‐concordant infant bronchiolitis care [9] nursing care quality [11] and suicide prevention [12] However, theory application alone does not guarantee intervention effectiveness, as evidenced by the failure of theory‐informed ED interventions to improve cranial Computed Tomography stewardship [13] and triage, treatment and transfer of acute stroke patients [14] This inconsistency suggests that behaviour change theory may be necessary but not sufficient; effectiveness may also depend on how well interventions are tailored to local context and developed with the involvement of clinicians/end users, rather than applied top‐down.

Co‐design, a third feature that enhances intervention effectiveness, is a process where research participants are engaged as partners in intervention design, implementation and evaluation [15]. This partnership ensures that the co‐designed intervention incorporates strategies to meet end‐user needs and challenges [16]. This collaborative process also allows identification and navigation of context‐specific drivers of low‐value diagnostic tests [17]. The TDF enables behavioural framing of the identified drivers [17] followed by matching to the intervention components best equipped to navigate the drivers [6].

Drivers of low‐value diagnostic tests vary from concern about consequences (fear of litigation due to missed diagnoses) for imaging in minor head injury [18] to cultural influences (perceived patient expectations) for imaging in low back pain [19] Interventions should therefore be calibrated to individual diagnostic tests to effectively address the underlying drivers [6] Co‐design can inform the choice of a diagnostic test by enhancing buy‐in from key stakeholders through evidence‐informed deliberations about test volume, value and prioritisation [20, 21].

Prior ED studies have co‐designed interventions to improve patient experience [22], paediatric mental health discharge communication [23], take own leave rates in First Nations patients [24], suicide safety planning [25], person‐centred triage [26], and care of dementia patients experiencing access block [27]. Emergency Medicine literature to date has also evaluated the impact of behavioural change theories on interventions for diagnostic stewardship of Computed Tomography in adults with neck trauma [28] and chest radiographs in infant bronchiolitis [29]. However, there is an absence of published ED studies exploring the impact of co‐design on diagnostic stewardship interventions informed by behavioural change theories. This study aims to address this specific knowledge gap by describing the co‐design of a theory‐informed, multi‐component intervention for diagnostic stewardship at a major‐referral Australian ED.

2. Methods

2.1. Design

This study used a qualitative design in which workshops served as the primary data collection method. Workshops were chosen as they enable participants with shared experiences to engage in an unrestricted, collaborative, inclusive, creative process to achieve a pre‐defined objective [30].

2.2. Location

The study was conducted at Townsville University Hospital ED, a major‐referral, mixed ED in Queensland, Australia with an annual patient census of 96,855 in 2025. (Personal communication by e‐mail from ED Business Practice Improvement Officer). Townsville University Hospital ED has access to round‐the‐clock laboratory service. Laboratory tests are ordered by doctors, physician assistants and nurse practitioners.

2.3. Theoretical Framework

The intervention design was grounded in the TDF [31] an implementation science framework derived from synthesis of 33 behavioural change theories and 128 theoretical constructs. The TDF was the theory of choice for this study due to its reported effectiveness in changing a diverse range of emergency clinician behaviours including stewardship of diagnostic tests [8, 9] The TDF was used in this study to interpret the identified drivers and inform intervention components. The TDF was not used for deductive coding.

2.4. Intervention Co‐Design

Co‐design was informed by prior research about prevalence [32] and drivers [6, 17] of low‐value diagnostic tests as well as the effectiveness of interventions to de‐implement low‐value diagnostic tests in emergency medicine practice [6] Co‐design was guided by the method described by Curran et al. [33] and was conducted in two phases.

2.5. Objectives of Co‐Design Workshops

The objectives of the co‐design workshops were to sequentially choose one target diagnostic test, concur on indications for the chosen test, identify drivers of low‐value target test orders and design an intervention with components that address identified drivers.

2.6. Phase 1: Design of Prototype Intervention

Emergency clinicians who ordered laboratory tests were eligible. Potential participants were invited to participate via an in‐person meeting and through an e‐mail explaining the purpose of the workshops. A purposive sample of consenting participants was recruited. There was no overlap of participants between workshops, with each participant taking part in one workshop only.

Prior to the workshops, recruited participants were e‐mailed a primer document (Supplementary Appendix S1) that succinctly summarised the evidence for diagnostic stewardship [5], prevalence of candidate low‐value diagnostic tests at Townsville University Hospital ED [32], and evidence‐based recommendations for diagnostic stewardship of the candidate tests [34, 35, 36]. Participants were presented with the following elements which were predefined in the primer document before the workshop: candidate diagnostic tests, evidence‐based appropriate indications for candidate diagnostic tests, potential drivers of low‐value candidate tests, [17] potential intervention components to overcome the drivers [6] and optimal driver‐component pairing for maximal intervention effectiveness [6]. Coagulation studies, blood cultures, and urine cultures were included as options as they had the highest proportion of low‐value tests at the study site [32]. Culture, complexity, consequences, abilities, resources and efficiency were discussed as drivers of low‐value tests [17]. Stakeholder engagement, nudge, clinical decision support, clinical champions, education, training, and audit/feedback were deliberated as intervention components [6]. Nudge was defined as the process of influencing clinician behaviour by modifying physical or social environment without actively restricting options [6].

Workshops were conducted in a quiet ED meeting room at participants' convenience, facilitated by the lead author and guided by the primer document. The workshops lasted 30–90 min, were audio recorded and transcribed using an artificial intelligence software (otter ai).

The workshops followed a structured format that commenced with a preamble where the lead author stated the purpose, defined diagnostic stewardship, clarified questions/concerns and ensured informed consent. This was followed by a discussion where participants sequentially debated the choice of the diagnostic test, appropriate clinical indications for the chosen test, the drivers for inappropriate ordering of that test and the components best suited to navigate the drivers. The depth and duration of deliberations were determined by the participants' comprehension and clarity about each of the above elements of the intervention. When clarification was needed, deliberations extended to ensure shared understanding of all elements. This reflected principles of co‐design and the need for iterative meaning‐making when designing complex interventions. Final decisions were made by participant consensus. The following elements of the intervention were generated by the participants through the co‐design process: the final target test, the final list of appropriate indications for the target test, the specific drivers of low‐value orders of the target test and the specific intervention components to address the identified drivers.

The intervention was refined in each workshop whilst being guided by acceptability, practicability, effectiveness, affordability, safety and equity (APEASE) criteria [37]. The final number of workshops was determined by thematic saturation and the need for consensus through optimal stakeholder engagement. Senior medical officers participated in Phase 1. Other clinicians (junior medical officers, physician assistants, nurse practitioners) who order laboratory tests at the study sites were not involved in the initial co‐design of the intervention.

2.7. Phase 2: Refinement of Prototype Intervention

The workshop deliberations were synthesised into a draft document which was e‐mailed to participants to seek general feedback, address residual concerns and secure consensus about the intervention. Participant continuity was ensured between the two phases of intervention design by seeking feedback from all participants in Phase 1. Phase 2 resulted in no changes to the intervention.

As part of the change management process, internal and external stakeholders were engaged [16] in a general discussion about the intervention after completion of Phase 2. Senior ED nursing and allied health clinicians were supportive of the intervention; however, they viewed ordering laboratory tests as a medical responsibility and beyond their scope of practice. Physician assistants and nurse practitioners backed the intervention but had no further input. Prior research at the study site showed that senior medical clinician leadership/role‐modelling and evidence‐based guidelines were critical to support junior medical clinicians in diagnostic stewardship [17] In another qualitative study, patients who had received care at TUH‐ED expected effective communication tailored to individual patient values/preferences/life experiences and trusted emergency clinicians to order appropriate, symptom‐based laboratory tests [38] The leadership of departments of infectious diseases, pathology, and microbiology endorsed the co‐designed intervention. Based on all of the above, other stakeholders did not participate in co‐design. The consultations did not yield additional data or alter the intervention.

2.8. Data Management and Analysis

Data were imported into NVivo for management and analysis. The unit of analysis was the organisation, that is, Emergency Department that is collectively codesigning the intervention. Analysis followed a hybrid deductive‐inductive approach to balance structured analysis with emergent findings [39]. A coding framework was developed a priori, using the four sequential objectives of the co‐design workshops (choice of target test, concurrence on indications, identification of drivers, selection of intervention components). These a priori objectives enabled combination of data across workshops and analysis at the departmental (rather than individual participant) level. Within each a priori objective, data were analysed inductively to identify codes, which were grouped into categories and synthesised into emergent themes. The lead author coded all the workshop transcripts. Two co‐authors (RE, KC) regularly peer‐reviewed the codes. Disagreements during data analysis were resolved by discussion and consensus. Coding and themes development continued until saturation was achieved. Saturation was deemed to have been achieved when no new codes, categories or themes emerged from further review of data [40].

2.9. Trustworthiness

Trustworthiness of the process was ensured using reflexivity, audit trail, thick description and participant validation [41]. Reflexivity ensured that the lead author‐ a male, middle‐aged, emergency physician with 9 years of specialist experience‐ was cognisant of personal biases, due to prior research and the focus on de‐implementing low‐value tests, during data analysis. Audit trail involved maintaining a detailed record of identification and evolution of codes, code categories and emergent themes and resulted in a transparent account of transformation of data into findings. Periodic peer review of initial codes by co‐authors through in‐depth discussion of data analysis with the lead author contributed to trustworthiness. Thick description—rich, detailed explanation of participants' views, circumstances and motives—enabled the findings to be grounded in the data. Participant validation, review and approval of the final manuscript by participants, ensured that the findings accurately reflected participant views. Validation did not result in any changes to the intervention or the manuscript.

2.10. Ethics and Reporting

Townsville Hospital and Health Service Human Research Ethics Committee approved this study (AM/2024/QTHS/89509). The reporting aligns with consolidated criteria for reporting qualitative research (COREQ) guidelines [42](Supplementary Appendix S2).

3. Results

Seven workshops with 35 participants were conducted between April 2025 and September 2025. All participants were Emergency Physicians with specialist experience ranging from 1 to 31 years. Participant characteristics are presented in Table 1.

TABLE 1.

Characteristics of participants in workshops to co‐design a diagnostic stewardship intervention at Townsville University Hospital Emergency Department.

	Participant characteristics
	Gender		Specialist experience median (Interquartile range) years
	Male	Female
Workshop 1	1	5	11.5 (8–12)
Workshop 2	2	5	10 (6.5–12.5)
Workshop 3	4	0	9 (6–16)
Workshop 4	6	1	9 (7.8–13.3)
Workshop 5	1	2	8 (6–12)
Workshop 6	2	3	10 (7.8–10.8)
Workshop 7	2	1	14 (9–15.5)

The results are presented under the four sequential co‐design workshop objectives used a priori as the deductive analytic structure (target test, indications, drivers, and intervention) and two emergent themes (diagnostic stewardship, intervention challenges).

3.1. Choice of Target Test

Urine cultures were chosen as the target for intervention. This choice was influenced by high prevalence, patient harm (prolonged wait, unnecessary antimicrobials), and clinician workload of low‐value urine cultures as well as the potential impact of an intervention to steward urine cultures. Table 2 illustrates the reasons for participants' choice.

TABLE 2.

Reasons for participants' choice of test in workshops to co‐design a diagnostic stewardship intervention at Townsville University Hospital Emergency Department.

Reasons for choice	Participant quotes
Prevalence	“Urines are getting sent on huge amounts of people that don't need it, whereas the blood cultures tend to get sent on at least febrile people.” (P2)
Patient harm	“…potential harm for patients of having to wait around… for longer, having to have invasive… specimens… being commenced on antibiotics unnecessarily, based on the… spurious result of a urine, is much higher than the blood cultures” (P8)
Clinician workload	“… it would have to be urine…cultures that you would eliminate, because coags … is a pointless test if you've done it, but it has less detriment on…future workload.” (P7)
Intervention impact	“I think we have a more powerful direct influence on urine cultures,” (P1) “…something that's measurable and simple” (P24)

Abbreviation: P, participant.

3.2. Concurrence on Indications

Dysuria, haematuria, urinary frequency/retention/incontinence, lower abdominal/flank pain/tenderness, fever/sepsis/delirium of unknown cause and ED senior medical officer discretion were agreed upon as indications for urine cultures in adult (≥ 18 years), non‐pregnant and immunocompetent patients.

3.3. Identification of Drivers

Culture of ordering routine tests, complexity of decision‐making during cognitive overload and need for efficiency amidst ED overcrowding were perceived as the major drivers of low‐value urine cultures. The influence of clinician abilities, consequences and resources was felt to be minimal, although some participants disagreed. Illustrative participant quotes are presented in Table 3.

TABLE 3.

Drivers of low‐value urine cultures in workshops to co‐design a diagnostic stewardship intervention at Townsville University Hospital Emergency Department.

Drivers	Participant quotes
Culture	“Everybody comes in the department gets a urine…Oh the urines got a trace of leucocytes…send it off.” (P23) “… it becomes a habit when you do your presets. And so abdominal pain …you've got a urine…MCS in there, which you need to… adjust…” (P33)
Complexity	“…it's just easier to get it done, because it's, you know, there's other stuff going on, the cognitive load.” (P3) “You don't know what's going on out there. It's like, 45 people and you're like, yeah, just scan that one, send that urine.” (P22)
Efficiency	“… the easiest thing to do is just to order a few tests and then, … rationalise…were they needed in the first place? But if we had all the time in the world, you know you'd go and see all of these patients and make a decision straight away,” (P17) “…people just ordering them on every abdo pain from triage… shouldn't…order… until we have either a history, an exam suggestive of or a dipstick that fits with, right?” (P24)
Resources	“For me… easy availability is not the reason” (P27) “…lack of available staff and space to put people into the investigation, then…back in the waiting room rather than getting a proper look at first” (P34)
Consequences	“… I personally am not that concerned about being sued if I don't send off urine.” (P31) “…fear of adverse outcome is a big driver of all of this…because people feel we have to do absolutely everything. It's true like we over investigate these days massively. That's all of us” (P34)
Abilities	“I think you can talk till you are blue in the face in terms of orientation and education, but it's what you do on the shop floor.” (P25) “…because people ordering the tests are junior…don't have the same level of experience that we do.” (P14)

Abbreviation: P, participant.

3.4. Design of Intervention

Deliberations about the intervention focussed on components and timepoints.

Nudge, clinical champions, audit/feedback, and education were the intervention components. Table 4 demonstrates the TDF domains that link the identified drivers and intervention components.

TABLE 4.

The Theoretical Domains Framework‐informed driver‐component pairing of low‐value urine cultures in workshops to co‐design a diagnostic stewardship intervention at Townsville University Hospital Emergency Department.

Identified drivers	Relevant domain of the TDF	Chosen intervention components
Culture	Social influences Behavioural regulation	Clinical champions Audit and feedback
Complexity, efficiency	Environmental context and resources	Nudge
Abilities	Knowledge	Education

Abbreviation: TDF, theoretical domains framework.

The preferred nudge timepoint was when urine cultures were ordered by prompting clinicians to enter an appropriate indication in the mandatory ‘reason for order’ free text box in the electronic medical record. Urine collection and urinalysis were considered as timepoints but excluded as interventions at these stages were felt to be inefficient. The laboratory processing phase (no test if no indication coupled with a phone call from lab) was proposed; however, it did not gain traction due to concerns about potential patient harm resulting from inadvertent absence/inaccuracy of indications. Consultation with leadership of infectious diseases, pathology and microbiology departments also revealed that phone calls were not feasible. A second proposed lab timepoint (no culture if no pyuria on microscopy) was also deemed impractical by the laboratory team due to workflow inefficiency. A drop‐down menu of appropriate indications for urine culture orders was accepted as ideal but impractical and unaffordable due to the need for a statewide change involving stakeholders with competing priorities. Tables 5 and 6 illustrate participant quotes about intervention components and nudge timepoints respectively.

TABLE 5.

Intervention components in workshops to co‐design urine culture diagnostic stewardship intervention at Townsville University Hospital Emergency Department.

Intervention components	Participant quotes
Nudge	“Which one of those…reasons (appropriate indications) are you doing urine for…and if not, talk to your boss.”? (P19)
Clinical champions	“…that's why, I think… that social environment, of talking about why we are doing tests… it's beneficial” (P10) “I think the barrier shouldn't have to be…physical or technological. The barrier should be like us as a group…the entire consultant group to drive it hard.”(P22)
Audit and feedback	“I think that's gonna be the best way to help enforce it. A, …see if the message is getting through, and B, help us come back and say, ‘Hey guys, remember that thing we talked about? Still not doing it’.” (P33) “Group feedback, everyone goes, it's not me, and just switches off. They never take it personally. I think it needs to be individualised. But I think if you realise that you're the serious outlier it might be more.” (P28)
Education	“If frontline staff have easy access to the information that they need… that's readily available to support them.” (P1) “…having them primed so that I know the one‐on‐one probably has the most evidence, but small groups and not a didactic but more like a conversational format, … creating a context in their brains, like they'd be familiar with antimicrobial stewardship. So now we just create that for diagnostic stewardship…” (P24)

Abbreviation: P, participant.

TABLE 6.

Nudge timepoints in workshops to co‐design urine culture diagnostic stewardship intervention at Townsville University Hospital Emergency Department.

Nudge timepoints		Participant quotes
ED (ordering phase)	Collect specimen	“I don't think you can take away the urine jars. That's really annoying.” (P7) “If urine's not indicated, don't give them a container in the first place.” (P2) “I would…rather have a urine for every single patient… than limit who they're collecting the urine on. Then it's up to the people at the next level to decide what we do with it.” (P12)
	Perform urinalysis	“I wouldn't be asking the nurses to decide whether to dip or not. I'd let them continue their dipping… then we decide who to culture” (P31) “So, I don't think we should…create a barrier to doing a urine dip.” (P9) “…I still think we should encourage the nurses to do what they're doing, which is early catching and maybe dipping” (P28)
	Place EMR order	“…EMR…where you order the test, and there has to be some kind of mandatory drop‐down bar that you fill in…the reason…” (P14) “little checklist … stuck to the side of the computers… to steward the junior doctors…requesting urine MCS” (P8)
Lab (processing phase)	No test if no documented indications	“I think that's dangerous, because… somebody could have really bad urine sepsis, but somebody just didn't put in the details right. So, I think that potentially that could result in bad patient outcomes” (P28) “micro…we're going to stop sending you as much urine. So, all you've got to do is just call the consultant on the fast track or floor if you get sent a urine and it doesn't have one of these five indications that we've decided” (P14)
	Microscopy without culture	“…microscopy, and… culture. Those are actually two tests. There's a lot of microscopy that's normal that then still gets cultured. Why?” (P15)

Abbreviations: ED, emergency department; EMR, electronic medical record; Lab, pathology laboratory; P, participant.

3.5. Diagnostic Stewardship

Stewardship was viewed as an essential part of patient care and acknowledged as not being the current standard of care. Illustrative participant quotes about diagnostic stewardship are presented below.

I feel it's vitally important. (P8)

I don't think based on my interactions…, that everybody values it. (P10)

Emergency clinicians were held accountable for ensuring appropriateness of tests.

I think we've all got different versions of common sense as well, depending on our influences throughout our own training experiences… but ultimately, it's accountability…for what you're doing (P9).

An incremental approach towards a stewardship culture was thought to be pragmatic.

…I think it's easier to pick tests where you can make an argument…that we're wasting a lot of resources… And then it gets people thinking…, ‘what else am I doing that I don't need to do’? (P1).

3.6. Intervention Challenges

Credibility of change, change management, missed diagnoses, workflow inefficiency and intervention ineffectiveness were the key challenges that concerned participants. Illustrative participant quotes are presented in Supplementary Appendix S3.

4. Discussion

This qualitative study has resulted in a co‐designed, theory‐informed, multicomponent intervention for urine culture diagnostic stewardship. The following discussion expounds upon the impact of co‐design and behavioural change theories on the evolution of the intervention.

4.1. Co‐Design

The collaborative process of co‐design was critical to incorporate participant views and address concerns. The primer document raised participant awareness, clarified purpose, anchored discussions, and influenced decisions.

The choice of test was influenced by alignment of participants' prior clinical experience with the reported prevalence (47%) [32] of low‐value urine cultures at the study site. Interestingly, participants with disparate experiences remained unconvinced of the magnitude of the problem and the need for intervention despite the data. This finding of facts not changing minds has been noted by cognitive scientists who have reported that the human brain is primed to refute new information without evidence and biased to seek data compatible with existing beliefs when faced with contentious and complex issues [43]. This conflict was managed through an agreement to trial the intervention. The discretionary indication for urine cultures likely assuaged participant concerns about loss of autonomy. The fear of losing autonomy is a documented barrier to de‐implementation of low‐value care [44].

Participants felt that low‐value urine cultures were predominantly due to system‐level (efficiency, complexity, culture) rather than individual‐level (abilities, consequences) drivers. This finding was mirrored in a survey of 221 Dutch emergency clinicians by van Horrik et al. where efficiency and culture drove low‐value urine cultures [45]. This dominance of systemic drivers could be a manifestation of the documented effects of physical and social environment on human behaviour [46]. Efficiency and culture have also been noted as drivers of other low‐value diagnostic tests [17, 29, 47, 48], underlining their influence on emergency clinician test ordering behaviour.

The timepoint of intervention generated robust debate which was resolved in favour of ED ordering phase rather than laboratory processing phase. Interventions that focus on laboratory processing exclude emergency clinicians who are primarily responsible for ordering urine cultures. This deferment of decision‐making responsibility propagates the prevailing culture of ordering ‘routine’ or ‘baseline’ tests [17, 49] and represents a lost opportunity to nurture a culture of diagnostic stewardship [5] in emergency medicine practice.

4.2. Behavioural Change Theories

The TDF domains helped conceptualisation of the identified drivers of low‐value urine cultures in behavioural terms. The workshops enabled our participants to understand that efficiency, complexity, and resources mapped to environmental context and resources domain, whereas culture aligned with the domains of social/professional role and identity, social influences, and behavioural regulation. This behavioural framework informed the choice of nudge to address efficiency, complexity, and resources, while culture was tackled with clinical champions and audit/feedback components. Clinician abilities and knowledge about appropriate indications were not perceived to influence low‐value urine cultures. However, participants felt that targeted education was essential to embed diagnostic stewardship in practice. Stakeholder engagement, which manages the three drivers addressed by nudge, was an implicit component of the intervention due to co‐design.

Our intervention is similar to a TDF‐informed, multicomponent intervention employed by Haskell et al. to improve evidence‐based hospital care in infant bronchiolitis [9]. ED studies of urine culture diagnostic stewardship interventions have not reported the use of behavioural change theories [50, 51, 52, 53, 54].

4.3. Strengths and Limitations

Involvement of emergency physicians as participants is a strength as engagement of senior leadership enables de‐implementation of low‐value emergency care [6]. Despite lingering concerns about intervention effectiveness and changing clinician behaviour, the workshops enabled a consensus through a proposed evaluation of the intervention. Intervention design at a single emergency department by emergency physicians alone limits transferability of findings. However, the elements of co‐design outlined in this report can inform the process of stakeholder engagement which appears important for development of context‐specific behavioural change interventions. Co‐design may indeed be a critical step in contextualisation of interventions to different healthcare settings as evidenced by the failure of an acute stroke care intervention to change emergency clinician behaviour [14] despite being successful in non‐ED setting [55]. Absence of other key stakeholders (patients, nursing, allied health, junior medical clinicians) in co‐design workshops is a limitation. The magnitude of impact of this absence on the final intervention is uncertain but mitigated to an extent by findings of prior research that included patients [38] and junior medical clinicians [17] as well as the consultation process with the nursing and allied health clinicians.

4.4. Implications for Practice, Policy, Research

The co‐designed intervention is being implemented at the study site. Clinicians ordering urine cultures will be educated at point‐of‐care and nudged to enter appropriate indications. The change will be championed by senior clinicians on shift. Urine culture orders will be audited, and clinicians will be provided confidential individual feedback with group comparison. This study provides a template for co‐design of theory‐informed, targeted, context‐specific, diagnostic stewardship interventions.

5. Conclusion

Stakeholder engagement has enhanced perceived acceptability of this co‐designed intervention for diagnostic stewardship of urine cultures. Behavioural change theories can strengthen co‐designed interventions by ensuring that intervention components address context‐specific drivers of low‐value tests. Emergency clinicians and researchers should leverage co‐design and behavioural change theories to develop bespoke interventions to nurture a culture of diagnostic stewardship.

Author Contributions

V.G. conceived and designed the study with advice from K.C., R.E. and T.S.G. V.G. acquired, analysed and interpreted data with input from K.C., R.E., and T.S.G. V.G. drafted the manuscript which was critically reviewed and approved by K.C., R.E. and T.S.G.

Funding

The authors have nothing to report.

Disclosure

A large language model was not used to write any part of this submission.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Supplementary Appendix S1: Diagnostic stewardship workshop pre‐reading.

A. What is diagnostic stewardship? Why do we need diagnostic stewardship?

B. What are we going to discuss? Why?

C. What are our diagnostic test options? Why these tests?

D. What are the barriers to diagnostic stewardship of the chosen test at TUH‐ED?

E. What are our options for the intervention to enhance diagnostic stewardship?

F. How to match barriers and interventions for diagnostic stewardship?

Supplementary Appendix S2: Consolidated criteria for reporting qualitative studies (COREQ) checklist*. Co‐design of a theory‐informed, multicomponent, intervention for diagnostic stewardship in a major‐referral emergency department: A qualitative descriptive study.

Supplementary Appendix S3: Table: Intervention challenges in workshops to co‐design urine culture diagnostic stewardship intervention at Townsville University Hospital Emergency Department.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author.