Approaches to evaluate the impact of diagnostic stewardship interventions have often focused on resource use and costs. However, what also needs to be determined is if diagnostic stewardship activities are leading to improved diagnosis, improved safety, or reduction of diagnostic error. We propose three approaches to that.
First, structural measures could be used to assess whether interventions affect the capacity of systems and the commitments of organizational resources and personnel to enable implementation of diagnostic stewardship. Examples could be derived from the following resources:
- The Safer Dx Checklist is a 10-item organizational self-assessment tool to assess practices that promote diagnostic safety.83 One item from the Safer Dx Checklist is particularly relevant to diagnostic stewardship: “Health care organization has in place standardized systems and processes to encourage direct, collaborative interactions between treating clinical teams and diagnostic specialties (e.g., laboratory, pathology, radiology) in cases that pose diagnostic challenges.”
- The ONC SAFER guides are a set of risk assessment tools to evaluate the safety and safe use of health IT.84,85 Several items describe recommended practices to optimize the safety of CPOE, test result reporting and tracking in electronic health records, and electronic communication between clinicians.
- Guidance is available and continues to evolve for diagnostic excellence programs in hospitals and other healthcare organizations.86,87 One specific program, Core Elements of Hospital Diagnostic Excellence, includes diagnostic stewardship as a key component and is expected to be released by the Centers for Disease Control and Prevention (CDC) and others in late 2024.88
Second, it is possible to measure change in processes from specific actions that diagnostic stewardship interventions promote. For example, changes in demand for laboratory consultation and changes in test ordering patterns are types of process changes that can help program leaders assess whether new policies and practices are being implemented as envisioned. Other examples include:
- Frequency of consultations or calls placed to the laboratory for assistance with test selection or interpretation.
- Frequency of orders for tests known to be widely overused or underused.
- Frequency of test orders found to be inappropriate or erroneous upon review by the diagnostic stewardship team.
- Contamination rates for diagnostic specimens.89
- Internal laboratory quality measures, such as the percentage of tests followed by protocol-concordant reflex testing.
Third, outcomes could be reviewed to determine whether diagnostic stewardship interventions improved diagnostic safety outcomes and reduced the risk of diagnostic errors. However, it is difficult to infer changes in safety or adverse outcomes based on test use or even inappropriate use alone. An example of a safety-related outcome is a change in diagnosis after review/intervention by a diagnostic stewardship team, which could imply a diagnostic error.
Other potential diagnostic safety outcomes include diagnostic errors in which testing-related factors are found to contribute to error. Diagnostic errors can be identified by reviewing a sample of records from the target population (e.g., patients with coagulation disorders) within a specified time period, using a structured record review process to identify missed opportunities to make a correct or timely diagnosis.90
In addition to evaluating changes in safety-related events, it is also important to assess the value, cost-effectiveness, and sustainability of diagnostic stewardship activities and programs. Ideally, approaches to assess successful implementation and outcomes should include measures of harm or clinical impact. It is also important to assess whether the benefits and consequences of diagnostic stewardship extend equitably across populations. For example, research indicates racial91 and geographic disparities in blood culture contamination.92,93 Improving the testing process may also facilitate earlier diagnosis of chronic diseases that disproportionately burden certain populations.94 Diagnostic stewardship should aim not only to improve patient outcomes but also to close these gaps and inequities.
