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Annual Perspective

Patient Safety in the Ambulatory Care Setting

August 5, 2022 
View more articles from the same authors.

Schiff G, Mossburg SE, Dowell P, et al. Patient Safety in the Ambulatory Care Setting. PSNet [internet]. Rockville (MD): Agency for Healthcare Research and Quality, US Department of Health and Human Services. 2022.


Schiff G, Mossburg SE, Dowell P, et al. Patient Safety in the Ambulatory Care Setting. PSNet [internet]. Rockville (MD): Agency for Healthcare Research and Quality, US Department of Health and Human Services. 2022.


There is no way to review the year 2021 in quality and safety of ambulatory care without contemplating the myriad of ways in which the COVID‑19 pandemic affected patients, practitioners, offices, and organizations, as well as health policy and society. The shift in priorities toward fighting the pandemic made it a challenging year for patient safety research. Although the evidence generation and publication process was rapidly accelerated for pandemic-related research, most academic safety research published in 2021 did not yet reflect the daily realities that ambulatory care—especially primary care practices—faced during the second year of the pandemic. The rapidly changing epidemiology of the virus, and the energy and resources that, by necessity, were redirected from academic pursuits to emergency endeavors, augmented this gap. Fortunately, aspects of the emergency responses to the COVID‑19 pandemic, such as maintaining adequate access to ambulatory care and reliable diagnostic services, have been informed by lessons from the past three decades of quality and safety work.1 At the same time, the COVID‑19 crisis affords the opportunity to reboot, rethink, and reorient priorities and approaches to ambulatory care safety in the future.2,3

The more things change, the more the same core themes continue to stand out for their importance to reliable, patient-centered, high-quality ambulatory healthcare services. Thus, we have chosen to highlight in this Perspective several key themes from the past year’s research findings, which are featured on the AHRQ PSNet website. The selection of these features was driven by (1) areas addressed by the largest number of key studies and commentaries on PSNet over the past year and (2) core areas (often cross-cutting) that are fundamental for patient safety research and progress. Specifically, we highlight recent work in diagnostic safety, which continues to be a subject of importance and a major challenge in ambulatory care, as highlighted in the 2015 report Improving Diagnosis in Health Care4 from the National Academy of Medicine and a recent study that identified key research priorities for improving diagnostic safety.

While there are a variety of safety issues in the ambulatory care setting, diagnostic-related errors are among the most problematic and the most common medical errors.5,6 Diagnostic safety is also one of the major challenges in assessing and caring for COVID patients, including making the correct diagnosis of COVID‑19, accurately diagnosing complications, and sorting out symptoms that may or may not be post-COVID‑19 symptoms. Alongside the diagnostic challenges navigated by ambulatory care providers during the pandemic, we discuss innovations in the field through the use of telehealth, an area of ambulatory care that has expanded since the pandemic began. Next, we discuss findings regarding ongoing issues that affect diagnostic safety, which are not centered around the impact of the COVID‑19 pandemic, as well as several strategies to improve safety in ambulatory care. For this Perspective, we benefited from the input and insights of Gordon Schiff, MD, the Quality and Safety Director for the Harvard Medical School Center for Primary Care. Dr. Schiff has worked extensively in ambulatory care and diagnostic safety.

COVID-19: Challenges and Innovations in Patient Safety

Early in the pandemic, primary care providers faced the challenge of diagnosing COVID‑19, in addition to treating it. Available diagnostic tests have trade‑offs. Antigen tests offer rapid results for diagnosing illness, but at the cost of some accuracy, while polymerase chain reaction (PCR) tests, which have higher accuracy, take longer to obtain results. Antigen tests have the potential to yield false negatives for a variety of reasons, such as testing too soon after exposure or inadequate sampling, with variation in sensitivity among available tests.7 Alternatively, false positive results could occur with antigen tests, so healthcare providers were encouraged to do routine follow-up testing (reflex testing) with PCR testing when appropriate, and to consider the expected occurrence of false positive results when interpreting test results in their patient populations. For patients, false positives resulted in unnecessary quarantine away from loved ones and from work, while false negatives resulted in ongoing, unknown spread of the virus.

Beyond the diagnostic challenges, patient safety was critically impacted by burnout, stress about COVID‑19 exposure and infection, and the resulting high turnover rates among healthcare workers. Not surprisingly, researchers found that healthcare workers who are experiencing burnout, or new staff who are learning new responsibilities as a result of turnover, may be more prone to missed and delayed diagnoses, outright diagnostic errors, and medical errors in general, thereby increasing the risks to patient safety. Times of crisis can also create new opportunities and inspire rapid problem-solving and innovation. For example, health information technology (HIT)-based solutions for infection prevention that were underutilized for years were included in rapid-response HIT solutions and quickly implemented during the COVID‑19 pandemic. Telehealth in particular served as the only option for ambulatory care for many clinical (e.g., rural) sites and for various outpatient specialties.8 However, telehealth workflow challenges were accelerated during the COVID‑19 pandemic. Common challenges encountered include unstable Wi-Fi connections, lack of broadband access, limited digital literacy among many older patients and other underserved patient populations, inadequate access to translation services, and concerns with health privacy. These challenges must be addressed if telehealth is to be deployed effectively and fairly to all patients, including those with the greatest need, in what will be a forever changed post-pandemic world.

Diagnostic Safety

Failure to Close the Loop on Diagnostic Testing and Referrals

While the issues that arose because of the COVID‑19 pandemic impacted diagnostic safety, research on safety this year underscored other issues negatively affecting diagnostic safety that are independent of, but may be exacerbated by, the pandemic. For example, referring clinicians rely heavily on the information they receive from specialists when they request a consultation for a specific patient condition. This process, known as the “diagnostic referral loop,” helps clinicians select the best treatment options for their patients. Closing this loop involves arranging for an ordered test to be scheduled and completed, so that the original referring provider has access to the information necessary for appropriate diagnosis and treatment. However, some studies report nearly 75% failure rates in closing the diagnostic referral loop. Low-reliability process designs, including ineffective reminders (to both patients and providers) and limited utilization of information technology, contribute to suboptimal diagnostic referral completion rates and delays.

Other loop closure failures, such as suboptimal communication, lack of test result management, and failure to follow up on laboratory findings, can lead to missed or delayed diagnoses, subsequent delays in treatment, or even erroneous treatment, any of which may lead to patient harm. Follow-up failures (i.e., incomplete or delayed communication of test results) have been documented across a wide spectrum of abnormal test results. Such failures could consist of clinicians overlooking abnormal, but non-life-threatening, test results and/or not communicating these results to a patient—but they can also include potentially lethal failures in communication that prevent or delay lifesaving treatments.

Delays in Cancer Diagnosis

Several studies published this year emphasized challenges caused by delays in cancer diagnosis. Missed or delayed diagnostic opportunities resulting from non-timely primary care referrals are another source of errors, with missed and delayed diagnoses of cancer outnumbering the next leading type of errors (treatment errors) by a factor of six to one.9 In a retrospective study conducted in 2021 in England, investigators researched the time to diagnosis for individuals with a known diagnosis of urological cancer to identify how many of these individuals would have been considered high risk prior to their diagnosis based on their symptoms. Of the patients in this study who qualified for expedited referral, more than one-quarter did not receive a timely diagnosis. The authors highlighted the need to address non-timely diagnoses by ensuring that referrals adhere to guidelines for reacting to defined, cancer-specific symptoms; they concluded that adherence to these guidelines represents a significant opportunity for improving both the diagnostic process and patient outcomes.

Diagnostic errors and missed or delayed diagnostic opportunities undermine the benefit of early diagnosis and treatment for a variety of conditions; however, diagnostic errors in oncology may be particularly consequential—clinically, psychologically, and legally. For example, diagnostic errors in oncologic radiology make up the majority of malpractice cases for diagnostic failure allegations in the field of radiology. In addition, compared with allegations of diagnostic errors for non‑oncologic radiology cases, oncologic radiology cases are more likely to be associated with high-severity harm as well as clinically relevant missed or delayed treatment opportunities. While early diagnosis is important, a review of lung cancer screening by the US Preventive Services Task Force (USPSTF) found that use of low-dose computed tomography screening can reduce lung cancer mortality but is also associated with harms (e.g., radiation exposure, false-positive results , psychological consequences such as anxiety).10

Further, closing the gap on missed and delayed diagnostic events may create opportunities to address known disparities in cancer diagnosis and outcomes. Research has repeatedly identified racial disparities in cancer staging (early vs. late) and outcomes. Black women are more likely to experience delays in diagnosis compared with White women. Black women experience at least twofold increased odds of delay in the diagnostic process overall and, specifically, delay in diagnostic evaluation and biopsy. A systematic review revealed that women of ethnic minority and lower educational attainment were less likely to receive appropriate follow-up care after abnormal mammograms. Although Black and White women have similar breast cancer incidence rates, the mortality rate for Black women with breast cancer is 42% higher than that of White women with breast cancer. Among women under the age of 45, the mortality rate among Black women with breast cancer is twice as high as the rate among White women with breast cancer.

Enhancing Patient Safety in the Ambulatory Care Setting

Several strategies to enhance patient safety in the ambulatory care setting were highlighted this year. For example, clinician peer input can affect diagnostic accuracy and confidence, particularly in situations involving a high degree of diagnostic uncertainty. Another potential approach to improve diagnostic accuracy was highlighted in the study by Pohl et al. (2021), which used the Delphi method to identify “Green Flags”, or symptoms that increase the likelihood that a headache is a primary rather than a secondary headache. The authors note that the novel approach of combining Green and Red Flags when considering a diagnosis may increase diagnostic accuracy, although more work is needed to validate this approach and expand to other clinical areas.11 Laboratories are also an important component of the diagnostic process, and there are well-described steps that laboratories can take to reduce or prevent diagnostic errors. These steps include leveraging advances in HIT to support or refute unexpected lab findings; using tracking systems for electronic health record (EHR) notifications; improving communication among laboratory professionals, other healthcare providers, and patients; and using diagnostic result management modules in EHRs, anchored in team approaches, to support more reliable tracking of, and follow-up on, diagnostic test results. In theory, these strategies should represent “low-hanging fruit” (compared to the many cognitive challenges involved in considering and making an accurate, timely diagnosis); however, they remain challenging and progress to date on decreasing diagnostic errors falls short of Six Sigma-quality levels demanded in other industries (e.g., approximately one defect per million).

Event reporting can also be a useful way to identify system vulnerabilities and design effective interventions to improve safety. Structural and behavioral factors can contribute to adverse events among patients, and patient safety reports in ambulatory care settings should capture both of these factors. Engaging patients in the process may help as well. A study of patients with access to open notes from ambulatory care reported that 20% of patients who read a clinical note reported an error, and the most common category of error was diagnosis. Encouraging patients to be involved in event reporting may lead to increased accuracy of ambulatory care records, improved outcomes, and patient engagement in safety efforts.

An organizational culture of safety balances the role of individual accountability within the larger context of understanding underlying systemic vulnerabilities. While guidance on how to create an organizational culture of safety exists, implementation has yet to reach its full potential. Ambulatory care settings need dedicated time, training, incentives, support, and resources to achieve these ideals. AHRQ Surveys on Patient Safety Culture™ continue to show that substantial numbers of staff are afraid to report safety problems. One way to foster change is for health delivery systems to leverage their infrastructure and facilitate the creation of ambulatory care safety programs. Ideally, such health delivery systems could become learning centers to test and implement safety strategies in their satellite ambulatory care settings and, ultimately, extend this programming to local and regional practices.

Next Steps in Ambulatory Care Safety

Over the last three decades, many lessons have been learned and many innovative ideas have been generated in quality improvement and patient safety, yet we have not fully evaluated all the strategies available. AHRQ supports ongoing funding opportunities to sponsor large research demonstration and implementation projects in many of the areas touched upon in this Perspective. These demonstration and implementation projects could further accelerate the application of lessons learned to help safety leaders better understand and, ultimately, decrease adverse events in ambulatory and long term care settings.12 One recent funding opportunity, Making Health Care Safer in Ambulatory Care Settings and Long Term Care Facilities (R18), prioritizes projects that focus on the implementation of evidence-based processes to improve patient safety, especially those involving transitions in care, and the funding cycle will be active through 2024. Another funding opportunity supported by AHRQ are the projects that establish Centers for Diagnostic Excellence. Potential benefits of these projects include renewed interest in new and well-established patient safety practices (PSPs), such as infection prevention-related PSPs to address the threat of emerging multidrug-resistant organisms. In addition, emerging PSPs that are intended to address well-established harms are being investigated, such as the increasing use of clinical decision support tools to reduce diagnostic errors.

Gordon Schiff, MD
Associate Director
Brigham and Women’s Center for Patient Safety Research and Practice
Boston, MA

Sarah E. Mossburg, RN, PhD
Senior Researcher
American Institutes for Research
Crystal City, VA

Paul Dowell, PharmD, PhD
Senior Researcher
American Institutes for Research
Columbia, MD

Erica Shelton, MD, MPH, MHS
Principal Researcher
American Institutes for Research
Washington, DC
Assistant Professor
Department of Emergency Medicine
Johns Hopkins University School of Medicine
Baltimore, MD


1. Zipperer L. COVID‑19: Team and human factors to improve safety. PSNet Primer. 2020.

2. Schiff G, Shojania KG. Looking back on the history of patient safety: an opportunity to reflect and ponder future challenges. BMJ Qual Saf. 2021;31:148-152. doi:10.1136/bmjqs-2021-014163.

3. Nimako K, Kruk ME. Seizing the moment to rethink health systems. Lancet Glob Health. 2021;9(12):e1758-e1762. doi:10.1016/S2214-109X(21)00356-9\

4. National Academies of Sciences, Engineering, and Medicine. Improving diagnosis in health care. The National Academies Press; 2015.

5. Saber Tehrani AS, Lee H, Mathews SC, et al. 25-Year summary of US malpractice claims for diagnostic errors 1986-2010: an analysis from the National Practitioner Data Bank. BMJ Qual Saf. 2013;22:672-680.

6. Newman-Toker DE, Wang Z, Zhu Y, et al. Rate of diagnostic errors and serious misdiagnosis-related harms for major vascular events, infections, and cancers: toward a national incidence estimate using the “Big Three.” Diagnosis (Berl). 2021;8(1):67-84. doi:10.1515/dx-2019-0104.

7. Dinnes J, Deeks JJ, Berhane S, et al. Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection. Cochrane Database of Systematic Reviews 2021.

8. Sikka N, Willis J, Fitall E, Hall KH, et al. Telehealth and patient safety during the COVID-19 response. PSNet Annual Perspective 2020.

9. Schiff GD, Puopolo AL, Huben-Kearney A, et al. Primary care closed claims experience of Massachusetts malpractice insurers. JAMA Intern Med. 2013;173(22):2063-2068.

10. Jonas, DE, Reuland DS, Reddy SM, et al. Screening for Lung Cancer with Low-Dose Computed Tomography Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2021;325(10):971-987.

11. Pohl H, Do TP, García-Azorín D et al. Green Flags and headache: A concept study using the Delphi Method. Headache. 2021;61:300–309.

12. Hall KK, Shoemaker-Hunt S, Hoffman L, et al. Making healthcare safer III: a critical analysis of existing and emerging patient safety practices. AHRQ Publication No. 20-0029-EF. Agency for Healthcare Research and Quality; 2020.



This project was funded under contract number 75Q80119C00004 from the Agency for Healthcare Research and Quality (AHRQ), U.S. Department of Health and Human Services. The authors are solely responsible for this report’s contents, findings, and conclusions, which do not necessarily represent the views of AHRQ. Readers should not interpret any statement in this report as an official position of AHRQ or of the U.S. Department of Health and Human Services. None of the authors has any affiliation or financial involvement that conflicts with the material presented in this report. View AHRQ Disclaimers

Schiff G, Mossburg SE, Dowell P, et al. Patient Safety in the Ambulatory Care Setting. PSNet [internet]. Rockville (MD): Agency for Healthcare Research and Quality, US Department of Health and Human Services. 2022.

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