How Diagnostic Stewardship Can Fight Hospital-Acquired Infections

By Dana Edwards, Matt Farmer, and Patrick Horine

Antimicrobial stewardship has been widely used and discussed in healthcare quality circles for years, as it has been shown to be effective in reducing rates of hospital-acquired infections. Can the same be said of diagnostic stewardship? According to a recent report by the World Health Organization, “the concept of diagnostic stewardship is yet to be fully recognized and embedded within regular clinical practice” (World Health Organization, 2016). For now, diagnostic stewardship remains an emerging art and science. We are learning that practitioners can improve healthcare outcomes relatively rapidly by focusing on testing specific patients at specific times for specific conditions.

Diagnostic stewardship confronts one of the biggest unspoken issues in healthcare: overutilization of services. Laboratory testing is one area where overutilization is quite common. A 2016 study of laboratory tests found that a single hospital, New York University Langone Medical Center, automatically ordered daily lab tests for more than 95% of its internal medicine patients “without any requirement to review the appropriateness of the test.” By simply eliminating automated approvals, the hospital was able to cut down on testing by 8.5% (Iturrate, Jubelt, Volpicelli, & Hochman, 2016).

Diagnostic stewardship elaborates on this process, drilling down to specific tests that physicians may order routinely and without thought. It pays specific attention to tests where a lack of intervention may drive up costs and further complicate patient outcomes, namely those that may prompt doctors to order completely unnecessary drugs or treatments.

CoxHealth Branson Medical Center is part of CoxHealth, a six-hospital healthcare system in Southwest Missouri. In 2017, the medical center began using diagnostic stewardship with a focus on managing cases of Clostridium difficile, more commonly known as C. diff, which manifests itself primarily as an infection of the lower digestive system. In its most serious form, C. diff can lead to severe diarrhea, colitis, and even death. Hospital-acquired C. diff is often triggered by the use of broad-spectrum antibiotics, which can wipe out delicate bacteria in the digestive system, leading to the infection.

Incidents of C. diff are costly for the U.S. healthcare system. A study published in November 2015 in the American Journal of Infection Control concluded that a hospital patient who develops a case of C. diff costs 40% more to treat than a patient who does not contract such an infection, or an additional $7,285 per patient (Magee et al., 2015). Researchers from the drug manufacturer Merck & Co. estimated that C. diff costs the U.S. healthcare system $5.4 billion per year (Lutz, 2018).

Most cases of C. diff are treated similarly: The first step is treatment with another antibiotic. Surgery is an option in severe recurrent cases, and some physicians have begun to recommend fecal transplants in order to replenish the gut bacteria lost from the first round of antibiotic treatments. However, not all patients who have the bacteria in their stool are suffering from an infection, and not all symptoms are confirmation of the presence of an infection. Officials at CoxHealth Branson adjusted their use of diagnostics accordingly.

The motivation for this program arose from the work CoxHealth had done with its accrediting body, DNV GL Healthcare. This agency requires the hospitals it accredits to focus on continuous improvement of quality of care and patient outcomes. As a result, DNV GL surveys its hospitals annually as opposed to triennially. This approach keeps managers motivated to systematically find ways to improve patient care. DNV GL also uses a form of the ISO 9001 quality control system that has been adapted specifically for hospital benchmarking purposes.

To that end, CoxHealth Branson began a new protocol called a “charge nurse hard stop.” The charge nurse was empowered with stopping the remittance of any stool samples for lab testing under the following guidelines:

  • Was there any known cause for the patient’s diarrhea, such as being prescribed a laxative?
  • Did the patient have a prior history of diff?
  • Is the patient currently being treated for diff?
  • Did the patient have symptoms of infection, such as an elevated white cell blood count or stomach pain?

If the patient was prescribed a laxative, it was stopped. If the diarrhea resolved, further testing was not required. And when there were no symptoms of infection, discussions with the physician were needed to determine other possible causes for the patient’s diarrhea, such as medications or diet. Meanwhile, a positive test result within the first three days of admission meant any occurrence of C. diff, while still warranting immediate treatment, would not be considered a hospital-acquired infection.

A top priority at CoxHealth Branson was preserving patient safety by reducing the number of infections; another was to reduce the medical center’s standardized infection ratio (SIR), defined as the predicted rate at which cases of C. diff should occur, given the hospital’s inpatient volume, patient acuity, and various other factors.

The new diagnostic stewardship protocol was introduced at the end of the first quarter of 2018. During that quarter, CoxHealth Branson had nine reported cases of hospital-onset C. diff, and an SIR of 1.862, or about 54% higher than predicted. Although the cases and SIR fluctuated in the intervening quarters, during the second quarter of 2018, CoxHealth Branson reported just two cases of hospital-onset C. diff. Its SIR had dropped to 0.517, or about 52% below what its predicted number of infections should have been. The most current SIR data, for third quarter 2018, stands at 0.374, about 63% lower than the predicted number of infections for that quarter. These numbers show that the new process has not only brought significant results, but is also sustainable.

Of course, diagnostic stewardship does not have to be limited to fighting a single hospital-acquired infection or condition. Used creatively and appropriately, it can do much to improve patient outcomes and quality of care.

Dana Edwards is an infection preventionist with CoxHealth Branson Medical Center in Branson, Missouri, and Matt Farmer is its director of critical care and emergency services. Patrick Horine is the president of DNV GL Healthcare.


Iturrate, E., Jubelt, L., Volpicelli, F., & Hochman, K. (2016). Optimize your electronic medical record to increase value: Reducing laboratory overutilization. The American Journal of Medicine, 129(2), 215–220.

Lutz, R. (2018, March 21). Health care resources cost recurrent C. difficile patients more. MD Magazine. Retrieved from

Magee, G., Strauss, M. E., Thomas, S. M., Brown, H., Baumer, D., & Broderick, K. C. (2015). Impact of Clostridium difficile-associated diarrhea on acute care length of stay, hospital costs, and readmission: A multicenter retrospective study of inpatients, 2009-2011. American Journal of Infection Control, 43(11), 1148–1153.

World Health Organization (2016). Diagnostic stewardship: A guide to implementation in antimicrobial resistance surveillance sites. Retrieved from