Clostridioides difficile testing in asymptomatic individuals and patients with diarrhea from other causes can contribute to unnecessary treatment of C. difficile colonization, overreporting of C. difficile infections (CDIs), and reputational damage. Reference McDonald, Gerding and Johnson1,Reference Rock, Pana and Leekha2 We created a survey to investigate strategies used by acute-care hospitals in the Society for Healthcare Epidemiology of America Research Network (SRN) to reduce unnecessary C. difficile testing, reporting, and treatment.
Methods
Design and participants
A 14-item survey was created using MagnetMail and was e-mailed to SRN members. Respondents were asked to consider their institution’s practices for C. difficile testing in adult patients only. The questionnaire recorded demographic characteristics of respondent institutions; C. difficile test ordering, processing, and reporting practices; and antimicrobial stewardship program (ASP) activities related to C. difficile testing.
The survey was first distributed on February 18, 2020. Due to a low response rate because of the COVID-19 pandemic, the survey was temporarily suspended. We then sent reminder e-mails on September 24 and 29, 2020. Responses were accepted between February 18 and October 5, 2020. Survey results were analyzed using JMP Pro 14 (SAS, Cary, NC). We used the Fisher exact test to compare respondents that reported reduction in unnecessary C. difficile treatment against those that did not.
Results
Respondent demographics
Of the 95 SRN members, 50 completed the survey, for a response rate of 53%. Most respondents (92%) were based in the United States or Canada. Of the 50 respondents, 25 (50%) represented an academic medical center and an additional 13 (26%) indicated that their institution has an academic affiliation. Approximately half of responding hospitals had ≤500 beds, 32% reported 501–1,000 beds, and 10% reported >1,000 beds. Of the 41 individuals who responded on behalf of their institution, 36 reported a role in healthcare epidemiology, 3 reported a role in antimicrobial stewardship, and 1 reported a role in clinical microbiology. Table 1 summarizes survey responses. Detailed responses are available in the Supplementary Material (online).
Table 1. Summary of Survey Responses

a Other topics reported: “asymptomatic admission screening for all adult patients”; “no repeat testing in 7d interval”; “avoid testing in infants”; “more aggressively seek testing within first 48 h”; “r/o other causes of diarrhea first in non–critically ill patients”; “do not test for cure.”
b Other trainees reported: medical students, pharmacy and physician assistant trainees.
c Other staff reported: laboratory personnel.
d Other types of training reported: “order sets”; “e-mail”; “e-mail blast”; “phone”; “print”; “electronic dissemination of education materials”; “management guide, poster, cheat card for nurses.”
e Other message topics reported: “not allowed to repeat negative <7 d; or positive <30 d”; “call infectious diseases staff if ordering the test on child aged <2 y”; “avoid testing infants aged <12 mo”; “at least 3 liquid stools in last 24 h.”
f Other parameters used for hard stop: “<3 diarrheal stools in past 24 h”; “after third hospital day.”
g Other laboratory-based rejection criteria: “sooner than 7 d”; “no repeat test within 7 d of a negative result or 30 d of a positive result without prior authorization”; “repeat testing with a prior positive during the same hospitalization”; “laxative use in 48 h, <3 unformed stools in 24 h before test ordered, repeat testing within 7 d for past negative and within 14 d past positive test”; “repeat testing within 1 week”; “Bristol stool chart”; “if tested <7 d without discussion with microbiology staff; “age <3 y, test within 4 d, positive within 2 weeks”; “repeat within 7 d”; “laxatives, enema”; “age ≤1 y, positive test with 14 d, negative test within 4 d.”
Clostridioides difficile test ordering
Most respondents (80%) reported that their hospital had published indications for ordering C. difficile tests and had provided training related to C. difficile testing to residents (82%), nurses (80%), and attending physicians (74%).
When an electronic C. difficile order is placed, 62% reported that users encounter a best practice advisory (BPA) that provides information about indications for C. difficile ordering. Also, 14 (28%) implemented a “hard stop” that blocks repeat C. difficile orders or testing in the setting of laxative administration.
Laboratory processing of C. difficile tests
Most respondents (88%) reported that their laboratory cancels C. difficile orders when formed stool is submitted. Half (n = 25) reported that the laboratory performs C. difficile toxin NAT alone. The other half (n = 25) reported using a multistep algorithm: GDH/toxin combination assay reflexed to C. difficile toxin NAT (n = 13); positive NAT reflexed to C. difficile toxin EIA (n = 8); another algorithm (n = 4). Also, 17 of 50 respondents (34%) affirmed that laboratory-issued C. difficile test reports counsel providers to consider C. difficile colonization in patients who test negative for C. difficile toxin and to reassess the need for treatment.
Antimicrobial stewardship activities related to C. difficile testing
Half of the respondents reported that their ASP monitors or acts on positive C. difficile test results. One-third (34%) indicated that their ASP performs audit and feedback based on positive test results. ASPs in hospitals that use a multistep algorithm performed audit and feedback at a similar rate compared to ASPs in hospitals that did not (36% vs 33%; P = .84).
Perceived effect of the interventions used to improve C. difficile testing and treatment
Most (76%) respondents reported that their efforts to optimize C. difficile testing reduced C. difficile incidence at their institution, but only half felt that they reduced unnecessary treatment. There was no difference among respondents that reported reduction of unnecessary C. difficile treatment (n = 28) compared to those who did not (n = 6), in their reported use of a soft stop; use of a hard stop; and ASP intervention.
Discussion
Inappropriate C. difficile testing is common at acute-care hospitals and has numerous consequences. Reference McDonald, Gerding and Johnson1,Reference Rock, Pana and Leekha2 Reducing unnecessary testing at the ordering stage is ideal because it averts wasted downstream efforts involving specimen collection and test processing. In our survey, 62% of respondents reported providing clinical decision support when orders were placed but only 28% reported use of a “hard stop.” Although various investigators have reported that implementation of a “soft stop” or a “hard stop” can reduce inappropriate C. difficile testing, Mizusawa et al Reference Mizusawa, Small and Hsu3 sequentially used both and reported that “hard stops” may be more effective than “soft stops” at mitigating inappropriate orders. Reference Mizusawa, Small and Hsu3–Reference Madden, German Mesner, Cox, Mathers, Lyman, Sifri and Reduced6
The laboratory can also help to mitigate unnecessary C. difficile testing. As recommended in published guidance, 90% of respondents reported that their laboratory cancels C. difficile orders on formed stool. Reference Pillai7 A smaller group (9 of 50, 18%) reported that their laboratory rejects samples based on recent history of C. difficile testing.
Once a C. difficile test has been processed, there may still be opportunities to prevent unnecessary treatment. Half of our respondents described using a multistep algorithm that includes toxin EIA and affirmed that laboratory-issued C. difficile test reports advise providers to consider the possibility of colonization in toxin-negative patients. The clinical relevance of NAT-positive, toxin-negative C. difficile cases continues to be studied. Reference Polage, Gyorke and Kennedy8 In a case-control study involving 4,878 patients diagnosed with CDI using a GDH-based algorithm, Guh et al Reference Guh, Hatfield and Winston9 reported that toxin-positive cases were more severe and experienced CDI-related complications more frequently than patients who tested positive by NAT only. However, 49 of the toxin-negative cases developed toxic megacolon, and 8 required a colectomy. Although patients who test toxin negative may be less likely to develop severe disease or complications, the absence of toxin does not exclude the possibility of either. Reference Polage, Gyorke and Kennedy8,Reference Guh, Hatfield and Winston9 This nuance should be clear in laboratory report verbiage, and test results should always be interpreted in conjunction with clinical findings.
In the current survey, only one-third of respondents reported that their ASP performs audit and feedback based on positive C. difficile tests. The role of ASP in C. difficile management has been evolving and reports of active ASP interventions to date have been sparse. In a single-center quasi-experimental study of 208 patients being treated for CDI, Hecker et al Reference Hecker, Son, Alhmidi, Wilson, Wiest and Donskey10 reported a modest reduction in mean days of unnecessary CDI treatment after implementing audit and feedback on positive C. difficile test results (1.4 days vs 0.4 days; P = .02).
This study has several limitations. With only 50 respondents, the sample size was small. Also, 76% of respondents identified themselves as an academic medical center or an institution with an academic affiliation, which may limit generalizability of our findings to nonacademic hospitals.
In summary, this survey showed that while C. difficile diagnostic stewardship interventions were common, strategies that actively block inappropriate C. difficile orders were uncommon as was active intervention of ASPs on C. difficile test results. Institutions that have not successfully reduced reported C. difficile rates using educational interventions and “soft stop” BPAs may wish to consider methods that actively block inappropriate test orders.
Supplementary material
To view supplementary material for this article, please visit https://doi.org/10.1017/ice.2021.133
Acknowledgments
We thank Valerie Deloney from SHEA for her contribution to the survey, its distribution, and summary of results.
Financial support
No financial support was provided relevant to this article.
Conflicts of interest
All authors report no conflicts of interest relevant to this article.