A hard stop clinical decision support tool embedded in the electronic medical record significantly reduced repeat Clostridioides difficile toxin enzyme immunoassay, or T-EIA, testing at a hospital in St. Louis.
“Due to concern regarding the low sensitivity of toxin T-EIA tests, a common misconception exists that three sequential tests are necessary to ‘rule out’ [C. difficile infection (CDI)],” Jennie H. Kwon, DO, MSCI, assistant professor of medicine in the division of infectious diseases at Washington University School of Medicine, and colleagues wrote. “This practice has led to a decrease in the positive predictive value of each subsequent test and, therefore, to an increase in the likelihood of false-positive results.”
Unnecessary treatment resulting from false-positive T-EIA tests “can lead to adverse drug side effects, unnecessary costs, and a paradoxical increase in the risk of developing actual CDI,” the researchers wrote. They said diagnostic stewardship is one way to improve C. difficile T-EIA testing.
“Specifically, the use of a computerized clinical decision support tools [has] been shown to improve practitioner laboratory test ordering practices,” they wrote.
Between January 2015 and August 2015, the researchers enrolled all inpatients aged 18 years or older who had a C. difficile T-EIA test ordered at Barnes-Jewish Hospital. They placed a hard stop in the EMR system, which limited repeat testing within 96 hours of a negative test.
The preintervention period included 1,146 admissions and the postintervention period included 982 admissions.
During the preintervention period, 9.12 tests were conducted per 100 admissions compared with 6.94 per 100 admissions during the postintervention period (P < .01). The researchers reported that the hard stop “fired” 293 times, of which 156 were “’duplicate alerts,’ in which the alert was shown repeatedly to the same ordering provider multiple times on the same calendar day for the same patient,” Kwon and colleagues explained.
They observed no significant difference before and after the intervention in the overall percentage of all positive assays (P = .27) or in the percentage of the first test per admission that was positive (P = .56).
But there was a significant reduction in the number of admissions that included repeat tests conducted within 96 hours from an initial negative test, from 124 admissions (11%) in the preintervention period to 15 admissions (2%) after the intervention was implemented.
They observed no significant differences in the postintervention period in patient discharge location, patients who received the CDI ICD-9 code, all-cause death within 30 days or colectomy due to CDI.
“In [an] era of increasing focus on diagnostic stewardship and appropriate test utilization, this study provides evidence supporting the role of clinical decision support in improving C. difficile test utilization, regardless of whether the diagnostic method used is PCR or T-EIA,” Kwon and colleagues wrote. – by Marley Ghizzone
Disclosures: Kwon reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.