Clinical decision support in EMRs is key to optimizing GI multiplex PCR panels

Commercially available gastrointestinal (GI) multiplex PCR testing panels detect bacterial, viral, and parasitic pathogens with high sensitivity and specificity. Compared with standard stool cultures, these panels have been associated with higher positive yield, reduced antibiotic use, decreased time to initiation of optimal antibiotic therapy, decreased length of hospital stay, and fewer diagnostic procedures.

However, some research has found overuse of the panels because of high false-positive rates and low pre-test probability for infection ideology of diarrhea in hospital settings, and because re-testing often responds to residual genetic material or colonization.

Seeking to understand how to improve utilization and maintain key benefits to patient care, Veterans Administration (VA) researchers performed a retrospective analysis of the impact of a clinical decision support (CDS) system within the electronic medical record (EMR) intended to drive appropriate use of the BioFire FilmArray GI panel.

The researchers reported that the CDS decreased testing and inappropriate ordering, based on use of laxatives or undocumented diarrhea within the VA Maryland Healthcare System (Antimicrob Steward Healthc Epidemiol 2024; doi: 10.1017/ash.2024.15).

In the study, a “soft stop” reminder at the point of ordering asked clinicians to confirm five appropriateness criteria. They were documented diarrhea, no recent receipt of laxatives, confirmation that C. difficile was not the leading suspected cause of diarrhea, passage of more than 14 days since a prior positive test or a prior positive test more than 4 weeks ago, and hospitalization duration less than 72 hours. Orders with unmet criteria required approval by a diagnostic stewardship consultant.

A second question asked whether the GI panel was indicated and if not, called for reassessing need for testing within 24 hours, testing only for C. difficile, or continuing high clinical suspicion for GI infection or high risk for complications despite not meeting all five criteria.

Researchers compared the number of tests performed in pre- and post-CDS implementation groups using Chi square and one-way analysis of variance tests. They also performed a bivariate binomial regression on process and outcome measures to calculate an incidence rate ratio (IRR) comparing pre- and post-intervention rates, using 2-week periods as the unit of analysis. Patients were mostly male (80.2%) and of mean age 60.2.

Importantly, they found a 39% reduction in GI panel orders between the pre- and post-CDS periods, consistent with a 39% reduction in ordering (IRR 0.61). Ordering decreased for both inappropriate and appropriate tests, perhaps reflecting a general lack of awareness on how to order the test following the change in ordering practice.

However, the inappropriate testing among patients on laxatives decreased significantly following introduction of the CDS (IRR 0.37), and inappropriate testing for patients without documented diarrhea also trended toward significance (IRR 0.25). These results suggest that the “soft stop” advice provided via CDS positively impacted the decision to order a GI panel, the researchers noted.

Half of GI panel orders completed during the study period met at least one criterion for inappropriate ordering. The primary reason for inappropriate ordering was a concomitant C. difficile PCR test (33.3%). The CDS did not clarify that the GI panel included C. difficile testing. More provider education may decrease duplicate ordering going forward, the researchers noted.

They identified 9 distinct pathogens, with C. difficile and Norovirus being the most frequent. The mean length of stay among the 69 hospitalized patients was 8.8 days and did not differ between the pre- and post-CDS periods. About half of orders were from outpatient settings (51.8%), and nearly a third were from inpatient settings (30.3%).

The researchers suggested starting efforts to reduce inappropriate ordering with ambulatory providers. Suggested efforts included limiting use of the GI panel as part of the diagnostic work-up for chronic diarrhea.

GI panels for outpatients with chronic diarrhea of several years is likely a low yield testing strategy, the researchers added.

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