By Gina Shaw
Molecular rapid diagnostic testing (RDT) has become an essential component of hospital infectious disease management, but it is most effective with antimicrobial stewardship program (ASP) intervention, said Ashlan J. Kunz Coyne, BS, PharmD, MPH, at the 2024 Making a Difference in Infectious Disease (MAD-ID) conference in Orlando, Fla.
Dr. Kunz Coyne, an assistant professor of clinical and translational science in the Department of Pharmacy Practice & Science, University of Kentucky College of Pharmacy, in Louisville, cited a recent systematic review and network meta-analysis, using results from studies of patients with bloodstream infection with the aim of comparing the clinical impact of RDT with conventional blood cultures, both assessed with and without ASP, on outcomes including mortality, hospital length of stay (LOS) and time to optimal therapy (Clin Infect Dis 2024 Apr 27, ciae234).
The study found that RDT combined with ASP had a significant mortality benefit compared with ASP versus blood culture alone (odds ratio [OR], 0.72) as did RDT plus ASP compared with blood culture plus ASP (OR, 0.78). Neither RDT alone nor blood culture plus ASP showed a significant survival benefit compared with culture alone, according to Dr. Kunz Coyne.
RDT combined with ASP also reduced LOS (P=0.91), while no difference in LOS was shown in any other groups. Time to optimal therapy also was improved with RDT plus ASP compared with culture alone (29 hours shorter), culture plus ASP (18 hours shorter) and with RDT alone (12 hours shorter).
“This strongly supports the idea that the positive impact of RDTs on patient outcomes and cost-effectiveness is dependent on coordinated stewardship intervention,” Dr. Kunz Coyne said. “But available studies weren’t designed to discuss the processes that facilities are using with RDT, and don’t evaluate which of these processes work best. That’s the humbling nature of RDT integration: the heterogeneity of each institution.”
Dr. Kunz Coyne discussed the following FDA-approved blood diagnostic assays in her presentation and noted that differences in turnaround times may be the result of some assays being direct from blood:
- Verigene BC-GP and BC-GN (Nanosphere), which provide bacterial identification in under 2.5 hours;
- BioFire FilmArray BCID (BioFire Diagnostics), which provides bacterial and fungal identification in approximately one hour;
- T2 Biosystems’ T2 Candida, which provides fungal identification in three to seven hours;
- T2 Biosystems’ T2 Bacteria, which provides bacterial identification in three to seven hours; and
- ePlex (Roche Diagnostics), which provides bacterial and fungal identification in approximately one hour.
- Accelerate Pheno (Accelerate Diagnostics), the only currently approved blood diagnostic assay to provide both bacterial and fungal identification as well as antibiotic susceptibilities, with identification in approximately two hours and susceptibilities in approximately seven hours (PLoS 2013;10[7]:e1001478; J Clin Microbiol2015;53[8]:2460-2272; J Clin Microbiol 2013;51[12]:4130-4136; Ann Intern Med 2019;170[12]:845-852; Diagn Microbiol Infect Dis 2017;89[1]:52-57).
“Challenges that impact your mRDT [molecular RDT] workflow and ability to have a positive impact on patient outcomes and cost-effectiveness with these tests include your choice of platform and protocol for that platform, how you are alerted to results, how response is initiated, and how everything is documented,” Dr. Kunz Coyne said.
She shared several examples of alert and action algorithms from different institutions that address key questions, including who is contacted and how they are contacted when the microbiology lab has an alert (such as inbox messaging in Epic or Theradoc), frameworks for therapy selection, and guidelines for whose responsibility it is to act on an alert and how to make a therapeutic change if warranted.
“These algorithms can guide the pharmacist to the preferred treatment for the institution based on the mRDT result, and ideally are user-intuitive for the pharmacist,” Dr. Kunz Coyne said. “Some institutions will incorporate into algorithms standing orders for automatic therapeutic interchange. That way, when a result comes in that warrants therapeutic escalation, the pharmacist can put in at least a one-time order to escalate instead of waiting for a consult and approval and delaying time to effective therapy.”
Dr. Kunz Coyne reported no relevant financial disclosures.
