Effect of Diagnostic Test on Hospital Length of Stay for Patients with C difficile

A doctor checks on a patient laying in a hospital bed.
A doctor checks on a patient laying in a hospital bed.

The use of a nucleic acid assay (NAAT) for diagnosing Clostridium difficile infection demonstrated a significant reduced length of stay (LOS) for patients compared with a multi-step enzyme immunoassay-based strategy, according to data presented at the American Society for Microbiology (ASM) Microbe 2019, held in San Francisco, California, from June 20 to 24, 2019.

C difficile is the most common microbial involved in cases of healthcare-associated infection and LOS interventions can reduce exposure, leading to decreased transmission and improved patient outcomes. In a retrospective observational cohort study, the effect on inpatient LOS with respect to diagnostic method was investigated.

Patients included in the study were age ≥2 years and had a primary or secondary discharge code of C difficile infection and no hospitalization at least 90-days prior to index admission. Matched patients tested using NAAT or multi-step enzyme immunoassay were included in the analysis; each group contained 11,180 individuals. Mean LOS in patients diagnosed via NAAT were 9.51 days (95% CI, 9.34-9.68) and 10.27 days (95% CI, 10.08-10.46) for multi-step enzyme immunoassay (P <.0001).

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The reduced overall LOS observed using NAAT was significant, and according to the investigators, this was a result of the known correlations between LOS and C difficile infection transmission rates. Researchers stressed that measures aimed at reducing LOS should be part of a larger prevention strategy for C difficile infection.


Engstron-Melnyk JA, Liu C, Li Y-C, et al. Diagnostic testing choice impacts hospital length of stay for patients diagnosed with C. difficile infections – Real world evidence from the U.S. Presented at: ASM Microbe 2019; June 20-24, 2019; San Francisco, California. Poster 511.