2351. Rate and Consequences of Missed Clostridioides (Clostridium) difficile Infection Diagnosis from Non-disclosure of Clostridioides difficile Multiplex PCR Results. Two-Hospital Experience

BACKGROUND: It is common practice among microbiology laboratories in the United States to blind the BioFire FilmArray GI Panel results for Clostridioides (Clostridium) difficile (C. difficile) in fear of over-diagnosis of C. difficile infection (CDI). METHODS: We conducted a retrospective cohort study in 2 tertiary academic centers in New York to examine the rate of missed CDI diagnosis and the associated adverse outcomes from blinding the BioFire FilmArray GI Panel results for C. difficile. Of note, in one of the two included hospitals the list of daily positives is reviewed by an Infectious Diseases attending to determine whether cases have been tested for CDI and if not if they meet criteria for CDI. Adult patients with FilmArray GI Panel positive for C. difficile on admission to the hospital who lacked dedicated testing for C. difficile were included in the analysis and were stratified as possible, probable and definite cases of missed CDI diagnosis. RESULTS: Among the 144 adult patients with a FilmArray GI Panel test positive for C. difficile within 48 hours of hospital admission, 18 did not have a concurrent dedicated C. difficile testing. Eight patients were categorized as possible cases of missed CDI diagnosis, 5 as probable and 4 as definite, for a total of 17 cases of at least possibly missed CDI diagnosis. One case was considered to represent C. difficile colonization rather than infection for a rate of 6.9% of CDI over-diagnosis based on the FilmArray GI Panel results. Missed CDI diagnoses were associated with a delay in initiation of appropriate therapy, admission to the intensive care unit, hospital re-admission, colorectal surgery and death/discharge to hospice. Five out of 17 cases of missed CDI diagnosis (29.4%) lacked traditional risk factors for CDI. CONCLUSION: In conclusion, the practice of concealing FilmArray GI Panel results for C. difficile may lead to a higher rate of missed CDI diagnosis than over-diagnosis and might need to be re-considered at least in patients with community-onset colitis of unknown etiology on presentation to the hospital. DISCLOSURES: All authors: No reported disclosures.