# P-829. Words Matter: Impact of Microbiology Laboratory Result Presentation on Antibiotic Stewardship

## TL;DR

This study shows that clearer microbiology lab reports help doctors make better antibiotic decisions, improving patient care.

## Contribution

The study demonstrates that adding detailed interpretative comments to lab results significantly improves clinical decision-making.

## Key findings

- Detailed comments in lab reports increased correct responses for C. difficile and S. pneumoniae.
- Adding guidance to blood culture results boosted correct interpretations from 58% to 92%.
- Providers were more likely to de-escalate antibiotics when given clearer lab information.

## Abstract

Advancements in laboratory diagnostics are continually occurring and accuracy in interpreting results directly affects optimal patient care. In 2019, Wesley Healthcare surveyed providers on their interpretation of common microbiology results. Feedback led to several updates in how common organisms were reported. The purpose of this study was to evaluate whether these changes in reporting positively impacted clinical decisions made from the updated results.Blood cultures positive for S. aureus Pre-InterventionBlood cultures positive for S. aureus Post-Intervention

Blood cultures positive for S. aureus Pre-Intervention

Blood cultures positive for S. aureus Post-Intervention

This quasi-experimental study evaluated the impact of different verbiage on common microbiology results. A survey with six patient cases was sent to providers in 2019 and 2024. Patient cases remained the same in each survey, but utilized the current presentation of microbiology results at the time of the survey. Recipients were asked to make clinical decisions based on the microbiology results presented. The topics included de-escalation of antibiotics based on polymerase chain reaction (PCR) for positive blood cultures (Images 1 and 2), evaluation of C. difficile PCR and enzyme immunoassays, impact of recent immunization on S. pneumoniae urine antigen results, susceptibilities of Group C Streptococcus and H. influenzae (Images 3 and 4), and understanding of minimum inhibitory concentrations (MIC). Chi-squared statistics were used to compare results.H. Influenzae Results (Pre-Intervention)H. Influenzae Results (Post-Intervention)

H. Influenzae Results (Pre-Intervention)

H. Influenzae Results (Post-Intervention)

Several trends were seen in both groups. Questions accompanied by lab results that included detailed comments had the highest percentage of correct responses. This included our C. difficile (Pre: 92%, Post: 98%) and S. pneumoniae urine antigen (Pre: 95%, Post: 94%) results. Culture results without any guidance or adjustment between surveys (Group C Streptococcus, Pre:72%, Post: 81%), had sustained lower rates of correct interpretation and resulted in provider reluctance to de-escalate antibiotics. Culture results which had guidance added between the two time periods had a significant increase in percentage of correct responses. This included blood cultures results by PCR (Pre: 58%, Post: 92%, p= < 0.0001) and H. influenzae (Pre: 86%, Post: 98%, p= < 0.02).

Addition of detailed interpretative comments to microbiology results may lead to improved de-escalation and promote appropriate antibiotic selection.

All Authors: No reported disclosures