Real-World Study Assessing Sensitivity and Clinical Utility of a Host-Protein Test in Adult Emergency Department Patients With Blood Culture Ordered.

Objectives: Difficulty in distinguishing bacterial from viral infections leads to suboptimal patient management. MeMed BV (MMBV) is a Food and Drug Administration-cleared host-protein test with >98% negative predictive value (NPV) for distinguishing bacterial (including coinfection) from viral infections. This study aimed to validate MMBV's sensitivity compared with blood cultures and assess clinical impact over time. Methods: At Maimonides Medical Center emergency department (ED) (March 2022 to March 2024), adults were included if both MMBV and blood cultures were ordered at the physician's discretion. Sensitivity was evaluated against clinically relevant blood cultures. Alignment was defined as not prescribing antibiotics for MMBV viral results (score <35) and prescribing for bacterial (score >65). Outcomes included prescribing alignment, antibiotic prescription, hospital admission, and 7-day ED-return visits. Outcomes were compared across matching time periods: April 2022 to March 2023 (period 1) and April 2023 to March 2024 (period 2). Results: The study included 681 adults (median age, 72 years; 52.9% male), with 58 clinically relevant blood cultures, 29 contaminated cultures, and 594 negative cultures. MMBV attained 96.4% sensitivity (95% CI, 87.0-99.7) and 98.6% NPV (94.5-99.9). Comparing period 1 (n = 353) with period 2 (n = 291), antibiotic prescription among patients with viral MMBV results decreased from 80.7% to 61.4% (P = .017), hospital admissions declined from 77.3% to 61.4% (P = .056), and there was no significant change in return visits. Antibiotic prescription to patients with bacterial MMBV results increased from 93.0% to 98.1% (P = .012) without impacting admission or return visits. Conclusion: MMBV demonstrated high sensitivity. Increased test alignment is associated with reduced antibiotic prescription and hospital admission in viral MMBV cases without compromising safety.