A-241 Verification and Validation Study for a Host Response Assay Based on TRAIL, IP-10, and CRP: Application to Pediatric Emergency Department
Authors: Styer A M , Anderson N , Alander S , Gowtham S , Jeffreys K , Vodzak J , Hirschhorn J W , Wolk D M 
Published: October 2024

Abstract

Background
Acute febrile illnesses (AFIs) represent a significant disease burden globally; however, the lack of reliable, rapid point-of-care testing makes diagnosis difficult. A simple tool for distinguishing bacterial versus non-bacterial infections would radically improve patient management and reduce indiscriminate antibiotic use. MeMed BV® (MMBV) is a blood test to reliably differentiate between viral and bacterial infections. Three host proteins (TRAIL, IP-10, and CRP) are measured quantitatively and a combinational score (0-100) is computed that indicates the likelihood of bacterial infection (or co-infection) versus viral infection (BV Score). MMBV time to result is 15 min on the MeMed Key® analyzer that conducts chemiluminescence-based immunoassays to measure protein concentrations and calculates the test score, using 100 µL of serum.

Methods
The verification study design was a comparison of known results to on-site testing for contrived samples. The validation study design was a prospective, single-center, observational, blinded diagnostic accuracy study conducted between 8/3/22 to 5/30/23. The population was pediatric patients with suspected serious infections presenting to Geisinger’s quaternary care Pediatric Emergency Dept. in Danville, PA. The comparator was a clinical chart review and adjudication of over 60 clinical and laboratory variables related to systemic infections. The data review team consisted of one pediatric emergency department physician, one pediatric infectious disease physician, and one microbiology laboratory director. If clinical decisions differed among the three, the team adjudicated with a full chart review including knowledge of the eventual outcome, which served as the final reference standard result. The study aims were to assess the analytical and clinical accuracy of MMBV testing and to assess the test’s potential impact to further inform the provider’s decision to admit or discharge the patient.

Results
Of 60 contrived samples there was three failed tests (5% failure rate) and 2 discordant results. Analytical accuracy was 55/57 (96.5%) for 28 bacterial, 26 viral, and 1 equivocal control. Of 50 pediatric patients recruited, 8 were excluded because they were trauma patients. Among 42 patients tested, 22/42 (52.4%) were interpreted as bacterial or co-infection, 16/42 (38.1%) as viral or non-infectious, and 4/42 (9.5%) as equivocal. For 37/38 (97.3%) of patients with bacterial/viral MMBV results, the result was concordant with expert adjudication. Of the 42 patients for which potential utility was assessed, all results were in alignment with the clinical decisions made for admission or discharge.

Conclusions
MMBV performed accurately in pediatric ED patients with symptoms of severe infection, both clinically and analytically. A larger sample size will be tested to assess the utility in ED admission and discharge decisions and antimicrobial stewardship. The prevalence of viral and bacterial or coinfection cases within the sample population is representative of the pediatric population samples.