1150. A Novel Host-protein Assay Accurately Distinguishes Bacterial From Viral Upper Respiratory Tract Infections
Session: Poster Abstract Session: Diagnostics: Biomarkers
Friday, October 6, 2017
Room: Poster Hall CD

Background:

Bacterial and viral infections are often clinically indistinguishable, particularly in upper respiratory tract infections (URTI), which leads to antibiotic misuse. A novel assay (ImmunoXpert™) that integrates measurements of three host-response proteins (TRAIL, IP-10, CRP) was recently developed to assist in differentiation between bacterial and viral etiologies. We evaluated the assay performance in URTI patients and compared it with standard laboratory measures.

Methods:

We performed a sub-analysis of 464 patients with clinical suspicion of URTI enrolled in three previously conducted multi-center clinical studies that evaluated the assay performance in patients with acute infections: 'Curiosity' study (NCT01917461), 'Opportunity' study (NCT01931254), and 'Pathfinder' study (NCT01911143). Comparator method was predetermined criteria combined with expert panel adjudication, which was blinded to the test results. Diagnostic performance was evaluated by comparing test and comparator method outcomes.

Results:

A unanimous panel adjudication was attained for 61 bacterial (13%) and 241 viral (52%) patients (162 patients (35%) had an indeterminate diagnosis). The assay distinguished between bacterial and viral infected patients with a sensitivity of 92% (95% CI: 82%- 98%) and specificity of 93% (88%-96%) with 11% equivocal test results. Overall the assay outperformed other routine laboratory tests (FIG 1), including: white blood cell count (WBC; cut-off 15,000 cells/µl, sensitivity 48% (35%-60%), P<10-6; specificity 85% (80%-90%), P<0.05); CRP (cutoff 40 mg/L, sensitivity 82% (72%-92%), P=0.16, specificity 79% (74%-84%), P<10-4); Procalcitonin (PCT; cutoff 0.5 ng/ml, sensitivity 22% (11%-32%), P<10-14, specificity 80% (74%-85%), P<0.001); absolute neutrophil count (ANC; cut-off 10,000 cells /µl,  sensitivity 58% (45%-71%), P<10-4, specificity 94% (91%-97%), P=0.7).

Conclusion:

The novel assay demonstrated superior performance compared to routine laboratory tests (WBC, ANC) and biomarkers (CRP, PCT), in distinguishing bacterial from viral etiologies in patients with URTI. It has the potential to help clinicians avoid missing bacterial infections or prescribing unwarranted antibiotics for viral URTIs.

 

Kfir Oved, PhD1, Eran Eden, PhD1, Chantal Van Houten, MD2, Tanya Gottlieb, PhD1, Roy Navon, MSc1, Asi Cohen, PhD1, Olga Boico, PhD1, Meital Paz, BSc1, Liat Etshtein, MD1, Gali Kronenfeld, M.Sc.1, Tom Friedman, MD1,3, Ellen Bamberger, MD1,4,5, Irina Chistyakov, MD6,7, Israel Potasman, MD, FIDSA8, Michal Stein, MD9, Adi Klein, MD10, Alain Gervaix, MD11, Isaac Srugo, MD6,7 and Louis Bont, MD/PhD2, (1)MeMed Diagnostics, Tirat Carmel, Israel, (2)Division of Paediatric Immunology and Infectious Diseases, University Medical Centre Utrecht, Utrecht, Netherlands, (3)Rambam Health Care Campus, Haifa, Israel, (4)Bnai Zion Medical Center, Haifa, Israel, (5)Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel, (6)Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel, (7)Department of Pediatrics, Bnai-Zion Medical Center, Haifa, Israel, (8)Infectious Diseases, Bnai Zion Medical Center, Haifa, Israel, (9)Infectious Disease Unit, Hillel Yaffe Medical Center, Hadera, Israel, (10)Department of Pediatrics, Hillel Yaffe Medical Center, Hadera, Israel, (11)Pediatric Emergency Medicine Division, University Hospitals of Geneva, Geneva, Switzerland

Disclosures:

K. Oved, MeMed Diagnostics: Board Member , Employee and Shareholder , Salary

E. Eden, MeMed Diagnostics: Board Member , Employee and Shareholder , Salary

C. Van Houten, None

T. Gottlieb, MeMed Diagnostics: Employee , Salary

R. Navon, MeMed Diagnostics: Employee , Salary

A. Cohen, MeMed Diagnostics: Employee , Salary

O. Boico, MeMed Diagnostics: Employee , Salary

M. Paz, MeMed Diagnostics: Employee , Salary

L. Etshtein, MeMed Diagnostics: Employee , Salary

G. Kronenfeld, MeMed Diagnostics: Employee , Salary

T. Friedman, MeMed Diagnostics: Employee , Salary

E. Bamberger, MeMed Diagnostics: Employee , Salary

I. Chistyakov, MeMed Diagnostics: Consultant , Consulting fee

I. Potasman, MeMed Diagnostics: Holding stock options , stock options

M. Stein, None

A. Klein, None

A. Gervaix, None

I. Srugo, None

L. Bont, None

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