Clinical Science Behind FebriDx®

How FebriDx Works

FebriDx uses a proprietary combination of two host immune response biomarkers — CRP and MxA — to aid clinicians in distinguishing bacterial infection from non-bacterial etiology at the point of care.

CRP is an acute-phase inflammatory protein that rises in response to infection and systemic inflammation. It elevates rapidly within hours of infection and reflects the severity of the inflammatory response, but alone remains non-specific for bacterial infection at lower thresholds.

MxA is an innate immune biomarker that elevates specifically in response to acute viral infection. It is not elevated in bacterial infections and demonstrates rapid induction with a prolonged half-life, making it a reliable indicator of viral immune activation.

Individually, CRP and MxA are insufficient to differentiate bacterial from non-bacterial illness.
Together, they provide the clinical sensitivity and specificity needed to support respiratory decision-making.

By combining a marker of systemic inflammation (CRP) with a virus-specific immune marker (MxA), FebriDx delivers actionable insight into the underlying immune response driving acute respiratory illness.

Sample: Fingerstick capillary whole blood
Time to result: ~10–15 minutes
Equipment: No analyzer or external instrumentation
Result format: Simple visual readout
Training: Minimal staff training required
Maintenance: No calibration or ongoing maintenance
Patient Satisfaction: Objective results support clearer conversations when antibiotics are not indicated.

Negative predictive value reflects the likelihood that a patient truly does not have a bacterial infection when the test result is negative. In practical terms, a high NPV helps clinicians.

FebriDx results should always be interpreted in the context of clinical signs, symptoms, and patient history.

A prospective, multi-centre US clinical trial to determine accuracy of FebriDx point-of-care testing for acute upper respiratory infections with and without a confirmed fever

Outpatient Antibiotic Stewardship: A Growing Frontier—Combining Myxovirus Resistance Protein A With Other Biomarkers to Improve Antibiotic Use

FebriDx for C-reactive protein and myxovirus resistance protein A testing

Utility of the FebriDx point-of-care assay in supporting a triage algorithm for medical admissions with possible COVID-19: an observational cohort study

Diagnostic Accuracy of FebriDx: A Rapid Test to Detect Immune Responses to Viral and Bacterial Upper Respiratory Infections

FebriDx for rapid screening of patients with suspected COVID-19 upon hospital admission: systematic literature review and meta-analysis

FebriDx host response point-of-care testing improves patient triage for coronavirus disease 2019 (COVID-19) in the emergency department

Use of the FebriDx® host-response point-of-care test may reduce antibiotic use for respiratory tract

Performance of the FebriDx Rapid Point-of-Care Test for Differentiating Bacterial and Viral Respiratory Tract Infections in Patients with a Suspected Respiratory Tract Infection in the Emergency Department

FebriDx®: A Rapid Diagnostic Test for Differentiating Bacterial and Viral Aetiologies in Acute Respiratory Infections

Emergency Department point-of-care antiviral host response testing is accurate during periods of multiple respiratory virus co-circulation

Diagnostic Accuracy of a Bacterial and Viral Biomarker Point-of-Care Test in the Outpatient Setting

Application of a simple point-of-care test to reduce UK healthcare costs and adverse events in outpatient acute respiratory infections

How To Use

An all-in-one test device

FebriDx instructions for use

Clinical Science Behind FebriDx®

How FebriDx Works

CRP (C-Reactive Protein)

MxA (Myxovirus Resistance Protein A)