Accuracy of a Novel 29-Messenger RNA Host-Response Assay for Detecting Bacterial and Viral Infections

A novel 29-messenger RNA blood-based host-response assay (Inflammatix Bacterial Viral Non-Infected version 2 [IMX-BVN-2]), demonstrated high accuracy for detecting the presence of bacterial and viral infections among patients admitted to the emergency department (ED) with either suspected acute infections or sepsis, according to study results published in Critical Care Medicine.

In this prospective, observational study at a quaternary care hospital in Germany, researchers investigated the accuracy of IMX-BVN-2 for predicting the presence of bacterial and viral infections in 312 patients admitted to the ED. The infection status of each patient was adjudicated by 2 attending physicians via chart review. The 2 physicians were blinded to the IMX-BVN-2 results but not to other biomarkers, such as C reactive protein (CRP), procalcitonin (PCT), and leukocyte count. Bacterial and viral infections were classified into consensus adjudication, which included patients with consensus regarding infection status, and forced adjudication, which included those with indeterminate infection status.

To assess the performance of IMX-BVN-2, the researchers calculated the area under the receiver operating characteristic curves (AUROC) for distinguishing bacterial and viral infection and then compared the results with the routine biomarkers (PCT, CRP, and leukocyte count).

Patients included in the analysis were older (median age, 73 years), 24.4% had a quick sequential organ failure assessment score of 2 or more, 27.6% had malignancies, and 20.8% were immunocompromised. In-hospital death occurred in 7.1% of patients, and 18.6% had multi-organ failure within 72 hours of ED admission.

Under consensus adjudication, the IMX-BVN-2 bacterial score showed an AUROC of 0.90 (95% CI, 0.85-0.95). In comparison, the AUROCs for PCT, CRP, and leukocyte count were 0.89 (95% CI, 0.84-0.94), 0.84 (95% CI, 0.77-0.90), and 0.77 (95% CI, 0.69-0.85), respectively. The IMX-BVN-2 viral score showed an AUROC of 0.83 (95% CI, 0.77-0.89), and the AUROCs for the other 3 biomarkers were less than 0.39.

Under forced adjudication, the IMX-BVN-2 bacterial score showed an AUROC of 0.82 (95% CI, 0.77–0.86). In comparison, the AUROCs for PCT, CRP, and leukocyte count were 0.80 (95% CI, 0.75-0.85), 0.79 (95% CI, 0.74-0.85), and 0.69 (95% CI, 0.63-0.76), respectively. The IMX-BVN-2 viral score showed an AUROC of 0.82 (95% CI, 0.76-0.88), and the AUROCs of the other 3 biomarkers were less than 0.40.

Subpopulation analysis among patients with bacterial infections showed that IMX-BVN-2 scores were increased among patients with intra-abdominal or urogenital infections vs those with respiratory infections, and among those with infections due to Gram-negative bacteria vs Gram-positive bacteria.

The limitations of this study included the imperfect adjudicated infection status, and the inability of IMX-BVN-2 to classify patients with both bacterial and viral infections.

The ability of IMX-BVN-2 to identify bacterial and viral infections among patients admitted to the ED was highly accurate.“ An advantage in time and accuracy could improve patient outcomes while upholding antimicrobial stewardship,” concluded the researchers.

Reference

Bauer W, Kappert K, Galtung N, et al. A novel 29-messenger RNA host-response assay from whole blood accurately identifies bacterial and viral infections in patients presenting to the emergency department with suspected infections: a prospective observational study. Crit Care Med. Published online July 19, 2021. doi:10.1097/CCM.0000000000005119