A New Rapid Way to Determine Viral vs Bacterial?
October 16, 2024
Written by Catherine Burger
Spoon Feed
This prospective study of a new proprietary rapid host-protein test, MeMed BV (MMBV), shows promising results for differentiating viral vs bacterial causes of fever. However, the gold standard for comparison was similar to current common practice, making it difficult to measure the added value of MMBV over usual care.
Biomarker potpourri…
This was a prospective, multicenter study of 476 adults and children presenting with fever to 9 emergency departments and 3 urgent cares in the US and Israel, where authors looked at the performance of a new rapid host-protein test, MMBV, and its ability to determine viral vs bacterial etiology of febrile patients. MMBV uses three inflammatory markers (CRP, tumor necrosis factor-related apoptosis-inducing ligand [TRAIL], and interferon gamma-inducible protein-10 [IP-10]) to provide a score of 0 (likely viral etiology) to 100 (likely bacterial etiology). They compared preplanned specific MMBV cutoffs of <35 (viral etiology) and >65 (bacterial etiology), to expert opinion on the likely cause of fever as either viral, bacterial, or indeterminant. Expert opinion was based on chart review, follow up patient phone calls, as well as CBC, PCT, and RPP results. Treating providers and experts were blinded to MMBV results. 3 experts evaluated each patient’s chart and agreed on a fever etiology as either bacterial, viral, or indeterminant 92% of the time. Suspected viral and bacterial co-infection cases were analyzed under bacterial etiology.
MMBV sensitivity was 90.0% (95%CI 80.3-99.7), specificity 92.8% (90.0-95.5), NPV 98.8% (96.8-99.6) for bacterial infection. These calculations excluded all equivocal MMBV results (values >35 and <65, n = 46) and cases where the experts were uncertain of the fever etiology (n = 60). The authors also report a ROC-AUC of 0.95 (0.90-0.99), compared to PCT 0.70 (0.61-0.79), using a cut off value of 0.25 ng/mL.
How will this change my practice?
It’s hard to define a gold standard for something as complex and elusive as fever etiology. When EPs face a difficult case, we often use the patient’s H&P and lab values to help us decide on a treatment pathway. Because the gold standard in this study is very similar to usual care (clinical evaluation supplemented by labs, such as CBC, PCT and RPP), it is hard for me to know how much the MMBV value adds to my current treatment decisions. Additionally, 18.9% of the cases fell into an indeterminate range, either for the biomarker or expert opinion, and were excluded from the statistical analysis.
This study foreshadows the potential advantage of combining multiple biomarkers into one useful predictive score, and I look forward to continued research in this area.
Editor’s note: Thanks to a JournalFeed EM reader who sent me this paper after his hospitalists referred to it a few times. He thought we should cover it. Agree! ~Clay Smith
Source
A rapid host-protein test for differentiating bacterial from viral infection: Apollo diagnostic accuracy study. J Am Coll Emerg Physicians Open. 2024 May 8;5(3):e13167. doi: 10.1002/emp2.13167. PMID: 38721037; PMCID: PMC11077430.