Rapid blood test distinguishes bacterial from viral infections in feverish infants
A new blood test measures CD64 and CD169 proteins on white blood cells to distinguish bacterial from viral infections in feverish infants within 15 to 20 minutes. In a study of 85 babies under 90 days old, it identified all 15 bacterial cases and 44 viral cases. This could reduce unnecessary antibiotics, since only about 15 per cent of febrile babies have serious bacterial infections.
The assay tracks two markers on distinct white blood cell types. CD64 rises on neutrophils during bacterial infection, while CD169 increases on monocytes in viral infection. Comparing both helps classify fever's cause.
In the 85-infant study, all participants were under 90 days and had no prior major health issues. The test matched 15 bacterial, 44 viral, and 26 non-infected cases. Bellini reported these findings in Paris; earlier work had validated the markers in adults.
If validated for routine hospital use, this test could help clinicians avoid giving antibiotics to febrile infants who likely have viral illnesses. Families may face shorter diagnostic uncertainty, while hospitals could use antibiotics more selectively, potentially slowing resistance. The benefit depends on rapid, reliable bedside deployment and confirmatory studies. It may also reassure doctors when deciding whether to admit or discharge very young babies.