# Rapid blood test detects infant infection type in 15 minutes Protein-based test reduces unnecessary antibiotic use in febrile infants - **Source:** [New Scientist](https://www.newscientist.com/) - **Published:** 2026-09-26 - **Original article:** - **On Brifing:** https://brifing.si/s/486c07ce-8a9d-4c50-a526-23e4c9031b9c ## Critical diagnostic gap Current infection tests take hours, forcing doctors to prescribe antibiotics preemptively to febrile infants despite only 15% having serious bacterial infections. This contributes to antibiotic resistance. The new test analyzes neutrophil CD64 and monocyte CD169 protein levels, biomarkers that differentiate bacterial from viral infections. Previous adult studies showed 100% accuracy in identifying infection types. ## Protein biomarkers validated CD64 increases during bacterial infections on neutrophils, while CD169 rises during viral infections on monocytes. The test correctly identified all 15 bacterial cases, 44 viral cases, and 26 non-infected cases in the 85-infant study. This builds on 2021 research proving these markers' reliability in adults. The technology was developed over a decade by Beckman Coulter researchers. ## Clinical impact potential The 15-20 minute lab result timeframe could transform emergency pediatric care. During a dengue outbreak in Martinique, the test revealed bacterial leptospirosis cases mistaken for viral infections. Researchers are developing a benchtop version for hospital use. A 300-500 infant multicenter trial is planned to validate clinical implementation for this high-risk population. ## Immune system considerations Validating the test for infants required special consideration due to their developing immune systems. Some researchers initially doubted whether CD64/CD169 markers would be reliable in neonates. The successful detection in the 85-infant study confirms these proteins are measurable biomarkers even in immature immune responses. ## Technical implementation The test requires analyzing protein levels in two white blood cell types: neutrophils for CD64 (bacterial indicator) and monocytes for CD169 (viral indicator). Current lab processing takes 15-20 minutes, with efforts underway to develop point-of-care hospital equipment. The finger-prick blood sample method has been approved for research use while awaiting clinical validation. ## Public health implications Unnecessary antibiotic use in pediatrics contributes significantly to antimicrobial resistance. This test could reduce inappropriate prescriptions while ensuring bacterial infections receive prompt treatment. The technology represents a major advance in precision medicine for neonatal care, where rapid diagnosis is critical but challenging. ## Research validation path After demonstrating efficacy in adults (2021) and children, the infant study marks the third validation phase. Researchers presented results at the European Emergency Medicine Congress. Next steps include multicenter trials and regulatory approval for clinical use. Parallel development of rapid analysis equipment aims to make the test practical for emergency settings. ## Future diagnostic standard This protein-based approach could become the gold standard for pediatric infection diagnosis. Its rapid turnaround and high accuracy address critical gaps in neonatal care. As antibiotic resistance grows globally, such precision diagnostics will become increasingly vital in both developed and developing healthcare systems. ## Sources covering this story - https://www.newscientist.com/article/2590894-blood-test-could-gauge-if-a-baby-has-a-dangerous-infection-in-15-minutes/?utm_campaign=RSS|NSNS&utm_content=home&utm_medium=RSS&utm_source=NSNS — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._