Authors: Nacke N, et al.
A&A Practice. 2025;19(7):e02004.
This case report investigates the utility of the Intensive Care Infection Score (ICIS) as a novel decision-support tool in antimicrobial stewardship (AMS). ICIS measures early innate immune response to infection, using hematologic markers beyond traditional indicators like CRP, procalcitonin (PCT), and WBC counts, which often reflect inflammation rather than infection specifically.
In three critically ill ICU patients:
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ICIS identified ineffective antibiotic therapy before clinical signs worsened.
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ICIS values stayed elevated despite other markers declining, prompting earlier escalation of antibiotics.
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In a patient with post-op fever and elevated CRP/PCT, declining ICIS supported a noninfectious diagnosis, avoiding unnecessary antibiotics.
These cases demonstrate how ICIS may:
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Reduce antibiotic overuse
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Detect treatment failure earlier
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Improve diagnostic confidence in distinguishing infection from sterile inflammation
The report suggests that ICIS could be a valuable addition to ICU AMS protocols, although broader prospective studies are needed to validate its role.
References:
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Nacke N, Rübsam ML, Fischer D, Hönemann C. Exploring the Potential of the Intensive Care Infection Score in Antimicrobial Stewardship: A Case Report. A&A Practice. 2025;19(7):e02004. https://doi.org/10.1213/XAA.0000000000002004
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Nierhaus A, et al. Use of a weighted, automated analysis of the differential blood count to differentiate sepsis from non-infectious systemic inflammation: The Intensive Care Infection Score (ICIS). Inflamm Allergy Drug Targets. 2012;11:109–115. https://pubmed.ncbi.nlm.nih.gov/22616850/
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Weimann K, et al. Intensive Care Infection Score—A new approach to distinguish between infectious and noninfectious processes in intensive care and medicosurgical patients. J Int Med Res. 2015;43:435–451. https://doi.org/10.1177/0300060514562356
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van der Geest PJ, et al. The intensive care infection score—A novel marker for the prediction of infection and its severity. Crit Care. 2016;20:180. https://doi.org/10.1186/s13054-016-1346-2
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WHO. Antimicrobial resistance. https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance
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