{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T20:44:50Z","timestamp":1792788290833,"version":"4.5.0"},"reference-count":31,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T00:00:00Z","timestamp":1780012800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T00:00:00Z","timestamp":1780012800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"name":"Gentian AS"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["ICMx"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Reliably distinguishing infection from sterile inflammation is a major clinical challenge. Uncertainty can lead to unnecessary courses of antibiotics, fueling antimicrobial resistance and adverse effects. Calprotectin, a biomarker released by activated immune cells, may inform decision-making.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This prospective, observational, single-centre study recruited patients with suspected infection who provided blood samples on enrolment from the Emergency Department (ED) and Intensive Care Unit (ICU) of a central London university hospital. A separate longitudinal study with five days\u2019 blood sampling was performed in patients undergoing elective major non-cardiac surgery, in whom infection was adjudicated according to the Standardised Endpoints in Perioperative Medicine (StEP) initiative. Diagnostic adjudication was performed blinded to calprotectin. The primary outcome was the ability of calprotectin to diagnose infection. Secondary outcomes included a comparison to C-reactive protein (CRP).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>427 patients were included, of whom 186 (44%) were female. Of 245 ED patients, 71 (29%) had active cancer and 56 (23%) were on immunosuppressants. The median calprotectin level in the no-infection group was 1.97\u00a0mg\/L (IQR 1.02\u20133.39), compared to 2.76 (IQR 1.65\u20135.08) mg\/L in low-probability infection, 2.63\u00a0mg\/L (IQR 1.83\u20135.23) in high-probability infection, and 2.64\u00a0mg\/L (IQR 1.49\u20134.45) in patients with confirmed infection. Ordinal regression analysis found no meaningful association between calprotectin levels and infection, or bacterial infection. Logistic regression showed an unadjusted AUC of 0.53 (95%-CI 0.45\u20130.62) for calprotectin and a binary outcome of infection compared to an AUC of 0.63 (95%-CI 0.55\u20130.71) for CRP. Similar results were seen in a sensitivity analysis excluding patients with cancer or immunosuppression. In 98 ICU patients, neither calprotectin nor CRP showed a meaningful association with an adjudicated diagnosis of infection or ICU death. In the peri-operative cohort, calprotectin levels remained elevated over 5\u00a0days, but with no difference between patients developing or not developing infection.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Calprotectin showed only limited ability to differentiate infection from inflammation across ED, ICU, and elective surgery patients. Excluding patients with cancer or immunosuppression did not alter the overall findings.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s40635-026-00923-3","type":"journal-article","created":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T02:40:43Z","timestamp":1780022443000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Evaluation of plasma calprotectin as a marker for infection in various clinical settings: a prospective observational study"],"prefix":"10.1186","volume":"14","author":[{"given":"Tobias","family":"Zimmermann","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Timothy Arthur Chandos","family":"Snow","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pedro","family":"Lopez-Ayala","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ahmed","family":"Al-Hindawi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Samer","family":"Elkhodair","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nishkantha","family":"Arulkumaran","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Siegemund","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1042-6350","authenticated-orcid":false,"given":"Mervyn","family":"Singer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Brealey","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,5,29]]},"reference":[{"key":"923_CR1","doi-asserted-by":"publisher","first-page":"200","DOI":"10.1016\/S0140-6736(19)32989-7","volume":"395","author":"KE Rudd","year":"2020","unstructured":"Rudd KE, Johnson SC, Agesa KM et al (2020) Global, regional, and national sepsis incidence and mortality, 1990\u20132017: analysis for the Global Burden of Disease Study. 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Written informed patient or consultee consent\/agreement was obtained from all patients.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"MSin reports research grants and\/or personal fees and\/or donations to the Departmental Research Fund over the last 36\u00a0months for advisory board\/ consultancy\/educational videos\/lecturing from AOP, Aptarion, Bayer, Biomerieux. Biotest, deePull, Deltex Medical, DSTL, Gentian Diagnostics, Matisse, Pfizer, Radiometer, Roche Diagnostics, Safeguard Biosystems, Sanofi, Volition. MS is the Sepsis Topic Advisor to NICE and sits on the Council of the International Sepsis Forum. DB is on the trial steering committee for Synairgen, and reports research grants and\/or personal fees for lecturing from Biomerieux and Abionic. PLA reports research grants from the Swiss Heart Foundation (FF20079, FF21103 and FF24149) and speaker\u2019s honoraria from Quidel, Roche Diagnostics and Polymedco in the last 36\u00a0months, all outside the submitted work. All other authors declare no conflicts of interest relevant to this article.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"64"}}