{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T17:01:11Z","timestamp":1786122071313,"version":"build-2736575974"},"reference-count":19,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T00:00:00Z","timestamp":1786060800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Clin. Med.","JCM"],"abstract":"<jats:p>Background\/Objectives: Elevated Procalcitonin (PCT) levels are frequently encountered in clinical practice but may occur in both infectious and non-infectious conditions, making their interpretation challenging. This study evaluated the diagnostic performance of PCT, CRP, and lactate for differentiating sepsis, infectious conditions, and non-infectious conditions in patients with elevated baseline PCT levels. Methods: In this single-center retrospective observational study, 1072 adults presenting to the ED between June and December 2024 with serum PCT \u2265 0.51 ng\/mL were included. Patients were classified into sepsis (n = 272), infection (n = 618), and non-infection (n = 182) groups according to the Sepsis-3 criteria and comprehensive clinical adjudication. ROC analyses and DeLong tests were performed to evaluate biomarker performance. Results: For identifying sepsis, PCT demonstrated better discriminatory performance (AUC 0.683) than CRP (AUC 0.619) and lactate (AUC 0.620), with significant differences between PCT and both CRP (p = 0.009) and lactate (p = 0.018). The optimal PCT cut-off was 2.35 ng\/mL (sensitivity 65.8%, specificity 59.5%). For differentiating infectious from non-infectious conditions, CRP showed modest discrimination (AUC 0.640), whereas PCT (AUC 0.581) and lactate (AUC 0.439) performed poorly. Lactate showed the highest prognostic performance for in-hospital mortality (AUC 0.598), although overall prognostic accuracy remained limited. Conclusions: In ED patients with elevated baseline PCT levels, PCT showed better discrimination for sepsis than CRP and lactate, whereas CRP performed modestly in differentiating infectious from non-infectious conditions. None of the biomarkers demonstrated sufficient accuracy for standalone clinical use, supporting their role as complementary tools alongside comprehensive clinical assessment and the Sepsis-3 criteria.<\/jats:p>","DOI":"10.3390\/jcm15166132","type":"journal-article","created":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T08:01:36Z","timestamp":1786089696000},"page":"6132","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Differentiating Sepsis from Infectious and Non-Infectious Conditions in Patients with Elevated Procalcitonin Levels: Performance of Procalcitonin, CRP, and Lactate"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9108-4769","authenticated-orcid":false,"given":"Kamil","family":"Deveci","sequence":"first","affiliation":[{"name":"Department of Intensive Care, Kayseri City Education and Research Hospital, 38080 Kayseri, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Necmi","family":"Baykan","sequence":"additional","affiliation":[{"name":"Department of Emergency, Kayseri City Education and Research Hospital, 38080 Kayseri, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-4421-5791","authenticated-orcid":false,"given":"Fatma","family":"Han\u00e7er \u00c7elik","sequence":"additional","affiliation":[{"name":"Department of Emergency, Gaziantep City Education and Research Hospital, 27470 Gaziantep, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fatma","family":"\u00dcnl\u00fc","sequence":"additional","affiliation":[{"name":"Department of Emergency, Kayseri City Education and Research Hospital, 38080 Kayseri, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2712-9694","authenticated-orcid":false,"given":"Esma Ery\u0131lmaz","family":"Eren","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease and Clinical Microbiology, Kayseri City Education and Research Hospital, University of Health Sciences, 38080 Kayseri, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2754-7594","authenticated-orcid":false,"given":"Davut","family":"Eren","sequence":"additional","affiliation":[{"name":"Department of Nephrology, Kayseri City Education and Research Hospital, 38080 Kayseri, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2494-9152","authenticated-orcid":false,"given":"Maruf","family":"Boran","sequence":"additional","affiliation":[{"name":"Department of Intensive Care, Kayseri City Education and Research Hospital, 38080 Kayseri, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u00d6mer","family":"Salt","sequence":"additional","affiliation":[{"name":"Department of Emergency, Kayseri City Education and Research Hospital, 38080 Kayseri, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1086\/421997","article-title":"Serum Procalcitonin and C-reactive protein levels as markers of bacterial infection: A systematic review and meta-analysis","volume":"39","author":"Simon","year":"2004","journal-title":"Clin. 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PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0181704"}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/16\/6132\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T08:24:59Z","timestamp":1786091099000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/16\/6132"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,7]]},"references-count":19,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["jcm15166132"],"URL":"https:\/\/doi.org\/10.3390\/jcm15166132","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,7]]}}}