{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T19:57:35Z","timestamp":1784750255576,"version":"3.55.0"},"reference-count":23,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2025,4,24]],"date-time":"2025-04-24T00:00:00Z","timestamp":1745452800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"ISCIII","award":["CM23\/00216"],"award-info":[{"award-number":["CM23\/00216"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: Parapneumonic pleural effusion (PPE) secondary to community-acquired pneumonia is the most common cause of pediatric pleural effusion. This study aimed to evaluate the pleural fluid characteristics of pediatric patients with PPE and to compare biomarkers between infants (1\u201312 months) and children (1\u201314 years). Methods: Fifty-four pediatric patients (14 infants and 40 children) with PPE were included. Pleural fluid samples were analyzed for white blood cell (WBC) count, glucose, total protein, lactate dehydrogenase (LDH), adenosine deaminase (ADA), and pH levels. Differences between age groups and correlations between age and pleural fluid biomarkers were assessed. Results: Most pediatric PPE cases exhibited biochemical characteristics consistent with pleural exudate: WBC &gt; 1000 cells\/\u00b5L, total protein &gt; 3 g\/dL, LDH &gt; 200 U\/L. Infants showed a predominance of mononuclear WBC, while children exhibited a predominance of polymorphonuclear WBC. Glucose levels were higher, and total protein levels were lower in infants compared to children. Age was positively correlated with polymorphonuclear WBC percentage (rho = 0.509, p &lt; 0.001) and protein levels (rho = 0.622, p &lt; 0.001), whereas glucose levels were negatively correlated with age (rho = \u22120.274, p = 0.043). Conclusions: Age-specific differences in pleural fluid biomarkers were observed in pediatric patients with PPE, suggesting a more robust and acute inflammatory response in children compared to infants. These findings underscore the importance of considering age-related variations in the inflammatory response when diagnosing and managing PPE in pediatric populations.<\/jats:p>","DOI":"10.3390\/diagnostics15091086","type":"journal-article","created":{"date-parts":[[2025,4,24]],"date-time":"2025-04-24T11:44:52Z","timestamp":1745495092000},"page":"1086","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Pleural Fluid Biomarkers of Pediatric Parapneumonic Effusion"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8851-7551","authenticated-orcid":false,"given":"Jose D.","family":"Santotoribio","sequence":"first","affiliation":[{"name":"Department of Laboratory Medicine, Puerto Real University Hospital, 11510 Cadiz, Spain"},{"name":"Instituto de Investigaci\u00f3n e Innovaci\u00f3n Biom\u00e9dica de C\u00e1diz (INiBICA), 11009 Cadiz, Spain"},{"name":"ExPhy Research Group, Department of Physical Education, Cadiz University, 11519 Cadiz, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0360-5625","authenticated-orcid":false,"given":"David","family":"Nu\u00f1ez-Jurado","sequence":"additional","affiliation":[{"name":"Department of Clinical Biochemistry, Virgen del Roc\u00edo University Hospital, 41013 Seville, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-4557-8625","authenticated-orcid":false,"given":"Jose L.","family":"Rubio-Prieto","sequence":"additional","affiliation":[{"name":"Department of Clinical Biochemistry, Virgen del Roc\u00edo University Hospital, 41013 Seville, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juan M.","family":"Guerrero","sequence":"additional","affiliation":[{"name":"Department of Clinical Biochemistry, Virgen del Roc\u00edo University Hospital, 41013 Seville, Spain"},{"name":"Department of Molecular Biology, Biochemistry and Immunology, Seville University School of Medicine, 41009 Seville, Spain"},{"name":"Neuro-Inmuno-Endocrinolog\u00eda Molecular Group, Instituto de Biomedicina de Sevilla (IBIS), 41013 Seville, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juan","family":"Corral-P\u00e9rez","sequence":"additional","affiliation":[{"name":"Instituto de Investigaci\u00f3n e Innovaci\u00f3n Biom\u00e9dica de C\u00e1diz (INiBICA), 11009 Cadiz, Spain"},{"name":"ExPhy Research Group, Department of Physical Education, Cadiz University, 11519 Cadiz, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7297-6876","authenticated-orcid":false,"given":"Juan J.","family":"Fern\u00e1ndez-Alba","sequence":"additional","affiliation":[{"name":"Instituto de Investigaci\u00f3n e Innovaci\u00f3n Biom\u00e9dica de C\u00e1diz (INiBICA), 11009 Cadiz, Spain"},{"name":"Department of Obstetrics and Gynecology, Hospital Universitario de Puerto Real, 11510 Puerto Real, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,4,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1097\/01.inf.0000069764.41163.8f","article-title":"Incidence and Etiologies of Complicated Parapneumonic Effusions in Children, 1996 to 2001","volume":"22","author":"Buckingham","year":"2003","journal-title":"Pediatr. 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