{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T18:31:14Z","timestamp":1784140274323,"version":"3.55.0"},"reference-count":33,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T00:00:00Z","timestamp":1779926400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>We aimed to characterize age-stratified C-reactive protein (CRP) patterns across respiratory virus infections, assess age-related CRP shifts in virus-not-detected-by-PCR episodes, and evaluate the independent associations of age and virus type with CRP levels. We retrospectively analyzed 19,002 test-level episodes with paired respiratory PCR and serum CRP results from a single tertiary-care center between 2008 and 2024. Episodes were classified as virus-not-detected-by-PCR or virus-positive according to multiplex PCR results; the former was not considered a healthy control and may include off-panel infections, bacterial\/mixed infections, false-negative results, or non-infectious inflammation. Descriptive analyses and multivariable linear regression of log-transformed CRP were used to assess adjusted associations. Median CRP increased with age in both virus-positive and virus-not-detected-by-PCR episodes, rising from 0.38 to 7.42 mg\/dL across age groups in the latter. Age showed the strongest association with CRP. Adenovirus showed a positive adjusted association, whereas influenza A\/B, respiratory syncytial virus A\/B, and parainfluenza virus types 1 and 3 showed selective negative associations. Overall, CRP variation was more strongly associated with age-related clinical background than with virus type, although selective virus-associated differences were observed, supporting the interpretation of CRP as a non-specific, composite host-response indicator within broader clinical contexts.<\/jats:p>","DOI":"10.3390\/pathogens15060583","type":"journal-article","created":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T02:37:26Z","timestamp":1780454246000},"page":"583","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Age-Structured Clinical Background Is More Strongly Associated with C-Reactive Protein Levels than Individual Respiratory Viruses During Respiratory Virus Testing"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-0934-8445","authenticated-orcid":false,"given":"Sung Hun","family":"Jang","sequence":"first","affiliation":[{"name":"Department of Medical Laser, Graduate School of Medicine, Dankook University, Cheonan-si 31116, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9785-6440","authenticated-orcid":false,"given":"Bo Kyeung","family":"Jung","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine, College of Medicine, Dankook University, Cheonan-si 31116, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8981-5705","authenticated-orcid":false,"given":"Jae-Sik","family":"Jeon","sequence":"additional","affiliation":[{"name":"Department of Biomedical Laboratory Science, College of Health Sciences, Dankook University, Cheonan-si 31116, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-7003-8422","authenticated-orcid":false,"given":"Jeong Su","family":"Han","sequence":"additional","affiliation":[{"name":"Department of Biomedical Laboratory Science, College of Health Sciences, Dankook University, Cheonan-si 31116, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1534-563X","authenticated-orcid":false,"given":"Jae Kyung","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Biomedical Laboratory Science, College of Health Sciences, Dankook University, Cheonan-si 31116, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Kozinska, A., Wegrzynska, K., Komiazyk, M., Walory, J., Wasko, I., and Baraniak, A. 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