Pentraxin 3 (Ptx3) is an acute-phase protein that specifically targets fungal galactosaminogalactan and has been proposed as a promising biomarker for invasive fungal infections. However, its stability in clinical samples over time has not yet been established. This study aimed to evaluate the stability of Ptx3 in serum and bronchoalveolar lavage fluid (BALF) samples during mid- and long-term storage. A total of 44 serum and 52 BALF samples were examined or re-examined for Ptx3 concentrations using enzyme immunoassay in pooled and individual sample formats. Samples were stored at -80°C, -20°C, and +37°C for periods ranging from 0 to 56 months. Statistical analyses included a paired two-sample Wilcoxon signed-rank test, analysis of variance, Bonferroni test, and linear regression analysis. Ptx3 remained highly stable in serum and BALF samples for up to 8 months at -20°C, with variations ranging from -1.8% to +2.8%. Long-term stability was observed at -80°C for 48 months, followed by a slow decline in Ptx3 levels. In contrast, storage at +37°C resulted in rapid degradation, with a 36.5%-60.7% increase or a 92.9%-97% decrease in Ptx3 levels in serum and BALF, respectively. These findings confirm that Ptx3 is a stable and reliable biomarker for invasive fungal infections when appropriate storage conditions are maintained.

Pentraxin 3 is a promising marker of fungal infections. This study shows it remains stable in body fluids samples for months when properly frozen, but breaks down quickly when stored at warmer temperatures, supporting its use in diagnostics under standard storage conditions.

Biomedicine Research Centre of the Slovak Academy of Sciences Institute of Virology Bratislava Slovakia

Department of Analytical Chemistry Faculty of Science Palacký University Olomouc Czech Republic

Department of Bacteriology and Mycology National Reference Laboratory for Mycological Diagnostics Public Health Institute in Ostrava Ostrava Czech Republic

Department of Immunology Faculty of Medicine and Dentistry Palacký University and University Hospital Olomouc Czech Republic

Institute of Laboratory Medicine Faculty of Medicine University of Ostrava Ostrava Czech Republic

Institute of Microbiology of the Czech Academy of Sciences Prague Czech Republic

Institute of Molecular and Clinical Pathology and Medical Genetics Faculty of Medicine University of Ostrava Ostrava Czech Republic

Institute of Molecular and Clinical Pathology and Medical Genetics University Hospital Ostrava Ostrava Czech Republic

See more in PubMed

Zhang  Y, Li  X, Zhang  X, Wang  T, Zhang  X. Progress in the study of pentraxin-3(PTX-3) as a biomarker for sepsis. Front Med. 2024; 11: 1398024. PubMed PMC

Daigo  K, Inforzato  A, Barajon  I, et al.  Pentraxins in the activation and regulation of innate immunity. Immunol Rev. 2016; 274(1): 202–217. PubMed PMC

Dellière  S, Chauvin  C, Wong  SSW, et al.  Interplay between host humoral pattern recognition molecules controls undue immune responses against PubMed PMC

Kang  Y, Yu  Y, Lu  L. The role of Pentraxin 3 in aspergillosis: reality and prospects. Mycobiology. 2020; 48(1): 1–8. PubMed PMC

Dobiáš  R, Jaworská  P, Skopelidou  V, et al.  Distinguishing invasive from chronic pulmonary infections: host pentraxin 3 and fungal siderophores in bronchoalveolar lavage fluids. J Fungi. 2022; 8(11): 1194. PubMed PMC

Li  H, Liu  L, Zhou  W, et al.  Pentraxin 3 in bronchoalveolar lavage fluid and plasma in non-neutropenic patients with pulmonary aspergillosis. Clin Microbiol Infect. 2019; 25(4): 504–510. PubMed

Chen  H, Li  T, Yan  S, et al.  Pentraxin-3 is a strong biomarker of sepsis severity identification and predictor of 90-day mortality in intensive care units via sepsis 3.0 definitions. Diagnostics. 2021; 11(10): 1906. PubMed PMC

Wang  G, Jiang  C, Fang  J, Li  Z, Cai  H. Pentraxin-3 as a predictive marker of mortality in sepsis: an updated systematic review and meta-analysis. Crit Care. 2022; 26(1): 167. PubMed PMC

de Bruin  S, Bos  LD, van Roon  MA, et al.  Clinical features and prognostic factors in COVID-19: a prospective cohort study. EBioMed. 2021; 67: 103378. PubMed PMC

Wang  Y, Chen  W, Ding  S, Wang  W, Wang  C. Pentraxins in invertebrates and vertebrates: from structure, function and evolution to clinical applications. Dev Comp Immunol. 2023; 149: 105064. PubMed

Dobiáš  R, Stevens  DA, Havlíček  V. Current and future pathways in PubMed PMC

Milas  GP, Issaris  V, Niotis  G. Pentraxin-3 and neonatal sepsis: a systematic review and meta-analysis. J Matern Fetal Neonatal Med. 2023; 36(1): 2205986. PubMed

Ke  Y, Wu  K, Shen  C, et al.  Clinical utility of circulating Pentraxin 3 as a prognostic biomarker in coronavirus disease 2019: a systematic review and meta-analysis. Infect Dis Ther. 2023; 12(1): 67–80. PubMed PMC

Janssen  L, Sobott  F, De Deyn  PP, et al.  Signal loss due to oligomerization in ELISA analysis of amyloid-beta can be recovered by a novel sample pre-treatment method. MethodsX. 2015; 2(2):112–123. PubMed PMC

Ceaglio  N, Etcheverrigaray  M, Kratje  R, et al.  Influence of carbohydrates on the stability and structure of a hyperglycosylated human interferon alpha mutein. Biochimie. 2010; 92(8): 971–978. PubMed

Pikal-Cleland  KA, Rodríguez-Hornedo  N, Amidon  GL, et al.  Protein denaturation during freezing and thawing in phosphate buffer systems: monomeric and tetrameric beta-galactosidase. Arch Biochem Biophys. 2000; 384(2): 398–406. PubMed

Doumatey  AP, Zhou  J, Adeyemo  A, et al.  High sensitivity C-reactive protein (Hs-CRP) remains highly stable in long-term archived human serum. Clin Biochem, 2014; 47(4–5):315–318. PubMed PMC