Evaporation of serum after long-term biobank storage: A chemical analysis of maternal serum from a large Danish pregnancy screening registry.

Autor: Uldbjerg CS; Department of Growth and Reproduction, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.; International Centre for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Denmark., Sørensen KM; Danish National Biobank, Statens Serum Institut, Denmark., Lindh CH; Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden., Rantakokko P; Department of Health Security, Finnish Institute for Health and Welfare, Kuopio, Finland., Hauser R; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America., Juul A; Department of Growth and Reproduction, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.; International Centre for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Denmark.; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark., Andersson AM; Department of Growth and Reproduction, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.; International Centre for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Denmark., Bräuner EV; Department of Growth and Reproduction, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.; International Centre for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, University of Copenhagen, Denmark.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2023 Oct 26; Vol. 18 (10), pp. e0293527. Date of Electronic Publication: 2023 Oct 26 (Print Publication: 2023).
DOI: 10.1371/journal.pone.0293527
Abstrakt: Background: Relying on freezer stored biospecimens is preferred in epidemiolocal studies exploring environmental pregnancy exposures and later offspring health. Storage duration may increase the pre-analytical variability, potentially adding measurement uncertainty. We investigated evaporation of maternal serum after long-term biobank storage using ions (sodium, Na+; chloride, Cl-) recognized for stability and relatively narrow normal biological reference ranges in human serum.
Methods: A chemical analysis study of 275 biobanked second trimester maternal serum from a large Danish pregnancy screening registry. Serum samples were collected between 1985-1995 and stored at -20°C. Ion concentrations were quantified with indirect potentiometry using a Roche Cobas 6000 analyzer and compared according to storage time and normal biological ranges in second trimester. Ion concentrations were also compared with normal biological variation assessed by baseline Na+ and Cl- serum concentrations from a separate cohort of 24,199 non-pregnant women measured before freezing with the same instrument.
Results: The overall mean ion concentrations in biobanked serum were 147.5 mmol/L for Na+ and 109.7 for Cl-. No marked linear storage effects were observed according to storage time. Ion concentrations were consistently high across sampling years, especially for specific sampling years, and a relatively large proportion were outside respective normal ranges in second trimester: 38.9% for Na+ and 43.6% for Cl-. Some variation in concentrations was also evident in baseline serum used as quality controls.
Conclusions: Elevated ion concentrations suggest evaporation, but independent of storage duration in the present study (27-37 years). Any evaporation may have occurred prior to freezer storage or during the first 27 years. Other pre-analytical factors such as low serum volume have likely influenced the concentrations, particularly given the high within year variability. Overall, we consider the biobanked serum samples internally comparable to enable their use in epidemiological studies.
Competing Interests: The authors have declared that no competing interest exist.
(Copyright: © 2023 Uldbjerg et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
Databáze: MEDLINE
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