Effects of Long-Term Storage Time and Original Sampling Month on Biobank Plasma Protein Concentrations.
The quality of clinical biobank samples is crucial to their value for life sciences research. A number of factors related to the collection and storage of samples may affect the biomolecular composition. We have studied the effect of long-time freezer storage, chronological age at sampling, season and month of the year and on the abundance levels of 108 proteins in 380 plasma samples collected from 106 Swedish women. Storage time affected 18 proteins and explained 4.8-34.9% of the observed variance. Chronological age at sample collection after adjustment for storage-time affected 70 proteins and explained 1.1-33.5% of the variance. Seasonal variation had an effect on 15 proteins and month (number of sun hours) affected 36 proteins and explained up to 4.5% of the variance after adjustment for storage-time and age. The results show that freezer storage time and collection date (month and season) exerted similar effect sizes as age on the protein abundance levels. This implies that information on the sample handling history, in particular storage time, should be regarded as equally prominent covariates as age or gender and need to be included in epidemiological studies involving protein levels.
Department of Immunology, Genetics, and Pathology, Biomedical Center, SciLifeLab Uppsala, Uppsala University, SE 75108 Uppsala, Sweden. Electronic address: stefan.enroth@igp.uu.se.
Stefan
S
Enroth
Department of Biobank Research, Umeå University, SE 90187 Umeå, Sweden.
Göran
G
Hallmans
Department of Medical Biosciences, Clinical Chemistry, Umeå University, SE 90185 Umeå, Sweden.
Kjell
K
Grankvist
Department of Immunology, Genetics, and Pathology, Biomedical Center, SciLifeLab Uppsala, Uppsala University, SE 75108 Uppsala, Sweden.
Ulf
U
Gyllensten
D000328:Adult; D000367:Age Factors; D018070:Biological Specimen Banks; D015415:Biomarkers; D001793:Blood Preservation; D001798:Blood Proteins; D015925:Cryopreservation; D005260:Female; D006801:Humans; D012621:Seasons; D013048:Specimen Handling; D013997:Time Factors
D015415:Biomarkers; D001798:Blood Proteins
Biobank; Covariate; Plasma proteins; Proximity extension assay; Sampling month; Storage time