title: In vitro Stability of Heat Shock Protein 27 in Serum and Plasma Under Different Pre-analytical Conditions: Implications for Large-Scale Clinical Studies.
abstract: The effects of storage temperatures, repeated freeze-thaw cycles, or delays in separating plasma or serum from blood samples are largely unknown for heat shock protein 27 (HSP27). We evaluated (1) the imprecision of the HSP27 assay used in this study; (2) the in vitro stability of HSP27 in blood samples stored at 4°C for up to 6 hr with immediate and delayed serum/plasma separation from cells; and (3) the in vitro stability of HSP27 in blood samples stored at -80°C after repeated freeze-thaw cycles. The ELISA to detect HSP27 in this study showed a within-run CV of <9% and a total CV of <15%. After 4-6 hr of storage at 4°C, HSP27 concentrations remained stable when using serum tubes irrespective of sample handling, but HSP27 concentrations decreased by 25-45% when using EDTA plasma tubes. Compared with baseline HSP27, one freeze-thaw cycle had no effect on serum concentrations. However, plasma concentrations increased by 3.1-fold after one freeze-thaw cycle and by 7.3-fold after five freeze-thaw cycles. In conclusion, serum is an appropriate biological sample type for use in epidemiological and large-scale clinical studies.
authors.affiliation: Christian Doppler Laboratory for Cardiac and Thoracic Diagnosis and Regeneration, Medical University of Vienna, Vienna, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Zimmermann
authors.affiliation: Christian Doppler Laboratory for Cardiac and Thoracic Diagnosis and Regeneration, Medical University of Vienna, Vienna, Austria.|Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Denise
authors.initials: D
authors.lastname: Traxler
authors.affiliation: Christian Doppler Laboratory for Cardiac and Thoracic Diagnosis and Regeneration, Medical University of Vienna, Vienna, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Simader
authors.affiliation: Christian Doppler Laboratory for Cardiac and Thoracic Diagnosis and Regeneration, Medical University of Vienna, Vienna, Austria.|Department of Gynaecology and Gynaecological Oncology, Gynecologic Cancer Unit, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
authors.forename: Christine
authors.initials: C
authors.lastname: Bekos
authors.affiliation: Department of Laboratory Medicine, Konventhospital Barmherzige Brueder Linz, Linz, Austria.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Dieplinger
authors.affiliation: Department of Cardiology, Department of Research and Education, General Hospital Celje, Celje, Slovenia.|Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Mitja
authors.initials: M
authors.lastname: Lainscak
authors.affiliation: Christian Doppler Laboratory for Cardiac and Thoracic Diagnosis and Regeneration, Medical University of Vienna, Vienna, Austria.|Department of Thoracic Surgery, Medical University of Vienna, Vienna, Austria.
authors.forename: Hendrik Jan
authors.initials: HJ
authors.lastname: Ankersmit
authors.affiliation: Department of Laboratory Medicine, Konventhospital Barmherzige Brueder Linz, Linz, Austria. thomas.mueller@bs-lab.at.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mueller
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay; D005615:Freezing; D055551:HSP27 Heat-Shock Proteins / Q000097:blood*; D006801:Humans; D055550:Protein Stability; D015203:Reproducibility of Results; D013048:Specimen Handling; D013696:Temperature; D013997:Time Factors
chemical_list: D055551:HSP27 Heat-Shock Proteins
keywords: Heat shock proteins; In vitro stability; Storage conditions