Reproducibility and accuracy of measurements of free and total prostate-specific antigen in serum vs plasma after long-term storage at -20 degrees C.
Author(s): Ulmert D, Becker C, Nilsson JA, Piironen T, Björk T, Hugosson J, Berglund G, Lilja H
Publication: Clin Chem, 2006, Vol. 52, Page 235-9
PubMed ID: 16384894 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to determine the effects of long-term frozen storage of plasma and serum on concentrations of total prostate specific antigen (tPSA), free PSA (fPSA) and complexed PSA (cPSA).
Conclusion of Paper
tPSA, fPSA and cPSA levels in EDTA-plasma were unaffected by 20 years of frozen storage. After long-term storage, slightly more tPSA was present in EDTA-plasma than serum, and the authors report more variability in fPSA after storage of serum compared to in EDTA-plasma stored < 2 weeks.
Studies
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Study Purpose
The purpose of this study was to determine the effects of long-term frozen storage of plasma and serum on concentrations of tPSA, fPSA and cPSA. EDTA-plasma and serum from age matched patients were compared with archival plasma and serum frozen for 20 years at -20 degrees C.
Summary of Findings:
EDTA-plasma and serum stored for <2 weeks had comparable levels of tPSA, fPSA and cPSA. Similar levels of fPSA and cPSA were observed in EDTA-plasma and serum after 20 years of frozen storage; however, slightly more tPSA was present in EDTA-plasma than serum (p=0.009) after 20 years of storage. Serum stored for 20 years had comparable levels of tPSA, fPSA and cPSA to those measured in EDTA-plasma stored for <2 weeks, but the authors report more variability in serum fPSA after 20 years of storage than in EDTA-plasma stored <2 weeks.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Protein Fluorometry Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage duration <2 weeks
20 years
Biospecimen Aliquots and Components Blood and blood products Plasma
Serum