Abstract
Biorepositories have become an important resource in cancer epidemiology. One of the aspects of biobank activities is to evaluate the quality of the samples.
The present work has addressed five main issues relevant to examination of archival serum samples:
- Differences induced by non-standardised preanalytical sample handling
- Sublimation during storage
- Component stability
- Recovery of a degraded serum component
- Possible time trends in population levels of serum components
Increased potassium and decreased bilirubin, pointed to prolonged clot- time and light exposure. The sodium levels indicated sublimation of 4%. There were small changes in calcium, iron, creatinine, uric acid, albumin, AST, cystatin C, IgE, IgG, SHBG, and transferrin after 25 years of storage at –25 ºC. Ferritin, ALAT, CK and folate proved vulnerable to degradation. Substantial lower level of testosterone in fresh samples compared to 29 year-old ones, suggested changes in the background population. Knowledge of component stability, and optimal assays are essential in studies on archival serum samples.