Good quality of long-term stored samples in the Janus Serum Bank
The Janus Serum Bank was established in 1973 by the Norwegian Cancer Society and is today owned by the Cancer Registry of Norway. The Janus Serum Bank consists of approximately 452 000 samples from about 317 000 Norwegian donors. The oldest samples have been stored for 30 years. The quality of these samples is still more than good enough for several purposes, as shown by Randi Gislefoss’ Thesis at the Cancer Registry of Norway.
Biobanks have become an important resource within medical research. The goal of a clinical laboratory test is to measure the concentration or activity of a component in blood or tissue, in order to give information which is relevant for the patient’s clinical status at the time of the sampling. This means that the composition of the sample must not be changed in the pre analytical phase, which includes tapping, storage, retrieval and pipetting.
Knowledge regarding handling of samples, component stability combined with a good study design and optimal assays is essential in studies on biobank material. Research fellow Randi Gislefoss has examined, through four studies, the quality of long-term stored samples in the Janus Serum Bank.
This work has discussed five main topics:
- Differences that have arisen due to non standardized pre analytical sample treatment
- Loss of water under storage
- Component stability
- Retrieval of degraded serum components by new measuring methods
- Look for possible time trends for concentration levels of singular components in the biobanks’ background population
The samples that were included in the studies were stored for up to 29 years at -25 degrees Celsius. The work showed that the analysis of the calcium component may give information regarding extended coagulation time in the pre analytical phase.
Analysis of Sodium indicated a loss of water of 4%. Many serum components (calcium, iron, creatinin, uric acid, albumin, cystatin C, immunoglobulins and some transport proteins) are relatively stable after 25 years of storage, while components such as ferritin, bilirubin, two enzymes (ALAT and CK), including the Folic Acid vitamin are degraded.
For some of the components (CK and Folic Acid) the choice of method can be of importance in measuring the original level of the long-term samples.
A substantially lower testosterone level was found in samples from 2008 compared to samples from 1979. This may indicate changes in the background population.