Preanalysis storage conditions influence the measurement of brain-derived neurotrophic factor levels in peripheral blood.

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a neurotrophin that plays a pivotal role in regulating neuronal function throughout life, and this factor is regarded as a potential biomarker of mental disorders. However, previous studies have suggested that plasma BDNF levels are more variable than serum BDNF levels.

METHODS

We determined the influence of time and temperature on the measurement of peripheral blood BDNF levels. Blood samples were aliquoted into four types of tubes, including tubes containing heparin, ethylenediaminetetraacetic acid (EDTA), and citrate for plasma, and anticoagulant-free tubes for serum. The samples were stored at 4 or 25°C for 0, 1, 2, 4, 6, 24 or 48 h, and the plasma and serum BDNF levels were measured using enzyme-linked immunosorbent assay.

RESULTS

There were interindividual and interanticoagulant compound variability in the plasma BDNF levels. The measured plasma BDNF levels increased over time, whereas the serum BDNF levels remained unchanged. Furthermore, the BDNF levels detected in plasma stored in heparin tubes at 4°C and those for samples stored in EDTA tubes at 25°C were much higher than those of the other samples.

CONCLUSION

This study indicates that measurements of plasma BDNF levels are dependent not only on the anticoagulant compounds but also on the storage time and temperature conditions used after blood sampling.