Long-term stability of soluble ST2 in frozen plasma samples.
OBJECTIVE
The aim of this study was to investigate the long-term in vitro stability of soluble ST2 (sST2).


METHODS
EDTA plasma samples were drawn from 15 individuals with various diseases. The Presage ST2 assay was used for measurement of sST2 concentrations directly after blood collection and after storing plasma samples for 18 months at -20 degrees C and -80 degrees C. The default criterion for analyte stability was set at 95%.


RESULTS
sST2 concentrations in the 15 individuals ranged from 12 U/mL to 140 U/mL. Directly after blood collection, the mean (+/-SD) sST2 concentration was 51+/-37 U/mL, and absolute analyte recoveries were 50+/-35 U/mL and 51+/-34 U/mL after storage of samples for 18 months at -20 degrees C and -80 degrees C, respectively. Relative analyte recoveries after 18 months of storage at -20 degrees C and -80 degrees C were 99+/-5% and 101+/-7%.


CONCLUSIONS
sST2 is stable for at least 1.5 years in plasma samples stored at -20 degrees C and -80 degrees C.
Dieplinger
Benjamin
B
Department of Laboratory Medicine, Konventhospital Barmherzige Brueder, Seilerstaette 2-4, A-4020 Linz, Austria. benjamin.dieplinger@bs-lab.at
Egger
Margot
M
Poelz
Werner
W
Haltmayer
Meinhard
M
Mueller
Thomas
T
D001793:Blood Preservation / Q000379:methods; D015925:Cryopreservation / Q000379:methods; D004492:Edetic Acid; D006801:Humans; D000072179:Interleukin-1 Receptor-Like 1 Protein; D010949:Plasma / Q000737:chemistry*; D055550:Protein Stability; D011956:Receptors, Cell Surface / Q000737:chemistry*; D013696:Temperature
C079241:IL1RL1 protein, human; D000072179:Interleukin-1 Receptor-Like 1 Protein; D011956:Receptors, Cell Surface; D004492:Edetic Acid