Measurement of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 after delayed separation of whole blood samples.
OBJECTIVE
Epidemiological studies benefit from unbiased blood specimens collected with minimal cost and effort of blood collection and storage. We evaluated the stability of IGF-1 and IGFBP-3 in whole blood samples stored at room temperature to justify delays in blood processing.


METHODS
Total IGF-1 and IGFBP-3 levels were measured in EDTA plasma (n=12), heparin plasma (n=12) and serum (n=10) samples of healthy volunteers after blood processing delays up till 14 days. Stability of measured IGF-1 and IGFBP-3 levels was tested by paired t-test and a linear mixed effect model.


RESULTS
Longitudinal analysis showed that IGF-1 levels were not significantly affected by blood processing delays in EDTA tubes (p=0.18) and IGFBP-3 levels were marginally stable (p=0.06). In heparin plasma and serum, however, IGF-1 increased over time of delayed processing and IGFBP-3 levels tended to decrease (p<0.01).


CONCLUSIONS
Total IGF-1 and IGFBP-3 levels are stable in whole blood collected in EDTA tubes at room temperature up till 7 days, allowing a delay in blood processing to reduce costs in large multi-center studies.
Hartog
Hermien
H
Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
van der Graaf
Winette T A
WT
Wesseling
Jelle
J
van der Veer
Eveline
E
Boezen
H Marike
HM
D000328:Adult; D001781:Blood Component Removal / Q000592:standards; D001800:Blood Specimen Collection / Q000592:standards*; D004355:Drug Stability; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000032:analysis / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism*; D008137:Longitudinal Studies; D008875:Middle Aged; D013997:Time Factors
D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I