Serum levels of insulin-like growth factor-I and insulin-like growth factor-I binding protein-3: quality control for studies of stored serum.
Author(s): Berrigan D, Potischman N, Dodd KW, Nicar M, McQuillan G, Lavigne JA, Barrett JC, Ballard-Barbash R
Publication: Cancer Epidemiol Biomarkers Prev, 2007, Vol. 16, Page 1017-22
PubMed ID: 17507631 PubMed Review Paper? No
Suggested by: ISBER
Purpose of Paper
The purpose of this paper was to determine the effects of storage history, freeze-thaw cycling, patient gender, and assay conditions on insulin-like growth factor (IGF) and IGF binding protein-3 (IGFBP-3) levels in serum.
Conclusion of Paper
The authors report that IGF and IGFBP-3 degradation was not dependent on patient age or ethnicity, but that IGFBP-3 degradation rates were somewhat higher in women than men (p=0.035). In the specimens sent to Atlanta, a second freeze-thaw cycle had no effect on the stability of either protein. IGF and IGFBP-3 levels tended to be higher in the outer plate wells than in the central wells (p=0.0482).
Studies
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Study Purpose
The purpose of this study was to determine the effects of storage history, freeze-thaw cycling, patient gender, and assay conditions on IGF and IGFBP-3 in serum. Some specimens were frozen immediately, shipped to the laboratories, stored at -80 degrees C, and thawed more than once with variable time at room temperature and 4 degrees C, while other specimens were frozen, shipped to Atlanta, thawed on ice, aliquoted, and stored in liquid nitrogen.
Summary of Findings:
Levels of IGF and IGFBP-3 were 43% and 25% lower, respectively, in specimens sent to laboratories for 10-16 years of storage at -80 degrees C (including some additional freeze-thaw cycling) compared to specimens shipped to Atlanta and stored in liquid nitrogen with no additional freeze-thaw cycling. The authors report that degradation of either protein was not dependent on patient age or ethnicity, but that IGFBP-3 degradation was somewhat higher in women than men (p=0.035). In the specimens sent to Atlanta, the second freeze-thaw cycle had no effects on the stability of either protein. Levels of IGF and IGFBP-3 tended to be higher in the outer plate wells than in the central wells (p=0.0482).
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Protein ELISA Protein Immunoradiometric assay Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage temperature Liquid nitrogen
-80 degrees C
4 degrees C
Room temperature
Storage Storage duration 10-16 years
Storage Freeze/thaw cycling 1 cycle
2 cycles
Preaquisition Patient gender Female
Male
ELISA Specific Targeted peptide/protein IGF-I
IGFBP-3
ELISA Specific Specimen position Center of plate
Periphery of plate