A determination of the pre-analytical storage conditions for insulin like growth factor-I and type III procollagen peptide.

Author(s): Holt RI, Erotokritou-Mulligan I, Ridley SA, McHugh CM, Bassett EE, Cowan DA, Bartlett C, Sönksen PH

Publication: Growth Horm IGF Res, 2009, Vol. 19, Page 43-50

PubMed ID: 18617430 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of storage as blood, plasma or serum on levels of IGF-I and P-III-P in serum, lithium heparin-plasma and EDTA-plasma. Whole blood was centrifuged within 1 h or after experimental storage, and serum or plasma was stored frozen at -80 degrees C for up to 2 months prior to analysis. Two different immunoradiometric assays (IRMA) were used to measure IGF-I and concentrations of P-III-P, and some serum specimens were verified by radioimmunoassay (RIA).

   Summary of Findings:

   P-III-P concentrations rose by 6.5%, 6.2%, 7.0% and 6.5% with storage of clotted-blood (p=0.006), lithium-heparin blood (p=0.001), lithium-heparin plasma (p=0.002) or serum (p<0.001) at room temperature, respectively, but P-III-P concentrations were not affected by storage at 4 degrees C. The increase in serum P-III-P levels with storage at room temperature was confirmed using an RIA. P-III-P concentrations in EDTA-plasma were unaffected by storage at room temperature and were higher than those in lithium-heparin plasma or serum. IGF-I levels were comparable between serum, EDTA-plasma and lithium-heparin plasma, and up to 5 days of storage at room temperature or 4 degrees C had no effect on IGF-I concentrations. The intra-individual variability in IGF-I and P-III-P concentrations after storage was 5.5% and 25.9%, respectively, but the intra-individual variability of specimens centrifuged immediately and frozen was 3.9% and 4.1%, respectively.

   Biospecimens

   • Bodily Fluid - Blood
   • Bodily Fluid - Plasma
   • Bodily Fluid - Serum

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Protein	Immunoradiometric assay
   Peptide	Immunoradiometric assay
   Peptide	Radioimmunoassay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage temperature	Room temperature 4 degrees C
   Storage	Storage duration	<1 h 1 day 2 days 3 days 4 days 5 days
   Biospecimen Aliquots and Components	Blood and blood products	Plasma Serum Whole blood
   Immunoradiometric assay Specific	Technology platform	RIA
   Biospecimen Acquisition	Anticoagulant	EDTA Lithium heparin None
   Biospecimen Aliquots and Components	Centrifugation	Centrifugation delays investigated

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